Sleep Walking, Sleep Talking... Sleep Emailing?!?

If you thought sending your boss an email after a couple of beers was a bad idea, how about doing so whilst you're asleep?

Up until now it was thought that the possible range of activities when asleep was limited to fairly crude motor functions such as sleepwalking or mumbling incomprehensibly. Now the New York Times reports on what's believed to be the first documented case of "complex nonviolent cognitive behaviour": sleep emailing.

A woman who was staying at a relative's house managed, whilst asleep, to turn on the computer, log in to the email system and send an email. To be precise she emailed a friend saying "come TOMORROW AND SORT THIS HELL HOLE Out!!!!!!". Ouch.

The case, which is due to be published in the journal Sleep Medicine, is unusual. The woman was already undergoing treatment for severe insomnia and had recently increased her dose of zolpidem (Ambien) above that prescribed by her doctor.

So sending abusive or lustful emails in our sleep is probably not something most of us need worry about too much. But it is possible.

Sleep and the Common Cold

New research has found evidence for what many people have long believed: getting good night's sleep is related to your resistance to the common cold. The study, Sleep Habits and Susceptibility to the Common Cold was published in the Archives of Internal Medicine.

Researchers studied 153 volunteers and measured how long they slept (sleep duration) and how rested they felt (sleep efficiency). After 14 days the participants were then exposed to the human rhinovirus that causes the common cold. Those who slept less than seven hours a night were almost three times as likely to catch a cold as those who slept eight hours or more. Those with a lower level of sleep efficiency were also significantly more likely to catch the cold.

The researchers concluded:

"Poorer sleep efficiency and shorter sleep duration in the weeks preceding exposure to a rhinovirus were associated with lower resistance to illness"

As always, correlation does not necessarily mean causality.

Sleep and Cholesterol

New research suggests a link between sleep patterns and cholesterol levels in the elderly. The study, Long Sleep Duration is Associated With Serum Cholesterol in the Elderly: The Rotterdam Study, was published in the journal Psychosomatic Medicine.

The research team studied 768 participants aged between 57 and 97, none of whom used cholesterol lowering drugs. They found definite links between sleep patterns and raised cholesterol levels.

There seemed to be two different factors associated with the increase in cholesterol: in subjects aged below 65 the main link was with increased total time in bed, with those aged over 70 the main link was with sleep fragmentation. The researchers concluded:

"A longer sleep duration was related to higher total cholesterol level and a higher total/HDL cholesterol ratio. Two separate mechanisms, a longer time in bed and sleep fragmentation, seem to explain these associations in different age categories."

It's important to remember that correlation doesn't necessarily mean causality. There may be other factors such as physical fitness and activity levels that affect both sleep patterns and cholesterol levels.