During freediving, apnea is the suspension of breathing. Unlike diving where you have to hold your breath for a short period of time, apnea in freediving involves longer breath-holds. The purpose of apnea training is to condition your body to extend the time it can be in a hypoxic environment.
During apnea, your heart rate decreases as arterial blood reaches your brain. This lowers your heart rate in order to compensate for the change in pressure. If your heart rate increases during apnea, you will burn more oxygen.
Hypoxia tolerance, or the ability to maintain normal mental function in low oxygen levels, is an important skill for many people. Having this skill is also helpful for firefighters and other people who are exposed to high pressure environments.
A growing body of scientific research shows that apnea training can help with hypoxia tolerance. This is because the cardiovascular “diving response” is a metabolic response that limits myocardial oxygen consumption. This response reduces peripheral circulation and increases SpO 2. The goal is to develop hypoxia tolerance and reduce the risk of cardiovascular disease.
Apnea training is also helpful for improving hypercapnia tolerance. Hyperventilation is a voluntary increase in breathing rate. Hyperventilation can be a fine practice on the surface.
Aside from breathing, apnea is also used for relaxation. Relaxation can be achieved through a combination of meditation, diet, and equipment. When practicing relaxation, make sure you do it in a safe location and with a friend.