The study of a freediving champion's brain is a fascinating example of physiology in extreme conditions. The brains of freedivers show remarkable physiological responses, including severe cardiovascular suppression. Freediving is known to be dangerous and also affect short-term memory and heart rate. Read on to find out if freediving harms the human brain. We hope that the research will shed some light on the controversial question, "Can freediving damage the human brain?"
An MRI scan of a competetive freediving world champion's brain may reveal the cause of the athlete's numbness and difficulty holding breath. Guillaume Nery, a 35-year-old French freediving champion, has been undergoing training for more than 20 years, racking up numerous world records. A new study has revealed that the sport's intense training and thousands of freedives do not cause any brain damage.
MRI scans of freediving champions show that they have developed extraordinary adaptive capacity to extreme conditions. This is reflected in the fact that they endure cardiovascular suppression and can tolerate extreme conditions, such as hypoxia. MRI scans of freediving champions showed altered connectivity in the pre and postcentral cortices, as well as a significant increase in alpha and delta band connectivity. In addition, fMRI showed altered somatosensory integration.
In 2000, a group of free divers in Canada approached pulmonologist Ralph Potkin and described their attempts to expand their lung capacity beyond normal limits. They claimed to be able to do this by performing deep breathing exercises and a technique known as "glossopharyngeal insufflation". Unfortunately, the technique was only studied in the context of recovering lost lung function in people with spinal cord injuries.
During a dive, freedivers have to maximize their oxygen consumption, or output, to maximize their performance. Fortunately, this requires low energy output, which makes freediving possible for long hours at a time. By practicing a rhythmic breathing pattern, freedivers can learn to increase their ability to maintain an air supply. The physiology of extreme breath-holding in freedivers is explained in detail below.
The effects of freediving on the short-term memory of athletes are unknown. One study tested 21 people and found that it increased certain biomarkers associated with brain damage. The biomarkers T-tau and Ab42 were increased. The study also found that the practice of freediving induced transient hypoxia, causing a mild neurological effect. However, more research is needed to determine whether freediving really affects the brain.
The effects of freediving on the short-term memory of athletes was investigated in a recent neuropsychological study that included elite freedivers, beginners, and university students who had never freedived. The elite athletes were found to perform worse on memory tasks compared to the non-freedivers, which suggested that long-term intensive freediving may cause some mild memory issues. However, this study did not find any conclusive evidence that freediving impacts long-term memory.
One of the most important questions in the cardiovascular system is what happens when a freediver goes under the water and holds his breath for four minutes or more. In a recent study, researchers from the University of Bonn and the University of Cologne studied the effects of freediving on the heart rate of elite freedivers. They conducted cardiac MRIs and carotid artery MRIs on each of the subjects, who were then compared to their control group.
In a study of more than a hundred divers, their heart rates were very high before diving and rapidly fell by approximately 80% once they entered the water. The percentage reduction by immersion varied among participants, but the decrease was consistent across subjects. It also appeared that the bradycardic dive response was not affected by age or gender, which suggests that it is independent of age. Nonetheless, it is important to know your cardiovascular risk level before freediving, because subsequent coronary events are more likely to occur while you're under water.
Cardiovascular and respiratory changes in elite freedivers are consistent with biphasic decrease in cardiac output and increased HR. However, the latter might be due to simultaneous activation of the exercise and diving responses. Nonetheless, there are potential implications for the practice. The biphasic decrease in HR may indicate that the physiological state of freedivers is similar to that of elite freedivers during a high-intensity session of scuba diving.
Freedivers also experience changes in spleen function. This organ, shared by the liver, serves a secondary function: to destroy old blood cells. However, it can help freedivers when the blood shift occurs, as it acts as a reservoir. In addition to acting as a reservoir for extra blood, it releases the extra blood during the blood shift, which means there are more red blood cells carrying more oxygen.
Studies have shown that the elite athletes in freediving have brain oxygen levels as low as seals and whales. This may have to do with their heart rates - the elite divers have been known to dive as deep as 107 meters. The findings, however, could be valuable for the treatment of cardiac patients. Scientists are currently working to develop new procedures to improve brain protection during surgery. But they also need to learn more about freediving.
The first study found that the effects of freediving on the brain were not permanent. Overbreathing reduced the blood's carbon dioxide content, which led to a diminished urge to breathe. This could have led to a blackout from lack of oxygen. Furthermore, hyperventilation increased heart rate and oxygen burning. In addition, it also lowered blood flow to the brain. Finally, oxygen bonds more strongly with hemoglobin, which made it harder for the brain to access oxygen.