The importance of Adaptation

The importance of Adaptation

Unlike scuba diving which involves an oxygen tank, freediving involves the act of holding a single breath while you deep-sea dive without that external supply of oxygen. Before the 19th century freediving was the only way to dive as business-minded people worldwide searched to profit from seafood and pearl collecting, treasure hunting and sponge harvesting. In Japan for example, there were over 13,000 freedivers, also known as the Ama people or sea women, still practicing today’s recreational sport in the early 90’s.

As early as the 1920’s, the Ama people, studied freediving human adaptations measuring diving patterns, seasons and equipment. Today, while freediving is still considered by many as an extreme sport, with people looking to surpass world records in breathe holds and deep dives, it is slowly making it's way into a mainstream activity safely practiced by many freedivers worldwide. Did you know Austian Herbert Nitsch holds the current world record for freediving at an incredible depth of 830 feet in 2012? Freediving in spectacular destinations like Pompano Beach really pushes your body and mind to their limits, so there are a number of adaptations to consider including thermal, respiratory and cardiovascular responses.

Freediving Thermal Adaptations

When freedivers submerge themselves in cold water temperatures without wet suits, their bodies adapt just like people who live in cold environments. Thanks to the “mammalian diving reflex” which optimizes respiration for staying underwater for a longer time, if you dive into water, you’ll feel your pulse rate starting to slowdown (also known as bradycardia). The average human pulse rate typically decreases by up to 30%, but with freediving experience it can decrease even more. This thermal adaptation allows humans to preserve oxygen reserves by limiting oxygen consumption.

The mammalian diving reflex allows freediver to stay underwater longer and dive deeper.

Freediving Respiratory Adaptations

Respiratory adjustments are another adaptation to consider underwater which develop over time as freedivers practice control over their breath. Respiratory tolerance of the carbon dioxide buildup, various gas flows exchanges and an increase of lung volume capacity are all as adaptations. If you inhale and refrain to breathe, the space between your vocal chords closes and you’ll feel a slight pressure on your lungs which intensifies until your diaphragm contracts due to the carbon dioxide buildup.

A seasoned freediver is able to ignore their body as it fights back to breathe. Their tolerance increases above normal and willpower kicks in. Through various training such as packing their lungs with short and rapid inhales as well as unpacking for equalizing ear and lung pressure, freedivers are able to increase their breath hold and lung volume over time.

Freediving Cardiovascular Adaptations

Diving response and the innate animalistic ability to survive underwater are what make up the cardiovascular changes in freedivers. These innate responses include a deceased heartbeat, increased blood pressure and reduced blood flow to organs and muscles, all in the goal of conserving oxygen. The most prominent diving responses are in colder water, and in freedivers who are younger and healthier.