Posted on 17/03/2017
Sleep varies according to gender and age
World Sleep Day, is an annual celebration of sleep and a call to action on important sleep issues - this year focussing on the call to 'Sleep Soundly, Nurture Life'.
Over twenty years ago, Professor Daniel Hamermesh of Royal Holloway's Department of Economics published research, Sleep and the Allocation of Time which examined how sleep patterns across different groups are affected by their work.
As an issue that is still very much awake, we asked Professor Hamermesh about what this work means now for rest, relaxtion and work.
Does working more have to mean sleeping less?
Research on the economics of sleep shows that the amount we sleep is not only biological—it responds to the incentives we face in work and at home. Those who can earn more—whose time in the labour market is more valuable—sleep less. For example, among British men calculations show that men in the upper quarter of households ranked by household income sleep over 30 minutes less per night than men with the same demographic characteristics but who are in the lowest quarter of incomes (and over ten minutes less per night than men in the middle two quarters).
As a headline about my research in the New York Times put it, “Sleep—why? There’s No Money in It”.
Are women affected by this labour-sleep effect?
The differences are smaller among women, roughly 20 minutes per night less than women in the lowest income quarter (and about 5 minutes less than women in the middle quarters.)
Having a child under age six in the household reduces women’s sleep time by about 15 minutes per night, but has no effect on the father’s sleep time (a gender difference that is not surprising!).
Do we sleep better in twos?
Married men and women each sleep about four minutes more per night than unmarried people with the same demographics, income, etc. (With sexual activity every five nights, and about 20 minutes per activity, this sleep difference might be fully explained by the possibility that marrieds’ reported sleep included sexual activity!) Time spent sleeping drops from early adulthood up to about age 60, then starts rising again.
What's the length of an average night's sleep?
There is a wide range of sleep time in the British population. While the average adult male reports sleeping a little over eight hours per night, ten percent of men sleep fewer than 6 hours 20 minutes, while another ten percent sleep more than 10-12 hours1 The range is about the same among British women, although the average woman sleeps a few minutes longer than the average man.
Read more about research in the Department of Economics, or hear what students have to say about studying ecomonics at Royal Holloway.