Lack of Sleep May Lead to More Colds

Research in recent years has led to a general consensus that at least 7 hours sleep a night are desirable for good health; more than 8 hours, however, carries a greater risk of various health problems. In this connection, a study published in the Archives of Internal Medicine in January examined the relationship between sleep habits and susceptibility to the common cold.

A total of 153 healthy volunteers, men and women aged 21 to 55, were recruited. They recorded details about their sleep each night for 2 weeks, and then they were quarantined and given nasal drops containing a rhinovirus (the cause of the common cold). The presence (or absence) of a cold was recorded on the next 5 days.

The likelihood of developing a cold was associated with the average duration of sleep. Thus those subjects who slept less than 7 hours a night were 3 times as likely - actually 2.94 times – more likely to develop a cold than those who slept 8 hours or more.

The effectiveness of sleep (the percentage of time in bed actually asleep) was also a factor. Participants who claimed less than 92% effectiveness were more than 5 times as likely to develop a cold as those with 98% or better effectiveness.

The report concludes: “Poorer sleep efficiency and shorter sleep duration in the weeks preceding exposure to a rhinovirus were associated with lower resistance to illness”. Note that you still need a rhinovirus exposure to develop a cold – in other words, lack of sleep can lower your susceptibility, but doesn’t ‘cause’ a cold infection. It would be interesting to know if the resistance to other viral infections is influenced by lack of sleep. But don’t lose any sleep worrying about it . . .