Irregular sleep at night increases the risk of heart attack or stroke, while drowsiness in the elderly during the day may indicate the onset of a new condition.

People who sometimes sleep a lot and sometimes little and those who go to sleep at very different hours, face a greater cardiovascular risk. The more irregular the duration of their sleep, the greater the risk of developing cardiovascular disease seems to be due to a disturbance of the biological clock that affects metabolism, blood pressure and heart rate, according to a new U.S. scientific research.

The researchers, led by Assistant Professor of Sleep Epidemiology Tianyi Huang of Harvard Medical School and Brigham & Women’s Hospital in Boston, who made the relevant publication in the journal of the American College of Cardiology, studied over five years almost 2,000 people 45 to 84 years old. Participants did not have cardiovascular disease at the beginning of the study and were asked to wear a special sleep recorder on their wrist. During the research, 111 people suffered a heart attack, stroke or other cardiovascular attacks.

It was found that those who had the most irregular sleep (deviation of at least two hours during sleep each night), were more than twice as likely to have a cardiovascular problem. Those who had the most normal sleep schedule (deviation of up to an hour from night to night), were less at risk. The same difference in risk existed in terms of the deviation of the time one fell into bed to sleep: those who differed by at least 90 minutes from night to night, they were more at risk than those who differed by at most 30 minutes.

“Usually when we talk about sleep, we tend to focus on its duration, on how many hours one sleeps in the evenings and not on how irregular your sleep is, how naughty hours falls into bed and how much does the duration of his sleep differ from one night to the next. Our study shows that healthy sleep is not only adequate sleep, but also one that is not irregular,” said Dr Huang.

Another US study, led by Dr Nour Makarem of Columbia University College of Medicine in New York, conducted on 1,920 people with an average age of 69, confirms that if all three are combined – adequate sleep, quality sleep at regular intervals – then the risk of heart attack, stroke and other cardiovascular problems is reduced.

At the same time, this helps, especially women, in maintaining a normal weight. Those who fall asleep at the same time every night, lose weight more easily.

There is growing evidence that little, bad and irregular sleep increases the risk of heart disease, hypertension, diabetes, obesity, etc. In fact, several scientists argue that sleep should now be considered the eighth marker of cardiovascular health evaluation, along with smoking, body weight, diet, physical exercise, cholesterol, blood pressure and sugar level.

The second research found that people with the healthiest sleep duration (seven to eight hours each night) are 61% less likely to be diagnosed with a heart problem. Those who sleep qualitatively and not irregularly have a 59% lower risk of heart attack or stroke and a 44% lower chance of developing heart disease within the next five years.

Finally, a third American study, led by Dr Maurice M. Ohayon of Stanford University, California, which was done at nearly 11,000 people and presented at a conference of the American Academy of Neurology in Toronto, came to the conclusion that older people who experience daytime sleepiness, can are more at risk of new conditions, such as diabetes, hypertension or cancer. This applies especially to those elderly people who are sleepy during the day, even though they have slept at least seven hours at night.

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