Deprived of sleep, the heart races from the third night
Sleeping only four hours a night for three days in a row does not seem trivial for the body. This is confirmed by a study conducted by Uppsala University, which observed the biological effects of lack of sleep on a group of 16 healthy young men of normal weight and regular sleep habits. All were placed in a sleep laboratory, where their activities and meals were strictly supervised. Two sessions were organized: one with full nights, the other with reduced nights to approximately four hours.
Each day, blood samples were taken in the morning and evening, before and after intense physical exercise for 30 minutes. The researchers then measured nearly 90 different proteins in the blood. Result: sleep deprivation caused a marked increase in many pro-inflammatory proteins. Many of these are already well known for their link to increased risks of cardiovascular diseases, such as heart failure or coronary artery disease.
Jonathan Cedernaes, lead author of the study, emphasizes: “Many large studies of the link between sleep deprivation and cardiovascular disease risk have typically focused on slightly older people, who are already at increased risk of cardiovascular disease. This is why it is interesting to find that the levels of these proteins increased similarly in younger and previously perfectly healthy people after just a few nights of lack of sleep. It is therefore essential to emphasize the importance of sleep for cardiovascular health, from an early age.”
Exercising is not enough to repair the damage of lack of sleep
The effects of physical exercise were also examined during the two sessions. A 30-minute intense exercise session was performed each day by the participants. Result: although sport induces a beneficial response by stimulating certain positive proteins, several of them showed the same level of activation, whether the subjects had slept normally or not.
“Importantly, studies have also shown that exercise can offset at least some of the negative effects of poor sleep. However, it is important to note that exercise cannot replace the essential functions of sleep.”warns Dr. Cedernaes.
Researchers had already highlighted in previous work that sport practiced in a state of sleep deprivation could lead to an increased load on the muscle cells of the heart.
How to preserve your sleep (and your heart)
Although the results are alarming, the study has significant limitations: it only concerns a small group of 16 young men, which prevents generalizations to the entire population, particularly women, the elderly or those already suffering from sleep disorders.
Still, the lessons are clear enough to encourage better sleep hygiene, especially at an age when we often think we can “recover later”. To preserve your heart:
- Set regular bedtimes and wake-up times, even on weekends;
- Reduce exposure to screens at least an hour before bed;
- Sleep in a cool, dark, quiet room;
- Avoid coffee and alcohol in the evening;
- Do sport, but never as a substitute for good rest.