American scientists have proposed a new metric of sleep quality – a “sleep regularity index” that takes into account sleep time, sleep and sleepiness, and daylight exposure. The researchers found that irregular sleep increases the risk of developing cardiovascular and metabolic diseases, regardless of its duration. The article is published in the journal Scientific Reports .
The dream of modern man is regulated by two parameters. Firstly, these are circadian rhythms, that is, the internal change of day and night every day. Because of the abundance of artificial lighting and the need to do work and engage in other activities during the night, the individual needs of the body also affect sleep. Unfortunately, most of the research on the influence of sleep on human health is most often guided by one, the most important parameter, the duration of a night’s sleep, but does not take into account possible breaks for sleep during the day, as well as (not less importantly) the time to bed. This, however, may be ineffective: studies show that daytime sleepiness is associated with an increased risk of developing neurodegenerative diseases, and late sleep decay is associated with the risk of developing mental disorders.
Sleep studies, therefore, can be better if other parameters of rest are taken into account, according to scientists from the Duke University Medical Center under the leadership of Jessica Lunsford-Avery. In their article they suggested taking into account the time of going to sleep and recovery, the periods of physical activity and the impact of daylight: these data were collected with the help of smart clocks worn by 1978 participants of the study (the average age was 68.7 years). Participants also provided data on their physical health, bad habits, their demographic data and told how often they feel sleepy during the day.
The collected information on sleep and activity of participants was used to calculate the “regularity index of sleep” – a number from one to one hundred, indicating the likelihood that a person goes to bed and gets up at the same time. Scientists have found that irregular sleep was associated with late sleep, reduced exposure to light and increased sleepiness during the day, but did not have an association with the duration of sleep.
Then the authors studied how the regularity of sleep is associated with the risk of developing various diseases. It turned out that those people, whose period of night rest occurs at different times, is several times higher than the risk of diabetes, obesity, heart failure, hypertension and other metabolic diseases and diseases of the cardiovascular system.
Scientists, thus, note the importance of timely retirement and insist that go to bed and get up better at the same time. At the same time, they also emphasize the importance of taking this parameter into account in studies of the effect of sleep on human health.
Short-term sleep disorders can also negatively affect health. For example, in the spring, scientists found that increasing the number of beta-amyloids in the brain, indicating a high likelihood of developing Alzheimer’s disease, can only one sleepless night.