It may be widely known that the sleep is important for physical and mental health, yet a study published in the journal Current Biology finds that a good night’s sleep it even helps our immune system to respond to vaccination.

Through meta-analysis of data, scientists found that people who slept less than six hours a night produced significantly fewer antibodies than people who slept seven hours or more. This deficit was equivalent to two months of antibody reduction.

“Good sleep not only enhances but can also prolong the duration of vaccine protection,” notes lead study author and University of Chicago professor emeritus Eve Van Cauter.

When the coronavirus pandemic broke out and mass vaccination became an international priority, Eve Van Cauter and co-lead author Karin Spiegel, from the French National Institute of Health and Medicine, scoured the literature and re-analyzed the results of seven studies on vaccines for viral infections (flu and hepatitis A and B);

The finding, however, clarifies that it applies to men, as the effect of sleep duration on antibody production was much more variable in women, and this difference is likely due to fluctuating levels of sex hormones in women, the authors say.

“We know from immunological studies that sex hormones affect the immune system. In women, immunity is affected by menstrual cycle status, contraceptive use, menopause and postmenopausal status, but unfortunately none of the studies we summarized had data on sex hormone levels,” says Karin Spiegel.

Also, the negative effect of insufficient sleep on antibody levels was greater for those aged 18-60 than for those over 65. This was not surprising, according to the researchers, because older people tend to sleep less. Going from seven hours of sleep a night to less than six isn’t as big a change as going from eight hours to less than six.