Diving disorders, or diving related medical conditions, are conditions associated with
underwater diving
Underwater diving, as a human activity, is the practice of descending below the water's surface to interact with the environment. It is also often referred to as diving (disambiguation), diving, an ambiguous term with several possible meani ...
, and include both conditions unique to underwater diving, and those that also occur during other activities. This second group further divides conditions caused by exposure to
ambient pressure
The ambient pressure on an object is the pressure of the surrounding medium, such as a gas or liquid, in contact with the object.
Atmosphere
Within the atmosphere, the ambient pressure decreases as elevation increases. By measuring ambient atmosp ...
s significantly different from surface
atmospheric pressure
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013. ...
, and a range of conditions caused by general environment and equipment associated with diving activities.
Disorders particularly associated with diving include those caused by variations in ambient pressure, such as barotraumas of descent and ascent, decompression sickness and those caused by exposure to elevated ambient pressure, such as some types of gas toxicity. There are also non-dysbaric disorders associated with diving, which include the effects of the aquatic environment, such as drowning, which also are common to other water users, and disorders caused by the equipment or associated factors, such as carbon dioxide and carbon monoxide poisoning. General environmental conditions can lead to another group of disorders, which include hypothermia and motion sickness, injuries by marine and aquatic organisms,
contaminated waters, man-made hazards, and ergonomic problems with equipment. Finally there are pre-existing medical and
psychological conditions which increase the risk of being affected by a diving disorder, which may be aggravated by adverse side effects of
medication
Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to medical diagnosis, diagnose, cure, treat, or preventive medicine, prevent disease. Drug therapy (pharmaco ...
s and other drug use.
Treatment depends on the specific disorder, but often includes
oxygen therapy
Oxygen therapy, also referred to as supplemental oxygen, is the use of oxygen as medical treatment. Supplemental oxygen can also refer to the use of oxygen enriched air at altitude. Acute indications for therapy include hypoxemia (low blood o ...
, which is standard first aid for most diving accidents, and is hardly ever contra-indicated for a person medically fit to dive, and
hyperbaric
Hyperbaric medicine is medical treatment in which an increase in barometric pressure of typically air or oxygen is used. The immediate effects include reducing the size of gas emboli and raising the partial pressures of the gases present. Initial ...
therapy is the definitive treatment for decompression sickness. Screening for
medical fitness to dive can reduce some of the risk for some of the disorders.
Effects of variation in ambient pressure

Many diving accidents or illnesses are related to the effect of
pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...
on gases in the body.
Barotrauma
Barotrauma is physical injury to body tissues caused by a difference in
pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...
between a gas space inside or in contact with the body, and the surroundings.
Barotrauma occurs when the difference in pressure between the surroundings and the gas space makes the gas change in volume, distorting adjacent tissues enough to rupture
cells or damage
tissue by deformation. A special case, where pressure in tissue is reduced to the level that causes dissolved gas to come out of solution as bubbles, is called ''
decompression sickness
Decompression sickness (DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from Solution (chemistry), solution as bubbles inside the body tissues during D ...
'', ''the bends'', or ''caisson disease''.
Several organs are susceptible to barotrauma; however, the cause is well understood and procedures for avoidance are clear. Nevertheless, barotrauma occurs and can be life-threatening, and procedures for first aid and further treatment are an important part of diving medicine.

*Barotraumas of descent (squeezes)
**Ear squeeze (also
alternobaric vertigo
In aviation and underwater diving, alternobaric vertigo is dizziness resulting from unequal pressures being exerted between the inner ears, commonly due to one Eustachian tube being less patent than the other.
Signs and symptoms
Causes
This m ...
)
**Sinus squeeze (
aerosinusitis
Aerosinusitis, also called barosinusitis, sinus squeeze or sinus barotrauma is a painful inflammation and sometimes bleeding of the membrane of the paranasal sinus cavities, normally the frontal sinus. It is caused by a difference in air pressure ...
)
**Tooth squeeze (
dental barotrauma,
barodontalgia
Barodontalgia, commonly known as tooth squeeze, is a pain in a tooth caused by a change in ambient pressure. The pain usually ceases at return to the original pressure. Dental barotrauma is a condition in which such changes in ambient pressure cau ...
)
**Mask squeeze
**Helmet squeeze
**Suit squeeze
*Barotraumas of ascent (overexpansion injuries)
**Lung overexpansion injury (pulmonary barotrauma) – rupture of lung tissue allowing air to enter tissues, blood vessels, or spaces between or surrounding organs:
***Pneumothorax: Free air in the pleural cavity, leading to collapsed lung.
***Interstitial emphysema: Gas trapped in the spaces between tissues.
***Mediastinal emphysema: Gas trapped around the heart.
***Subcutaneous emphysema: Free gas under the skin.
**
Arterial gas embolism
An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. Air can be introduced into the circulation during surgical procedures, lung over-expansi ...
: Air or other breathing gas in the blood stream, causing blockage of small blood vessels.
**Intestinal gas overexpansion
**Middle ear overpressure (reversed ear) (also
alternobaric vertigo
In aviation and underwater diving, alternobaric vertigo is dizziness resulting from unequal pressures being exerted between the inner ears, commonly due to one Eustachian tube being less patent than the other.
Signs and symptoms
Causes
This m ...
)
**Sinus overpressure (
aerosinusitis
Aerosinusitis, also called barosinusitis, sinus squeeze or sinus barotrauma is a painful inflammation and sometimes bleeding of the membrane of the paranasal sinus cavities, normally the frontal sinus. It is caused by a difference in air pressure ...
)
**Tooth overpressure (
dental barotrauma,
barodontalgia
Barodontalgia, commonly known as tooth squeeze, is a pain in a tooth caused by a change in ambient pressure. The pain usually ceases at return to the original pressure. Dental barotrauma is a condition in which such changes in ambient pressure cau ...
)
Compression arthralgia
Compression arthralgia is pain in the joints caused by exposure to high ambient pressure at a relatively high rate of compression, experienced by underwater divers. Also referred to in the US Navy Diving Manual as compression pains. Fast compression (descent) may produce symptoms as shallow as 30 msw. At depths beyond 180m even very slow compression may produce symptoms. The pain may be sufficiently severe to limit the diver's capacity for work, and may also limit travel rate and depth of downward excursions by saturation divers. The symptoms generally resolve during decompression and require no further treatment.
Decompression sickness
Decompression sickness is a condition caused by dissolved gases coming out of solution as bubbles in the tissues and fluids of the body during and directly after depressurisation. DCS is best known as a
hazard of underwater diving but may occur in other decompression events such as
caisson work, flying in unpressurised aircraft, and
extra-vehicular activity
Extravehicular activity (EVA) is any activity done by an astronaut in outer space outside a spacecraft. In the absence of a breathable Earthlike atmosphere, the astronaut is completely reliant on a space suit for environmental support. EVA i ...
from spacecraft. Since bubbles can form in any part of the body, or migrate via the bloodstream to any part of the body, DCS can produce a wide range of symptoms, and its effects may vary from joint pain and skin rashes to paralysis and death.
Symptoms:
* Loss of bowel or bladder function
* Collapse or
unconsciousness
Unconsciousness is a state in which a living individual exhibits a complete, or near-complete, inability to maintain an awareness of self and environment or to respond to any human or environmental stimulus. Unconsciousness may occur as the r ...
* Coughing spasms or shortness of breath
* Dizziness
* Unusual fatigue
* Itching
* Joint aches or pain
* Mottling or marbling of skin
* Numbness or tingling
*
Paralysis
Paralysis (: paralyses; also known as plegia) is a loss of Motor skill, motor function in one or more Skeletal muscle, muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory d ...
* Personality changes
* Staggering, loss of coordination, or tremors
* Weakness
Dysbaric osteonecrosis
Dysbaric osteonecrosis, also known as aseptic bone necrosis, is generally a longer term effect on the bones and joints of divers caused by decompression bubbles and may occur even if no clinical decompression sickness has been diagnosed.
High pressure nervous syndrome
High-pressure nervous syndrome (HPNS) is a
neurological
Neurology (from , "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the nervous system, which comprises the brain, the s ...
and
physiological
Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...
diving disorder that results when a
diver descends below about while breathing a helium–oxygen mixture. The effects depend on the rate of descent and the depth. The effects of HPNS comprise trembling, myoclonic jerks, drowsiness, alterations in EEG patterns, visual disruptions, queasiness, vertigo, and diminished cognitive function.
Nitrogen narcosis
Nitrogen narcosis is a reversible alteration in consciousness that occurs while breathing gas with a high partial pressure of nitrogen. The effect is similar to alcohol intoxication or nitrous oxide inhalation and does not usually become noticeable at nitrogen partial pressures less than about 3 bar, equivalent to a depth of about 30 meters (100 ft) on air. As depth increases, the mental impairment may become hazardous. Divers can learn to cope with some of the effects of narcosis, but it is impossible to develop a tolerance. Narcosis affects all divers breathing gas mixtures containing nitrogen, although susceptibility varies widely from dive to dive, and between individuals. One of the risks of Nitrogen narcosis is that divers may remove their regulator or fail to follow proper safety procedures.
Oxygen toxicity
Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen ()
partial pressure
In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal g ...
s significantly greater than found in atmospheric air at sea level. Severe cases can result in
cell damage
Cell damage (also known as cell injury) is a variety of changes of stress that a cell suffers due to external as well as internal environmental changes. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutrition ...
and death, with effects most often seen in the central nervous system, lungs and eyes.
Divers are exposed to raised partial pressures of oxygen in normal diving activities, where the partial pressure of oxygen in the breathing gas is increased in proportion to the
ambient pressure
The ambient pressure on an object is the pressure of the surrounding medium, such as a gas or liquid, in contact with the object.
Atmosphere
Within the atmosphere, the ambient pressure decreases as elevation increases. By measuring ambient atmosp ...
at depth, and by using
gas mixtures in which oxygen is substituted for inert gases to reduce decompression obligations, to
accelerate decompression, or reduce the risk of
decompression sickness
Decompression sickness (DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from Solution (chemistry), solution as bubbles inside the body tissues during D ...
.
They are also exposed to raised partial pressures of oxygen if given oxygen as first aid, which is a standard protocol for most acute diving related disorders, and when undergoing hyperbaric oxygen therapy in the case of decompression sickness or
arterial gas embolism
An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system. Air can be introduced into the circulation during surgical procedures, lung over-expansi ...
.
Non-dysbaric disorders associated with diving
Drowning
"Drowning is the process of experiencing respiratory impairment from submersion/immersion in liquid".
Near drowning is the survival of a drowning event involving unconsciousness or water inhalation and can lead to serious secondary complications, including death, after the event.
Drowning is usually the culmination of a deteriorating sequence of events in a diving accident, and is seldom a satisfactory explanation for a fatality, as it fails to explain the underlying causes and complications that led to the final consequence.
Generally, a diver is well prepared for the environment, and well trained and equipped to deal with it. A diver should not drown merely as a result of being in the water.
Salt water aspiration syndrome
Salt water aspiration syndrome is a rare diving disorder experienced by
divers who inhale a mist of
seawater
Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximat ...
from a faulty
demand valve causing irritation of the
lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s.
It canusually be treated by rest for several hours. If severe, medical assessment is required.
Hypoxia
Hypoxia is a
pathological
Pathology is the study of disease. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatme ...
condition in which the body as a whole or a region of the body is deprived of adequate
oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise. A mismatch between oxygen supply and its demand at the cellular level may result in a hypoxic condition.
Generalized hypoxia occurs when breathing mixtures of gases with a low oxygen content, e.g. while diving underwater especially when using closed-circuit
rebreather
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantial unused oxygen content, and unused inert content when present, of each breath. Oxygen is a ...
systems that control the amount of oxygen in the supplied air, or when breathing gas mixtures blended to prevent oxygen toxicity at depths below about 60 m near or at the surface. This condition may lead to a loss of consciousness underwater and consequent death either directly by cerebral hypoxia, or indirectly by drowning.
Latent hypoxia may occur when a breathhold diver surfaces. This is also known as
deep water blackout. The consequence is likely to be drowning.
Tissue hypoxia occurs when arterial gas emboli due to either lung overexpansion injury or
decompression sickness
Decompression sickness (DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from Solution (chemistry), solution as bubbles inside the body tissues during D ...
block systemic capillaries and shut off the supply of oxygenated blood to the tissues downstream. If untreated, this leads to tissue damage or death, with consequences that depend on the site and extent of the injury.
Swimming-induced pulmonary edema
Swimming-induced pulmonary edema (SIPE) occurs when fluids from the blood leak abnormally from the small vessels of the lung (pulmonary capillaries) into the airspaces (alveoli).
SIPE usually occurs during heavy exertion in conditions of water immersion, such as swimming and diving. It has been reported in
scuba diver
Scuba, originally SCUBA, often expanded to scuba set, is any self contained underwater breathing apparatus, a source of breathing gas used for underwater diving which is carried by the diver.
Scuba may also refer to:
* Scuba diving
Scuba ...
s,
apnea (breath hold)
free-diving
Freediving, free-diving, free diving, breath-hold diving, or skin diving, is a mode of underwater diving that relies on apnea, breath-holding until resurfacing rather than the use of breathing apparatus such as scuba set, scuba gear.
Besides the ...
competitors,
combat swimmers,
and
triathletes.
[ The causes are incompletely understood at the present time.]
Immersion diuresis
Immersion diuresis is a type of diuresis
Diuresis () is the excretion of urine, especially when excessive (polyuria). The term collectively denotes the physiologic processes underpinning increased urine production by the kidneys during maintenance of fluid balance.
In healthy people, ...
caused by immersion of the body in water (or equivalent liquid). It is mainly caused by lower temperature and by pressure.
The ''temperature'' effect is caused by vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vesse ...
of the cutaneous blood vessel
Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...
s within the body to conserve heat. The body detects an increase in the blood pressure
Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...
and inhibits the release of vasopressin
Mammalian vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the ''AVP'' gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It ...
, causing an increase in the production of urine
Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...
.
The ''pressure'' effect is caused by the hydrostatic pressure
Hydrostatics is the branch of fluid mechanics that studies fluids at hydrostatic equilibrium and "the pressure in a fluid or exerted by a fluid on an immersed body". The word "hydrostatics" is sometimes used to refer specifically to water and o ...
of the water directly increasing blood pressure. Its significance is indicated by the fact that the temperature of the water doesn't substantially affect the rate of diuresis. Partial immersion of only the limbs does not cause increased urination.
Diuresis is significant in diving medicine as the consequent mild dehydration may be a contributing factor in the onset of decompression sickness.
Hypercapnia
Hypercapnia is a condition where there is too much carbon dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
(CO2) in the blood.
Divers may develop this condition for several possible reasons:
* Increased work of breathing
Work of breathing (WOB) is the energy expended to inhale and exhale a breathing gas. It is usually expressed as work per unit volume, for example, joules/litre, or as a work rate (power), such as joules/min or equivalent units, as it is not parti ...
due to increased density of the breathing das with depth.
* Inadequate ventilatory response to exertion.[
*]Dead space
''Dead Space'' is a science fiction horror franchise created and directed by Glen Schofield. ''Dead Space'' was developed by Visceral Games and published and owned by Electronic Arts. The franchise's chronology is not presented in a linear format ...
of the breathing apparatus.[
* Higher inspired CO2 due to failure of the ]carbon dioxide scrubber
A carbon dioxide scrubber is a piece of equipment that absorbs carbon dioxide (CO2). It is used to treat exhaust gases from industrial plants or from exhaled air in life support systems such as rebreathers or in spacecraft, submersible craft or ...
in the diver's rebreather
A rebreather is a breathing apparatus that absorbs the carbon dioxide of a user's exhaled breath to permit the rebreathing (recycling) of the substantial unused oxygen content, and unused inert content when present, of each breath. Oxygen is a ...
to remove sufficient carbon dioxide from the loop.
* Over-exertion, producing excess carbon dioxide due to elevated metabolic activity.
* Deliberate hypoventilation
Hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (''hypo'' meaning "below") to perform needed respiratory gas exchange. By definition it causes an increased concentration of carbon dioxide ( hypercap ...
, known as "skip breathing".
* Shallow breathing, due to stress or other reasons.
* Contamination of the breathing gas supply.
As severe hypercapnia may produce disorientation, panic
Panic is a sudden sensation of fear, which is so strong as to dominate or prevent reason and logical thinking, replacing it with overwhelming feelings of anxiety, uncertainty and frantic agitation consistent with a fight-or-flight reaction. ...
, hyperventilation
Hyperventilation is irregular breathing that occurs when the rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce. This leads to hypocapnia, a reduced concentration of carbon dioxide dissolved in the blo ...
, convulsions
A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is often used as a synony ...
, unconsciousness
Unconsciousness is a state in which a living individual exhibits a complete, or near-complete, inability to maintain an awareness of self and environment or to respond to any human or environmental stimulus. Unconsciousness may occur as the r ...
, and eventually death
Death is the end of life; the irreversible cessation of all biological functions that sustain a living organism. Death eventually and inevitably occurs in all organisms. The remains of a former organism normally begin to decompose sh ...
. it is important for divers, supervisors and life support technicians to recognise the symptoms and development of the condition in time to correct the situation.
Carbon monoxide poisoning
Carbon monoxide poisoning occurs by inhalation of carbon monoxide
Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...
(CO). Carbon monoxide is a toxic gas, but, being colorless, odorless, tasteless, and initially non-irritating, it is very difficult for people to detect. Carbon monoxide is a product of incomplete combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...
of organic matter due to insufficient oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
supply to enable complete oxidation to carbon dioxide (CO2). Breathing gas for diving may be contaminated either by intake of contaminated atmospheric air, usually from internal combustion exhaust gases, or, more rarely, by carbon monoxide produced in the compressor by partial combustion of lubricants.
The effects of carbon monoxide in breathing gas
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas, but other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed ...
are increased in proportion to the depth, as the partial pressure of the contaminant is increased in proportion to the depth for a given gas fraction. The permitted levels of carbon monoxide in breathing gas for diving is lower than for at atmospheric pressure due to the concentrating effect of raised ambient pressure.
Lipid pneumonia
Lipid pneumonia is a specific form of lung inflammation (pneumonia
Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...
) that develops when lipids
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins Vitamin A, A, Vitamin D, D, Vitamin E, E and Vitamin K, K), monoglycerides, diglycerides, phospholipids, and others. The fu ...
enter the bronchial tree. In diving this can happen when the breathing gas supply is contaminated with lubricants from the compressor, but it is very rare.
Environmental hazards
Hazards in the underwater environment that can affect divers include marine life, marine infections, polluted water, ocean current
An ocean current is a continuous, directed movement of seawater generated by a number of forces acting upon the water, including wind, the Coriolis effect, breaking waves, cabbeling, and temperature and salinity differences. Depth contours, sh ...
s, waves and surges and man-made hazards such as boats, fishing lines and underwater construction. Diving medical personnel need to be able to recognize and treat accidents from large and small predators and poisonous creatures, appropriately diagnose and treat marine infections and illnesses from pollution as well as diverse maladies such as sea sickness, traveler's diarrhea and malaria
Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...
.
Hypothermia
Hypothermia is a condition in which core temperature drops below the required temperature for normal metabolism
Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...
and body functions (Clinical hypothermia is defined as below ). Body temperature
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
is usually maintained near a constant level of through biological homeostasis
In biology, homeostasis (British English, British also homoeostasis; ) is the state of steady internal physics, physical and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning fo ...
or thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
. If exposed to cold and the internal mechanisms are unable to replenish the heat that is being lost, a drop in core temperature occurs. As body temperature decreases, characteristic symptoms occur such as shivering
Shivering (also called shuddering) is a bodily function in response to cold and extreme fear in warm-blooded animals. When the core body temperature drops, the shivering reflex is triggered to maintain homeostasis. Skeletal muscles begin to sha ...
and mental confusion
In psychology, confusion is the quality or emotional state of being bewildered or unclear. The term "acute mental confusion" .
Hypothermia usually occurs from exposure to low temperatures, but any condition that decreases heat production, increases heat loss, or impairs thermoregulation may contribute. Heat is lost more quickly in water than on land, and also more quickly in proportion to wind speed. Water temperatures that would be quite reasonable as outdoor air temperatures can lead to hypothermia. Divers are often exposed to low water temperatures and wind chill, which may be aggravated by evaporative cooling of wet dive suits, and mild hypothermia is not uncommon in both recreational and professional divers, while moderate to severe hypothermia remains a significant risk.
Clinical hypothermia (defined by a drop in core temperature below 35 °C) is unusual during the dive in scuba divers wearing reasonable thermal protection, as even a leaking dry suit reduces heat loss considerably.
In deep diving, where the gas density is relatively high, the heat loss to breathing gas can be a large part of the total heat loss, and can by itself exceed the metabolic heat production, making it necessary to heat the gas supply before inhalation. The peripheral vasoconstriction that occurs when the skin is chilled does not protect against heat loss from the lungs. Helium has a lower heat capacity than nitrogen, but a higher thermal conductivity. It has several advantages as a breathing gas at high pressures, but disadvantages as an ambient atmosphere in diving bells and dry suits, where heat loss through the surrounding gas is increased.
Non-freezing cold injuries
Exposure of the extremities in water temperatures below 12 °C (53.6 °F) can cause permanent damage. NFCI is a class of tissue damage caused by sustained exposure to low temperature without actual freezing
Freezing is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point.
For most substances, the melting and freezing points are the same temperature; however, certain substances possess dif ...
. Experimental evidence suggests a complex mode of injury with microvascular disruption, cyclic ischaemia, reperfusion injury
Reperfusion injury, sometimes called ischemia-reperfusion injury (IRI) or reoxygenation injury, is the tissue damage caused when blood supply returns to tissue ('' re-'' + ''perfusion'') after a period of ischemia or lack of oxygen (anoxia or hy ...
and direct damage to nerves due to cold.
Frostbite
Tissue damage by freezing of the extremities is a hazard of ice diving, mainly when the diver is on the ice after the dive, and particularly if there is wind chill.
Hyperthermia
Overheating may occur on the surface when the diver is preparing to dive, or on standby in heavily insulated exposure suit, or in the water, if the suit is excessively insulated for the conditions, the water temperature is too high, or the supply to a hot water suit is too hot.
Seasickness
Seasickness is a form of motion sickness
Motion sickness occurs due to a difference between actual and expected motion. Symptoms commonly include nausea, vomiting, cold sweat, headache, dizziness, tiredness, loss of appetite, and increased salivation. Complications may rarely include ...
, a condition in which a disagreement exists between visually perceived movement and the vestibular system
The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating motor coordination, movement with balance. Together with the cochlea, a part of the auditory sys ...
's sense of movement characterized by a feeling of nausea
Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat.
Over 30 d ...
and, in extreme cases, vertigo
Vertigo is a condition in which a person has the sensation that they are moving, or that objects around them are moving, when they are not. Often it feels like a spinning or swaying movement. It may be associated with nausea, vomiting, perspira ...
, experienced after spending time on a craft on water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
, floating at the surface of a rough sea, and in strong surge near the bottom.
Seasickness can significantly reduce the ability of a diver to effectively complete a task or manage a contingency, and may predispose the diver to hypothermia and decompression sickness.
Cramps
A cramp is a sudden, involuntary, painful muscle contraction
Muscle contraction is the activation of Tension (physics), tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in musc ...
or overshortening; while generally temporary and non-damaging, they can cause significant pain
Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...
and a paralysis
Paralysis (: paralyses; also known as plegia) is a loss of Motor skill, motor function in one or more Skeletal muscle, muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory d ...
-like immobility of the affected muscle. Muscle cramps are common and are often associated with pregnancy, physical exercise or overexertion, age (common in older adults), or may be a sign of a motor neuron
A motor neuron (or motoneuron), also known as efferent neuron is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly o ...
disorder.
Cramps may occur in a skeletal muscle
Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...
or smooth muscle
Smooth muscle is one of the three major types of vertebrate muscle tissue, the others being skeletal and cardiac muscle. It can also be found in invertebrates and is controlled by the autonomic nervous system. It is non- striated, so-called bec ...
. Skeletal muscle cramps may be caused by muscle fatigue
Muscle fatigue is when muscles that were initially generating a normal amount of force, then experience a declining ability to generate force. It can be a result of vigorous exercise, but abnormal fatigue may be caused by barriers to or interfer ...
or a lack of electrolyte
An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble Salt (chemistry), salts, acids, and Base (chemistry), bases, dissolved in a polar solven ...
s such as sodium
Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
(a condition called hyponatremia
Hyponatremia or hyponatraemia is a low concentration of sodium in the Serum (blood), blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. Symp ...
), potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
(called hypokalemia
Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an a ...
), or magnesium
Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
(called hypomagnesemia
Magnesium deficiency is an electrolyte disturbance in which there is a low level of magnesium in the body. Symptoms include tremor, poor coordination, muscle spasms, loss of appetite, personality changes, and nystagmus. Complications may in ...
). Some skeletal muscle cramps do not have a known cause. Cramps of smooth muscle may be due to menstruation
Menstruation (also known as a period, among other colloquial terms) is the regular discharge of blood and Mucous membrane, mucosal tissue from the endometrium, inner lining of the uterus through the vagina. The menstrual cycle is characterized ...
or gastroenteritis
Gastroenteritis, also known as infectious diarrhea, is an inflammation of the Human gastrointestinal tract, gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of ...
. Motor neuron disorders (e.g., amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or—in the United States—Lou Gehrig's disease (LGD), is a rare, Terminal illness, terminal neurodegenerative disease, neurodegenerative disorder that results i ...
), metabolic disorders
A metabolic disorder is a disorder that negatively alters the body's processing and distribution of macronutrients, such as proteins, fats, and carbohydrates. Metabolic disorders can happen when abnormal chemical reactions in the body alter the ...
(e.g., liver failure
Liver failure is the inability of the liver to perform its normal synthetic and metabolic functions as part of normal physiology. Two forms are recognised, acute and chronic (cirrhosis). Recently, a third form of liver failure known as acute- ...
), some medications (e.g., diuretic
A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics ...
s and inhaled beta‐agonists), and haemodialysis
Hemodialysis, also spelled haemodialysis, or simply ''"'dialysis'"'', is a process of filtering the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as c ...
may also cause muscle cramps.
A cramp usually starts suddenly and it also usually goes away on its own over a period of several seconds, minutes, or hours.
Injury caused by marine animals
Envenomation
Bites
Blunt trauma
Marine microbial infection
Microbes can infect through injured skin, the mucosa
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It ...
, or inhalation. Nonfatal drowning
Drowning is a type of Asphyxia, suffocation induced by the submersion of the mouth and nose in a liquid. Submersion injury refers to both drowning and near-miss incidents. Most instances of fatal drowning occur alone or in situations where othe ...
in marine environments brings seawater into the lungs where the water goes through our nose or through the mouth resulting in pneumonia
Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...
. Aerosolized water can contain algal toxin
A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived ...
s and can result in virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...
es to become airborne. Infectious diseases are predominantly caused by pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...
s which are virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...
es, bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...
, fungi
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
and protist
A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancest ...
parasites.
Contamination from polluted waters
In most places, contamination comes from a variety of sources (non-point source pollution). In a few it is primarily pollution from a single industrial source. The more immediate threat is from locations where high concentrations of toxic or pathogenic pollutants are present, but lower concentrations of less immediately harmful contaminants can have a longer term influence on the diver's health. Three major categories of contamination can cause health and safety problems for divers. These are biological, chemical and radioactive materials.
The risks from hazardous materials are generally proportional to dosage - exposure time and concentration, and the effects of the material on the body. This is particularly the case with chemical and radiological contaminants. There may be a threshold limit value which will not usually produce ill effects over long-term exposure. Others may have a cumulative effect.
The United Nations identification numbers for hazardous materials classifies hazardous materials under 9 categories:
# Explosives
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...
# Gases
Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such ...
, which may be compressed, liquified or dissolved under pressure
# Flammable liquids
# Flammable solids
# Oxidising agents
# Poisonous and infectious substances
# Radioactive substances
# Corrosive substances
# Miscellaneous hazardous substances
A contaminant may be classed under one or more of these categories.
Poison
A poison is any chemical substance that is harmful or lethal to living organisms. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figurati ...
ous substances are also classified in 9 categories:
# Irritants
# Simple asphyxiants
# Blood asphyxiants
# Tissue asphyxiants
# Respiratory paralysers
# Liver and kidney toxins
# Substances that affect the muscles ( myotoxins)
# Substances that affect bone marrow
# Substances that interfere with nerve function (neurotoxins
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature n ...
)
Trauma due to the natural physical environment
Water movement due to waves or currents may wash the diver against hard or sharp edged obstacles, or the movement of the diver may cause impact, or unstable bottom formations may fall onto the diver, causing injury.
Injuries caused by man-made hazards
In addition to mechanisms similar to those for natural hazards, injuries caused by impact with the dive boat or other vessels or their moving parts, like propellers and thrusters, and by tools and equipment is possible. The nature of work related injury depends on the task and equipment in use.
Disorders caused by the diving equipment
A variety of disorders may be caused by ergonomic problems due to poorly fitting equipment.
*Temporomandibular joint dysfunction
Temporomandibular joint dysfunction (TMD, TMJD) is an umbrella term covering pain and dysfunction of the muscles of mastication (the muscles that move the jaw) and the temporomandibular joints (the joints which connect the Human mandible, mand ...
is pain or tenderness in the jaw, headache or facial ache caused by gripping the regulator mouthpiece between the teeth of the upper and lower jaws. This action is required to retain the mouthpiece in place for the duration of the dive, and may strain the masticatory muscles or the temporomandibular joint
In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral Synovial joint, synovial articulation between the temporal bone of the skull above and the condylar process of mandible be ...
, which is where the lower jawbone (mandible) hinges on the skull at the temporal bone
The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...
. This problem can be aggravated by cold water, stress, and strong water movement, and can be reduced by use of custom mouthpieces with longer and more rigid bite grip surfaces, which allow better support of the second stage with less effort.
*Leg and foot cramps
A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity. While generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the affe ...
may be caused by unaccustomed exercise, cold, or ill-fitting fins.
*Lower back pain
Low back pain or wiktionary:lumbago#Etymology, lumbago is a common musculoskeletal disorders, disorder involving the muscles, nerves, and bones of the back, in between the lower edge of the ribs and the lower fold of the buttocks. Pain can var ...
may be caused by a heavy weightbelt hanging from the small of the back, counteracting the buoyancy of the diving suit which is distributed over the full length of the diver. This effect can be reduced by use of integrated weight systems which support the weights over the length of the back on the diving harness backplate.
*Restricted circulation to the hands may be caused by excessively tight dry suit
A dry suit or drysuit provides the wearer with environmental protection by way of thermal insulation and exclusion of water, and is worn by underwater diving, divers, boating, boaters, List of water sports, water sports enthusiasts, and others wh ...
cuff seals.
Treatment
Treatment of diving disorders depends on the specific disorder or combination of disorders, but two treatments are commonly associated with first aid and definitive treatment where diving is involved. These are first aid oxygen administration at high concentration, which is seldom contraindicated, widely available, and generally recommended as a default option in diving accidents where there is any significant probability of hypoxia, and hyperbaric oxygen therapy (HBO), which is the definitive treatment for most incidences of decompression illness. Hyperbaric treatment on other breathing gases is also used for treatment of decompression sickness if HBO is inadequate. Hyperbaric treatment facilities may not be available within a useful distance of a dive site.
Oxygen therapy
The administration of oxygen as a medical intervention is common in diving medicine, both for first aid and for longer-term treatment.
Hyperbaric therapy
Recompression treatment in a hyperbaric chamber was initially used as a life-saving tool to treat decompression sickness in caisson workers and divers who stayed too long at depth and developed decompression sickness. Now, it is a highly specialized treatment modality that has been found to be effective in the treatment of many conditions where the administration of oxygen under pressure has been found to be beneficial. Studies have shown it to be quite effective in some 13 indications approved by the Undersea and Hyperbaric Medical Society.
Hyperbaric oxygen treatment is generally preferred when effective, as it is usually a more efficient and lower risk method of reducing symptoms of decompression illness, However, in some cases recompression to pressures where oxygen toxicity is unacceptable may be required to eliminate the bubbles in the tissues that cause the symptoms.In these cases other breathing gas gases such as air, nitrox, heliox, or trimix may be used.
Fitness to dive
All divers should be free of conditions and illnesses that would negatively impact their safety and well-being underwater. The diving medical physician should be able to identify, treat and advise divers about illnesses and conditions that would cause them to be at increased risk for a diving accident.
Some reasons why a person should not be considered fit to dive are as follows:
*Disorders that lead to altered consciousness: conditions that produce reduced awareness or sedation from medication, drugs, marijuana
Cannabis (), commonly known as marijuana (), weed, pot, and ganja, List of slang names for cannabis, among other names, is a non-chemically uniform psychoactive drug from the ''Cannabis'' plant. Native to Central or South Asia, cannabis has ...
or alcohol
Alcohol may refer to:
Common uses
* Alcohol (chemistry), a class of compounds
* Ethanol, one of several alcohols, commonly known as alcohol in everyday life
** Alcohol (drug), intoxicant found in alcoholic beverages
** Alcoholic beverage, an alco ...
; fainting, heart problems and seizure
A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...
activity.
*Disorders that substantially increase the risk of barotrauma injury conditions or diseases that are associated with air trapping in closed spaces, such as sinuses, middle ear, lungs and gastrointestinal tract. Severe asthma
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
is an example.
*Disorders that may lead to erratic and irresponsible behavior: included here would be immaturity, psychiatric disorders, diving while under the influence of medications, drugs and alcohol or any medical disorder that results in cognitive defects.
Conditions that may increase risk of diving disorders, but are not necessarily absolute contraindications:
* Patent foramen ovale
*Diabetes mellitus
Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...
— No serious problems should be expected during dives due to hypoglycaemia in divers with well-controlled diabetes. Long-term complications of diabetes should be considered and may be a contraindication.
*Asthma
Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...
Conditions considered temporary reasons to suspend diving activities:
*Pregnancy
Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins.
Conception (biology), Conception usually occurs ...
—It is unlikely that literature research can establish the effect of scuba diving on the unborn human fetus as there is insufficient data, and women tend to comply with the diving industry recommendation not to dive while pregnant.
Long-term health effects of diving
Decompression sickness and some barotraumas can have long term health effects, but even subclinical injuries may in some cases have long term health effects.
Dysbaric osteonecrosis is ischemic bone disease thought to be caused by decompression bubbles, though the definitive pathologic process is poorly understood. It is a significant occupational hazard, which may follow a single exposure to compressed air, and may occur with no history of DCS, but is usually associated with significant compressed air exposure. The distribution of lesions differs with the type of exposure - the juxta-articular lesions being more common in caisson workers than in divers. There is a definite relationship between length of time exposed to extreme depths and the percentage of divers with bone lesions. Evidence does not suggest that dysbaric osteonecrosis is a significant risk in recreational scuba diving.
Exposure to increased partial pressure of oxygen during diving can raise the level of oxidative stress in which increased production of free radicals can occur. The combined influence of diving-related factors on free radical production and the long-term effects on diver resilience and health are not yet understood. Diving, and other forms of exercise, can precondition individuals for protection in further dives. It is not yet known if this preconditioning can influence resilience in other environmental extremes. Cumulative exposure to high partial pressure of oxygen is known to accelerate the development of cataracts
A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision of the eye. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colours, blurry or double vision, halos around ligh ...
, a visual disorder that affects most people who live long enough. This is most likely in technical divers, saturation divers, and anyone who is treated with hyperbaric oxygen on several occasions.
The mortality rate in recreational diving is very low, and the risk of accidental drowning is unlikely to have a significant influence on the average life expectancy of divers. Risk of accidental drowning and other diving accidents can be reduced by following safe diving practices.
Permanent hearing deficits can be caused by high ambient noise levels in commercial diving, by middle and inner ear barotrauma, and by inner ear decompression sickness.
Other forms of lasting neurological damage can follow decompression sickness involving the nervous system.
A British study on former commercial divers showed a possible link between some cardiovascular disease symptoms and frequency of working dives, but it is not clear from the data whether the association is linked to diving per se or to strenuous physical activity during working dives.
There is some evidence that there are long term effects on pulmonary function from deep commercial divibg. These include accelerated reduction in lung function and development of small airways disease. There is also evidence that most scuba diving does not produce long term harm to lung function. Changes in lung function following normal scuba diving are generally small with a low chance of clinical significance, and there does not appear to be evidence of general accelerated long term loss of lung function in the majority of recreational and military divers, but there may be such effects in particularly susceptible subjects, even after relatively minor exposure.
References
{{Underwater diving, divmed
Underwater diving medicine