For the sake of your heart, better not engage in physical activity too intense after a very short night’s sleep. This is the warning of a team of scientists from Uppsala University whose study was published in the journal Molecular Metabolism. The latter started from the observation that previous studies have shown than disturbed sleep and shortened increases the risk of cardiovascular diseases, such as high blood pressure and myocardial infarction. On the other hand, physical exercise can reduce the risk of cardiovascular diseases, but it is not known whether a sleep restriction can modulate cardiac stress during intense physical exercise.
“Exercise is great for the heart, while lack of sleep has an impact on the cardiovascular system. But it’s unclear whether shortened sleep can modulate the physiological stress that intense exercise seems to have on heart cells. “, explains Professor Jonathan Cedernaes, who led the study. The scientific team was interested in a specific type of protein called troponin which is found in the muscle cells of the heart. Small amounts of troponin can be released after high intensity training, knowing that very high levels are observed in the context of cardiovascular events: it is therefore a biomarker heart damage.
A higher concentration of troponin in sleep deprived athletes
“We thought it would be important to study whether troponin release during exercise can be affected by sleep restriction. One of the reasons is the fact that many professions involve work that disrupts sleep, such as healthcare workers,” notes Professor Jonathan Cedernaes. The question therefore arises: is it possible than a lack of sleep pronounced over the long term can increase the relative risk that the heart will be injured during an intense sports session? To answer this, the researchers recruited 16 young, healthy men with normal sleep patterns who had been screened. cardiovascular diseases.
The participants were followed in the laboratory, where their meal and activity schedules were standardized. In one of the two sessions, they slept normally three nights in a row while in their other session they were kept awake for half the nights, three nights in a row. Each time, blood samples were taken in the evening and in the morning, and blood samples were also taken on the last day of the experiment, before and after a cycling session intense stationary of 30 minutes. The researchers measured two biomarkers in the blood samples including the famous protein troponin, whose blood levels increased after training.
“By making sure you get enough sleep, you increase the positive impact of physical exercise”
It turns out that for troponin, the increase after exercise was almost 40% higher after three nights of partial sleep restriction, compared to three nights of normal sleep. “The increase in troponin levels after exercise was variable among individuals. Previous research under rest conditions have alluded to such variability, it would be interesting to discover the mechanisms. adds Professor Jonathan Cedernaes. If this discovery is to deepen, the researchers emphasize that healthy people quIexercise regularly, but sleep less than the ideal amount, still reduce their risk of cardiovascular disease.
“Today, there is no evidence to suggest that it is harmful to the heartr to exercise regularly when you have had too little sleep. Instead, the argument can be reversed: by making sure you get enough sleep, you can further increase the positive impact of physical exercise. concludes the scientific team. The next step would be to further explore this risk intense physical activity on cardiovascular health in case of sleep deprivation by conducting the same experiment with specific groups of individuals. In particular athletes and soldiers, people who are often called upon to perform extreme physical performances in sleeping conditions shortened.