Maintaining a regular sleep schedule can help prevent cardiovascular disease

Different investigations published in recent years have already linked lack of sleep with the development of various cardiovascular conditions, including hypertension, type 2 diabetes and heart disease. According to data from an important meta-analysis presented at the last meeting of the American Heart Association and published in the scientific journal Clinical Cardiology, insomnia and sleeping less than an average of five hours are associated with significantly higher rates of myocardial infarction. The link between the two is comparable to that of other risk factors, such as high blood pressure and cholesterol.

Indeed, last summer, the American Heart Association added sleep to its cardiovascular health checklist, which includes diet, physical activity, nicotine exposure, blood pressure, body mass index, blood lipids and blood glucose. Sleep positively affects other factors, such as diet and physical exercise. This was shown in another recent study presented in early March at the 2023 Scientific Conference of the American Heart Association. According to that study, people with better sleep quality have a greater ability to stick to their diet and exercise plans while trying to lose weight.

“In the end, it’s a fish that bites its own tail,” says Dr. María José Masdeu, pulmonologist and head of the Sleep Unit at Hospital Universitari Parc Taulí in Spain, who points out that poor-quality sleep ends up encouraging worse health habits. “Sleeping poorly increases the risk of obesity, since the presence of leptin in our body decreases, which is the hormone that makes us feel full, while the presence of ghrelin increases, a hormone that increases the feeling of hunger and that leads us to the fridge to eat things rich in fats and refined carbohydrates, generally speaking. In other words, if you sleep little you will tend to eat worse and on top of that you will not feel like doing physical exercise.”

Having confirmed the relationship between poor rest and cardiovascular health problems, a recent study published in the Journal of the American Heart Association has gone a step further to try to better understand the links between lack of sleep and an increased risk of cardiovascular disease. The results of that research suggest that maintaining regular sleep schedules and sleeping approximately the same amount of time each night may play an important role in preventing cardiovascular disease. “In our study we found that participants who slept a variable number of hours throughout the week [meaning less sleep one night, more sleep one night, etc.] and who did not follow regular sleep schedules were more likely to have atherosclerosis than participants who slept approximately the same amount of time each night,” Dr. Kelsie Full, a researcher at the Vanderbilt University Medical Center (USA) and lead author of the study, tells EL PAÍS.

Atherosclerosis is defined as the hardening of the arteries due to the accumulation of fat, calcium, cholesterol and other substances in the artery walls. “It is the vascular disorder that is behind all the problems that we see later in the hospital, such as heart attacks, strokes, etc.” says Dr. Javier Mora Robles, a cardiologist at the Regional University Hospital of Málaga in Spain and a member of the Spanish Society of Cardiology (SEC), who describes the research as “impressive.” “It is a very well done study that, for the first time, demonstrates with imaging tests and a well-carried out sleep study, how irregularity in sleep duration and sleep schedules are clearly related to the development of atherosclerosis.”

Masdeu agrees, pointing out that the study “clearly” shows that the more irregular the sleep is and the longer this irregularity is maintained, “the more damage appears in the vascular system and, therefore, the greater probability there is of developing this type of disease.”

As Dr. Kelsie Full explains, all cardiovascular functions, including heart rate, blood pressure and endothelial functions, are controlled by the circadian clock. Variation in sleep patterns — including when we go to sleep and the total amount of sleep — can throw off our circadian clock, and with it, these important cardiovascular functions, “making it harder for the heart to rest and recover, which is an important function of sleep.”

“The study shows very well the biological way in which the damage is caused,” adds Dr. Masdeu. It’s a chain reaction: poor sleep prevents the vascular system from doing its restoration work, which encourages the increased buildup of deposits on the walls of the arteries. “If we add bad habits, such as an unhealthy diet or lack of physical exercise, to these small accumulations of fat, calcium and cholesterol derived from poor sleep, the plaques will grow larger and end up clogging the artery.”

“This study shows that sleep is an essential health element at all levels and that it is something that we must promote from medical centers up, since good sleep hygiene can prevent the advent of cardiovascular problems,” says Javier Mora Robles.

Masdeu offers two pieces of advice on how to prevent cardiovascular disease: improve sleep hygiene and exercise, preferably in the morning, to synchronize the circadian rhythms with the environment. “You have to always try to sleep the same hours and at a fairly similar time every night, taking special care on the weekend to try to avoid what we call social jet lag [the delay in going to bed and waking up during holidays],” he says. “With these two tips, we are taking an important step to improve our sleep and protect our cardiovascular health.”

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