UPPSALA, Sweden — Exercise keeps your heart pumping, but if your chest feels tight or painful, your body is warning you to take it down a notch. However, researchers from Uppsala University suggest that heart problems while working out could also be a sign your body needs more sleep.
Regular exercise can reduce your overall risk of developing heart disease. However, not sleeping for the recommended seven to nine hours could counteract these effects in the long run. Before this study, there was little data to explain how not sleeping enough could impact the stress intense exercise has on the heart.
“Those who report exercising on a regular basis, but get less sleep than the ideal amount, still reduce their risk of dying from cardiovascular disease. At the same time, we know that chronic or recurrent sleep disruption is bad for cardiovascular health. It is therefore possible that a more pronounced lack of sleep in the long run can increase the relative risk that the heart is injured in some way by more intense exercise. But many individuals experience a temporary lack of sleep, and the need for sleep is also very individual,” says Jonathan Cedernaes, physician and associate professor of medical cell biology, in a university release.
The study focused on changes to a protein in heart muscle cells called troponin. The body releases low amounts of troponin after high-intensity training. However, even higher levels of troponin could lead to acute cardiovascular events.
2 blood biomarkers appear after intense workouts
Researchers tracked the heart health of 16 young men with normal weight and no history of health issues such as heart disease. All participants reported getting seven to nine hours of sleep a day.
In one session, participants could sleep for this long for three consecutive days. However, in the next session, participants stayed awake for half the night for three straight days.
Study authors collected blood samples every evening and morning during the experiment. After both sleep sessions, the team took blood samples before and after 30 minutes of long intense stationary cycling.
Blood analyses detected two biomarkers: NT-proBNP and troponin. NT-proBNP is a sign of a heavy load on the heart. Troponin is a marker for cardiac injury.
The researchers observed higher NT-proBNP levels during exercise. The increased amounts did not change depending on whether participants got a full night’s rest or not.
Troponin levels also increased after a workout. However, troponin levels were 40 percent higher during high-intensity exercise after participants had a partially sleep-deprived night.
“An important observation was that the levels of troponin and NT-proBNP were not elevated in response to sleep restriction at any time prior to the workout. It is possible that lack of sleep may instead lower the threshold at which an increased exercise load results in measurable stress in heart muscle cells, as may occur in response to strenuous exercise,” Dr. Cedernaes explains.
“However, we noted that the increase in circulating troponin levels following exercise was variable across individuals. Previous research under resting conditions has also hinted at such variability, and it would be interesting to uncover the mechanisms.”
The research is published in the journal Molecular Metabolism.