Running seriously low on sleep? A nap can not only make you feel better, but can reverse the effects of poor sleep by restoring hormones and proteins involved in stress and immune health.
The fact that poor sleep can increase stress levels and suppress immune system activity is well-established. But according to a new small study, napping can be an effective antidote by creating measurable hormone changes.
Researchers from the Sorbonne University in Paris found that a brief nap was effective in relieving stress and strengthening immune system function in men who had only slept two hours the night before.
"Our data suggests a 30-minute nap can reverse the hormonal impact of a night of poor sleep," study co-author Dr. Brice Faraut said in a statement. "This is the first study that found napping could restore biomarkers of neuroendocrine and immune health to normal levels."
The researchers conducted sleep tests on 11 healthy men between the ages of 25 and 32. In a laboratory setting with controlled lighting and meals, the participants took part in two sessions of sleep testing. In the first session, the men were only allowed to sleep for two hours in one night. In the second session, the men were allowed to take two 30-minute naps the day following a night that they got only two hours of sleep. On the evening prior to both sessions, the subjects got eight hours of sleep.
Then, the researchers took samples of the mens' urine and saliva to test how the lack of sleep affected their hormone levels. After the night of only two hours of sleep, the mens' levels of norepinephrine -- a stress hormone and neurotransmitter involved in the fight-or-flight response, which increases heart rate, blood pressure and blood sugar -- was two and a half times higher than they were after a normal night of sleep. After a night of sleeping only two hours, the participants also exhibited a dip in interleukin-6 levels, an antiviral protein that stimulates immune response to infection or in the aftermath of trauma.
However, when the men had napped twice after a night of limited sleep, the researchers found no change in norepinephrine levels. Interleukin-6 levels also returned to normal after napping.
The findings suggest that napping can reverse the some of the negative health effects of poor sleep and can also promote overall well-being.
"Napping may offer a way to counter the damaging effects of sleep restriction by helping the immune and neuroendocrine systems to recover," Faraut explained. "The findings support the development of practical strategies for addressing chronically sleep-deprived populations, such as night and shift workers."
If that wasn't reason to get a little midday shut-eye, napping has also been shown to boost mood, productivity and creativity, and to facilitate learning and memory. A 2011 study also found that those who napped for at least 45 minutes had lower blood pressure in response to psychological stress than those who did not nap.
The findings were published in the Journal of Clinical Endocrinology & Metabolism (JCEM).