Is Holding Your Breath Safe?

Human lungs are not capable of pulling in air themselves. Instead, the diaphragm contracts and moves downward to increase the available volume in the chest. Humans can force themselves to breathe using certain accessory muscles. The lungs then inflate, allowing air to enter and fill air sacs called alveoli. Oxygen from the air in the alveoli can then pass to the blood vessels while carbon dioxide moves into the alveoli from the blood vessels. Oxygen-rich blood then travels to the heart, which pumps it throughout the body. To exhale, the diaphragm relaxes along with the intercostal muscles. This contracts the lungs and forces out air rich in carbon dioxide.

Many bodily effects occur when a person holds their breath. The exchange of gases between the alveoli and the blood is completely independent of any movement of air to or from the lungs. Even while performing voluntary apnea, there may be enough stored oxygen to supply the blood vessels for a short period. The body releases less carbon dioxide in comparison to the oxygen it absorbs, which can cause a gradual collapse of the lungs. Additionally, the body cannot release carbon dioxide without breathing, and the blood will begin to load itself with carbon dioxide. Hypercapnia or too much CO2 in the blood can lead to respiratory acidosis, which can cause headaches, restlessness, and confusion.

Many cultures and individuals believe voluntary apnea has beneficial effects on the body and the mind. Some people find deep breathing exercises and breath-holding help them overcome issues such as anxiety or stress. Additionally, breath-holding exercises help train the body and increase lung capacity. Many athletic activities, such as freediving, require extreme lung capacity. Additionally, some athletes perform voluntary apnea exercises and training because they believe it has positive effects on their performance. However, there is very little available research on this topic and related studies paint a generally negative picture of breath holding.

Researchers associate various risks with breath holding. The primary issue, hypoxia, occurs when the body does not receive an adequate supply of oxygen. This can affect the body as a whole or individual regions such as the hands or feet. Often, hypoxia occurs in athletes during voluntary apnea training or altitude training at extreme heights. Breath holding can also lead to other issues such as elevated blood pressure, sleep apnea, and possible brain damage.

Because voluntary apnea is common among breath-hold divers and freedivers, multiple studies attempt to quantify the effects of breath-holding in these individuals. One such study featured nine competitive breath-hold divers and six other individuals who had minor experience with breath-hold diving. The study found that seven of the nine competitive divers had significantly higher levels of the marker for brain damage, S100B. This protein is most present in people with neurological disorders such as Alzheimer’s disease and Down’s syndrome. Though the divers did not present high enough levels to pose a direct risk, researchers note that the practice of voluntary apnea could eventually lead to significant brain damage. However, more studies focusing on the long-term effects of breath-holding are necessary to draw real conclusions.

One of the most common misconceptions about breathing and holding your breath involves hyperventilation. Many people, most notably athletes, believe that quick, short breaths before exercise improve the body’s ability to hold oxygen. In reality, hyperventilation tricks the body into believing -- wrongly -- that it no longer requires as much oxygen. Though hyperventilation may slightly improve a person’s ability to hold their breath by suppressing the body’s desire to breathe, it comes at a higher risk for hypoxia. In some cases, it can even lead to loss of consciousness.

Most people can only hold their breath for around a minute or two. Particularly fit individuals can typically hold their breath for longer than most because frequent exercise conditions the body to use less oxygen and produce less carbon dioxide. However, almost anyone, including athletic individuals, will struggle to hold their breath for longer than a few minutes. Only professionals who frequently perform lung capacity exercises can hold their breath for longer. Additionally, the presence of water suppresses the body’s urge to breathe, particularly when a person submerges their face. The current world record for static apnea, or breath-holding while floating stationary in the water is upwards of 12 minutes.

Athletes and competitors use many exercises to improve their lung capacity and reduce the amount of oxygen their bodies require. Some, such as breathing exercises, are simple. Diaphragmatic breathing requires a person briefly inhale and feel the air move into the abdomen, moving their diaphragm. They briefly exhale while pressing on the abdomen, and repeat. Other methods to improve lung capacity include apnea training and altitude training.

Though it is less common for dry land sports, many divers and surfers practice apnea training to improve their lung capacity and increase the amount of time they can hold their breath. Primarily, apnea training begins with basic breathing exercises and learning the proper methods of breath-holding. Then, while holding their breath, athletes practice aerobic and anaerobic exercises such as running and weightlifting respectively. One study found that apnea training reduced the risk of blood acidosis. Additionally, though apnea training was more likely to lead to hypoxia, it also increased the tolerance to hypoxic conditions. However, it is possible that long-term apnea training damages the brain’s safety mechanism for maintaining a proper balance of oxygen and carbon dioxide.

Altitude training is another method many people use to reduce their body's reliance on oxygen. An individual performs normal exercises in areas with higher elevations than normal. Because air at higher elevations contains a lower concentration of oxygen, the environment forces the body to become more oxygen-efficient. However, despite its benefits, altitude training has risks. Notably, it carries an increased risk of hypoxia. Also, once the athlete returns to normal sea level, their immune system may be much weaker, and they could develop long-term blood pressure elevation.