How do weighted blankets boost sleep?

A new study shows that using a weighted blanket at bedtime increases melatonin in young adults. This hormone increases in response to darkness, and some evidence suggests that it promotes sleep. While previous research has shown that weighted blankets may ease insomnia, the underlying mechanisms are not fully understood.

Researchers recruited 26 young men and women to examine if the bedtime use of a weighted blanket increases the production of sleep-promoting and anti-stress hormones like melatonin and oxytocin. In addition, they investigated whether the bedtime use of a weighted blanket (12 percent of participants’ body weight) reduced the activity of stress systems in the body.

Saliva was collected repeatedly from participants while they were covered with either a weighted or a light blanket to measure melatonin, oxytocin, cortisol, and the activity of the fight and flight sympathetic nervous system. The findings are published in the Journal of Sleep Research by a research team based at Uppsala University, Sweden.

‘Using a weighted blanket increased melatonin concentrations in saliva by about 30 percent. However, no differences in oxytocin, cortisol, and the activity of the sympathetic nervous system were observed between the weighted and light blanket conditions,’ says Elisa Meth, Department of Pharmaceutical Biosciences at Uppsala University.

The study may help to explain the mechanism behind the apparent benefits of weighted blankets. However, the sample size is relatively small for a sleep study. ‘Our findings rely on a small sample and investigated only the acute effects of a weighted blanket,’ says Christian Benedict, Associate Professor of Pharmacology at the Department of Pharmaceutical Biosciences at Uppsala University. ‘Thus, larger trials are needed, including an investigation of whether the observed effects of a weighted blanket on melatonin are sustained over longer periods.’