If your lungs hurt after freediving it’s important to find out why. If your lungs feel uncomfortable after practicing apnea exercises in or out of the water, but you have no other symptoms, take a rest, and try again another day. As you become stronger and more experienced, this discomfort may lessen.
If your lungs are in pain and you are experiencing other symptoms including coughing blood, wheezing or feeling weak, you need emergency medical attention and should return to shore and find a hospital as soon as possible.
Lungs should not generally hurt after freediving but there are several reasons why they might. Being unused to apnea (breath-holding) might cause lung discomfort in beginners but this should not be serious if they build up timing and depth gradually. Lung squeeze, on the other hand, is a serious and painful freediving injury and requires quick medical attention.
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If you’ve recently started freediving, or you’ve been reading about freediving, you might want to know why freedivers sometimes report feeling pain or soreness in their lungs after freediving. Our article tells you more about the benefits and risks of freediving for your lungs, as well as its physical impacts on the body.
Is freediving good for your lungs?
Freediving can be good for your lungs if you train thoroughly, practice regularly and increase the depth and timing of your dives gradually. However, it also places a unique set of stresses on the body’s cardiopulmonary system. If you want to know the detail, we’ve written a whole article on why freediving is good for your lungs here (opens new tab).
Risks to the health of freedivers’ lungs include rising hydrostatic pressure, low blood oxygen (hypoxia) and high blood carbon dioxide (hypercapnia). Untrained freedivers, freedivers with pre-existing lung conditions, or smokers, may all be at increased risk of harm to the lungs.
Practicing freediving breathing techniques and apnea (breath-hold) exercises can increase lung function and capacity (e.g. learning to fully exhale during the breath-up preparation before a dive will help reduce residual lung volume, allowing the lungs to take in more air on the final breath before descent).
These improvements can be realized and measured even in those who are already very fit when they begin freediving training. Elite athletes who undertook freediving breath training reportedly saw an increase in lung function of 10%.
What happens to your lungs when you freedive?
Spending time deep underwater while freediving can exert massive pressure on a diver’s body, including the lungs, even at depths only a few meters below the surface. By 10 meters depth, water pressure will be double the pressure normally felt on land at sea level. Water pressure will then increase by the equivalent of a full atmosphere for every further 10 meters a diver descends.
With increasing water pressure, gas volumes in the body’s airspaces (lungs, ears, sinuses) decrease in inverse proportion, following the relationship of Boyle’s Law. When a diver is 10 meters below the surface, the volume of their lungs will be reduced by 50%, and can fall much further. During the deepest dives, a freediver’s lung volume could be less than a quarter of their surface size.
Under high pressure, the chest cavity is compressed and blood collects in the chest area from surrounding tissue, having been being diverted from peripheral body parts and towards the vital organs including brain, heart and lungs. This mechanism decreases the effective residual volume of the lungs and allows them to be compressed as far as 5% of normal lung capacity in elite competitive freedivers.
Once ascent towards the surface begins, lungs and other airspaces expand again. To learn more about the effect of freediving on the lungs, check out our full article on what happens to lungs when feeediving (opens new tab).
Can diving hurt your lungs?
If you are healthy, well-trained and following key safety guidelines, your lungs should not normally hurt when freediving. At the same time, lung pain is not unusual and there are several common explanations.
For beginners, simply learning to hold the breath for long periods might cause some discomfort or pain. Static apnea exercises on land or in shallow water can help develop a tolerance for breath-holding, and help make chest muscles and ligaments strong and supple.
Once in the water, compression of the lungs under high water pressure could feel uncomfortable or painful to someone unused to the experience. Depth of dive should be increased gradually over time, allowing a freediver’s body to become accustomed to the demands and sensations of such high pressure.
While descending or ascending we need to be able to equalize the gas pressure in our airspaces with the water pressure around us. If we don’t do this (e.g. diving too quickly) or can’t do it (e.g. congested nose or sinuses prevent equalization of the ears) this can cause different kinds of barotrauma (pressure injury).
Damage to the body caused by barotrauma is generally called a “squeeze”. “Lung squeeze” can be a painful and serious injury and an affected diver should seek speedy medical attention.
What is lung squeeze in freediving?
Lung squeeze is a type of injury which is found almost exclusively among freedivers. It is also sometimes referred to as “chest squeeze”, or called by its correct medical name: pulmonary barotrauma of descent (PBT).
PBT occurs when high water pressure impacts the lungs during a freedive. This generally happens when a freediver’s depth means that their lungs reach residual volume (around 20-25%) – approximately between 30-45m. Cases of of lung squeeze have also been reported following multiple shallower dives with short surface recovery intervals.
As lung squeeze is not found in every freediver after after deeper dive, further physiological mechanisms must also play a role in triggering PBT. As with many other areas of freediving science, the exact pathophysiology of lung squeeze is not fully explained and more research is needed.
What does lung squeeze feel like?
Increased pressure on blood vessels in the lungs under high water pressure can cause damage to capillaries in the lungs, leading to rupture and leakage of blood and fluid. Affected divers may show the features of pulmonary edema or hypoxemia. Remember that can lead to secondary drowning, where blood (rather than water) floods the lungs and prevents oxygen uptake.
Lung squeeze symptoms can include:
- severe coughing and/or coughing up blood
- wheezing
- shortness of breath
- chest pain or tightness
- weakness and fatigue.
How do you recover from a lung squeeze?
If you or another freediver have suspected lung squeeze then you need to take action quickly. The diving session should end immediately so that the injured diver can safely get to shore and access medical help. Where possible, the diver should be given 100% oxygen to breath. If they remain fully conscious and there is no obstruction to their airways, they should also be given fluids to drink.
Emergency medical evaluation and treatment is advised for lung squeeze symptoms, and evaluation by a specialist diving physician would be ideal. Doctors will normally deploy escalating phases of treatment according to the severity of the case and how quickly symptoms are progressing.
Once any hospital treatment is completed, a freediver with PBT will need to rest for days, weeks or however long it takes for all pressure injuries in their lungs to heal.
Freedivers can reduce their risk of developing PBT with measures including training to develop chest and diaphragm flexibility, maintaining a good posture, and keeping to safety guidelines on diving depth and surface recovery time.