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Working out and scuba diving

Everything scuba divers need to know to stay fit and safe underwater


Preparing for a scuba diving adventure involves more than just packing your gear and checking the weather conditions. Being mentally and physically ready is an important part when facing your scuba trip. For scuba divers, staying fit can offer numerous benefits, such as increased stamina to help in the most challenging environments, improved cardiovascular fitness which can lead to extended bottom times, and enhanced overall performance that can assure readiness in order to overcome the unexpected and reduce the risk of decompression sickness (DCS).


Physical fitness can be maintained by exercising within our body´s capacity limits three or four times a week for about 45 minutes. Most divers will find this type of workout sufficient for an active recreational scuba diver´s yearly schedule. However, physical fitness can be enhanced when the workout exceeds our body´s current capacity and a progressive training is put into motion.


As active scuba divers, it is essential to approach working out during a diving trip with caution to ensure our safety and reduce the inherent potential risks of decompression illness (DCI). The way of doing this is by planning your workout routine around your diving schedule. To do this, we will need to understand the reasons why working out can reduce or increase the risk of DCI, the moment that workouts should be done and the workout intensities recommended.

yoga on the beach before scuba diving

The relationship between working out and bubble formation

As we know, while scuba diving, when we breath air, Enriched Air (EANx) or even Trimix, part of the gas we inhale is nitrogen (N2). N2 is an inert gas which is not used by our bodies and the part of it that is not exhaled gets stored within our tissues. We call this process on gassing and it happens mainly while we descend and during our bottom time during a dive.


The objective of safety stops, slow ascents and correct decompression procedures is to eliminate the excess of nitrogen dissolved in our tissues in a slow safe way, preventing harmful bubble buildup that can lead to DCI. This process is called off gassing and in great measure, it starts underwater as we ascend and continues further on over time after we surface.

While formation is not the same as DCI, the amount and size of them present in our bodies can increase or reduce a diver´s decompression stress. In fact, very small harmless bubbles are generally always present, even after a shallow dive, these are called silent bubbles. A full decompression, depending on the N2 saturation levels achieved during the dive, can last as long as 48 hours.

Physiological or mechanical effect

Wether the bubble formation is a physiological or chemical effect is still not clear. However, it is accepted that N2 bubbles form around micronuclei. These are small bubble precursors attached in our blood vessels which grow into actual bubbles with ambient pressure reduction. The number and location of micronuclei is related to blood circulation efficiency, muscle contraction and tissue movement particularly along the joints and, it increases with strenuous workout. Therefore, the N2 bubbles buildup is magnified by the amount of micronuclei existent in our tissues before a dive and can potentially increase the risk of DCI.

A diver should not perform strenuous workout sessions 24 hours or less prior to a dive

Recent research has thrown to light that exercise like weight lifting, hard running or strenuous hiking or swimming before a dive should be avoided only during the six to four hour window prior the dive. The recreational diving industry consensus suggests that window to be extended to 24 hours. While impractical, this industry rule of thumb has proven itself for years. The conservatism it proposes greatly reduces the presence of micronuclei before scuba diving. Research proving that heavy workout sessions closer to diving have little or no effect in decompression stress were put into practice on highly trained subjects and, should not be applied to normal recreational divers yet.


On the other hand, studies have revealed that moderate aerobic exercise that does not involve heavy weight lifting, putting pressure on the joints and rapid intense movements 24 hours before and after diving can improve divers on gassing and off gassing process. This lighter activities enhance blood flow and heart pace without the extreme oxygen use, raised blood pressure and body temperature increase that strenuous workouts produce.


Exercise that can deplete the formation of venous gas bubbles before diving include yoga, stretching, moderate walks and swims. These workouts inhibit the micronuclei activity, reducing bubbles formation and decompression stress, and assisting with the off gassing process.

man streatching before diving

Improving our decompression underwater

Strenuous workout during diving not only has decompression implications. It increases the risk of overexertion that can lead to carbon dioxide buildup and it should be avoided. Strenuous workout during diving, particularly during compression (descents) and bottom times, is directly related with three main factors besides our own fitness:


  • The environmental condition in which we are diving in, can push our physical abilities to the limit. Diving in strong currents, for example, can lead to a strenuous dive which will increase the on gassing process as we work harder and harder, therefore increasing our decompression stress. It is always recommended to dive within our own training limits and capacities.

  • Our mental state is also directly related with the effort we exert during diving. The lack of confidence can create an over-pressure on our physical performance. Considering our mental fitness prior to a dive is also part of a responsible diver´s behavior.

  • Our diving technique, if poor or lacking, can lead us to work hard underwater. Carrying too much lead or having an inefficient trim position for example, can lead to physical stress. Staying up to date with your technique and keeping on learning and improving, are all divers responsibility.


All three factors can generate an excess of workout underwater, having a detrimental effect on the on gassing and off gassing process and increasing our decompression stress. On the other hand, light exercise during safety or decompression stops have proven effective to assist in decompression. These moderate activities slightly increase blood circulation, improving the off gassing process. The cautious consideration to take into account during this procedure is, how much and how moderate these workout should be.

After diving behaviour

After diving behavior should also be considered to improve our off gassing process. Intense physical activity immediately or shortly after diving can boost decompression stress and the risk of DCI by accelerating our heart rhythm and blood flow, expediting N2 release. In addition, sleeping right after diving will decrease our blood circulation slowing the off gassing process.


It is recommended that after diving, the diver engages in moderate physical activities such as walking or moderate swimming. This exercise will improve the off gassing without enhancing the decompression stress over the tissues.

The best course to follow

As theories about the correlation between workout and decompression stress and DCI are still being tested on animals and highly trained human subjects, it is not possible to determine exactly what course the average recreational diver should follow. Even though less conservative procedures may work for some, the term recreational diver involves a wide range of people of different ages and fitness conditions among other characteristics. Is due to these facts that recreational divers should rely on the most conservative measures to remain within acceptable safety parameters.


The general recommendation to avoid strenuous workouts within the 24 hour window prior and after a dive should be accounted for until more research is done and new statistics are analyzed, closer to the average recreational diver. Keeping yourself fit and up to date with your diving technique will help you improve your inert gas exchange process during and after a dive and reduce your decompression stress. Being a responsible diver and diving within your own training limits and capacity will boost your confidence and let you gain experience for further and more challenging dives. STAY SAFE AND ENJOY YOUR DIVING!

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