Short periods of deep sleep and dream sleep are also contribute to an increased risk of obesity, according to the study carried out at Uppsala University, the results of which are published in the May edition of the scientific journal Sleep.
“This correlation between a short sleep span and obesity was particularly strong among younger women,” Jenny Theorell-Haglöw, the author of the study, told local newspaper Upsala Nya Tidning.
The study compared women who get at least eight hours sleep a night with those who sleep less. Some 400 women participated in a night-long sleep test, while also undergoing a health examination and agreeing to have the circumference of their waists measured. The study registered the duration of sleep and the length of various stages of sleep.
The waist circumference of women who slept less the five hours a night was found to be nine centimetres longer on average than for their counterparts who slept eight hours a night.
Theorell-Haglöw said there were a number of possible explanations for the connection between obesity and sleep.
“Short sleep duration, short dream sleep and short deep sleep disturb the production of cortisol and growth hormones in a way that can contribute to driving body weight upwards. Sleeping less also means more waking time when it’s possible to eat,” she said.
The results from Uppsala tallied with earlier studies seeming to suggest that lack of sleep could be a contributory factor to growing societal problems with obesity.
“But further research is needed to answer the question as to whether there is a causal relationship,” said Theorell-Haglöw.