Lack Of Sleep More Dangerous For Women Than Men

By Margarita Nahapetyan

Getting less than eight hours of sleep at night could be far more dangerous for women than men, increasing a woman's risk of developing coronary problems more than it does for a man, according to a new study.

Researchers at the University of Warwick and University College London (UCL) found that levels of "inflammatory markers" - indicators of coronary heart disease - vary significantly with the duration of sleep in women, but not men.

Previous studies have found that people who sleep less than 5 hours every night have a higher incidence of dying from heart disease, when compared to those who get the the complete 8 hours. According to the present study, the levels of a molecule called interleukin-6 (IL-6), which is known to cause inflammation, were significantly lower in women who said that they slept for at least eight hours, compared to their counterparts who reported sleeping not more than 7 hours per night. Levels of another molecule, high-sensitivity C-reactive protein (hs-CRP) - which is associated with cardiovascular problems - were significantly higher in women who reported sleeping for 5 hours or less.

The experts based their conclusions on findings from the first largest study that set to investigate the relationship between markers and sleep duration in both males and females. For the study purposes, the researchers involved more than 4,600 participants, of which 73 per cent were men. Individuals between the ages of 35 and 55 years were invited to participate in the study between 1985 and 1988. All the participants were from 20 London-based civil service departments and all the information for this study was obtained from the follow-up period between 1991 and 1993. The subjects were asked to fill out appropriate questionnaires and report about their sleep habits, and their general health was assessed during a screening examination.

A principal author of the study, Dr. Michelle Miller, an associate professor of biochemical medicine at Warwick MedicalSchool, said that the findings support the already known idea that lack of sleep is linked to a higher incidence in cardiovascular risk and that the association between sleep duration and cardiovascular risk factors is markedly different in men and women. Dr. Miller said that short-term previous studies on the matter of sleep deprivation, have demonstrated that inflammatory markers are elevated in individuals who suffer lack of sleep, suggesting that inflammatory mechanisms may play a role in the cardiovascular risk associated with sleep deprivation.

The results of the new study are also consistent with the idea that sleeping between 7 and 8 hours a night appears to be optimal for a person's health. The experts said that more studies are needed to find out why lack of sleep has a greater effect specifically on women. However, Dr. Miller said that differences in male and female hormone levels might be key. There is one research that found that inflammatory marker levels are different in pre- and post-menopausal women.

According to the British Heart Foundation, getting enough hours of sleep is important, not just for heart health but for overall well-being.

The findings are published in the American journal Sleep.