Variously on this site I have reported on the health benefits of getting enough sleep (see here for a relevant article). My attention was drawn to a study published this week which assessed the relationship between sleep time and susceptibility to the common cold in a group of about 150 male and female adults [1]. In this study, the subjects were asked to record their sleep time for 14 consecutive days. After this, the individuals were quarantined, and had the common cold virus (rhinovirus) administered to them via some nasal drops. The individuals were monitored for the development of cold symptoms until 5 days after the drops were administered.
The results showed that those who slept for an average of less than 7 hours of sleep each night were about 3 times more likely to contract a full-blown cold compared to those sleeping 8 hours a night or more.
The researchers who conducted this study also assessed the relationship between ‘sleep efficiency’ (the percentage of time spent in bed during which subjects were actually asleep) and susceptibility to infection. Here again, they found a significant association: individuals with less than 92 per cent sleep efficiency were 5 and a half times more likely to develop signs of an infection compared to those with a sleep efficiency of 98 per cent or more.
The researchers looked at other factors that might explain why lower levels of sleep and lower sleep efficiency is associated with increased susceptibility to infection including antibody levels to the cold virus before administration of the virus, season and health practices. None of them explained the association, which makes the case for a real association between sleep habits and immunity a real one. On top of this, there is research which has found that inducing sleep deprivation in subjects can also induce changes that suggest weakening of the immune system.
Taken together, the research suggests that adequate sleep is important for optimal immune functioning and resistance to infection. It’s another good reason to see sleep not as a waste of time, but an important investment in our health and wellbeing.
References:
1. Cohen S, et al. Sleep habits and susceptibility to the common cold. Arch Intern Med. 2009;169(1):62-7.
I wonder what a power nap does in this context. Might one be able to do less hours of semi-coma during the night and compensate with a power nap e.g after work.
how does that fit with the premise that too much sleep can kill you, more than 8 hours in fact?
so presumably one would become a really, really virus free corpse!
Louise : Can you explain how too much sleep kills. It sounds odd to me. I regularly have 9 hours or more a night.
I would like to see a study that gave poor sleepers instructions on how to improve their sleep. Then give the poor souls a cold virus.
Would those who manage to improve their sleep be less likely to catch the cold compared to poor sleepers with no sleep advice?
However, I suspect it’s much easier to run experiments using sleep deprivation than help people sleep better.
I suffered a winter ‘bug’ in December (I am not normaly susceptible to these seasonal ‘bugs’) and the strangest thing is, I have been sleeping far more than normally ever since. Although I ‘suffer’ from sleep deprivation ie, often take hours to ‘go off’ and then wake regularly, I used to always get up quite early (from 6.30 on). However, for the last few weeks, I have been ‘sleeping in’ till gone 9am an beyond. I never completely recovered from the December ‘bug’ and I wonder if this extra sleep is a natural requirement to fight/overcome this lingering virus?
hi hilda, sorry for delayed rely, coputer problem.
there was an article regarding sleep in december:
http://www.drbriffa.com/blog/2008/12/27/getting-enough-but-not-too-much-sleep-may-be-important-for-preventing-heart-disease/
i was lightheartedly referring to this in my comment above.
perhaps you should read it if you are sleeping 9+ hours per night.
who knows what the right thing is.
please excuse typos, obviously need to get to bed…zzzzzzzz