UCLA researchers shine light on sleep management and hygiene
By Emily Tice
Sept. 20, 2009 3:18 p.m.
Jerome Siegel, professor in residence at the David Geffen School of Medicine, said he believes our society has a negatively distorted perception of sleep.
“Sleep is an adaptive state,” he said.
Siegel said that research usually focuses on the negative consequences of sleep, such as not being able to care for young or otherwise react to stimuli. But the reality is that animals are quite responsive while sleeping.
If they do not have a safe place to rest, they will sleep less, and less deeply, Siegel said.
He added that attempts have been made to correlate sleep with all sorts of qualities, one of the more popular ones being memory consolidation, but the results rarely have significance and are often conflicting. And though the brain requires a significant amount of energy, there is no correlation between sleep and brain size or intelligence, he said.
“They say Einstein used to sleep a lot,” Siegel said, “but there is no relationship between sleep and IQ.”
However, researchers have found that sleep has other correlates ““ in our ability to manage weight, for instance.
Sarosh Motivala, assistant professor in residence at the David Geffen School of Medicine, found that levels of the hormone ghrelin, which stimulates appetite, is 30 percent lower in insomnia patients at night than in healthy sleepers.
But this is counterintuitive, he said, because those who suffer from chronic sleep loss tend to gain weight over time. While the correlation between sleep and weight gain is clear, the mechanism behind it is not fully understood.
“The decrease of ghrelin in insomnia patients is similar to those with Type 2 diabetes or obesity. People who are overweight or obese actually have lower ghrelin levels, which is the opposite of what you’d expect,” Motivala said.
He said that there may be a switch that occurs during the day, in which ghrelin levels substantially increase, causing those with insomnia to eat more.
Motivala also studies how sleep affects our immune response, specifically cytokines, molecules which are vital for immune cells to communicate with one another. They elicit an inflammatory response which helps clear the virus.
However, cytokines are not only used to communicate between immune cells, but also to communicate with the brain, he said. The brain uses information from the cytokines to elicit a set of sickness behaviors, such as the perception of fatigue and social withdrawal which encourage the animal to be on its own, and it also affects sleep.
What Motivala said he finds interesting is that it works both ways: a lack of sleep increases the levels of inflammatory cytokines, which signals an immune response. Over time, they increase blood pressure and cardiovascular disease.
“You want an active immune system, but not an overly active one,” he said.
Michael Irwin, professor in residence at the David Geffen School of Medicine, said that the likelihood of acquiring a cold or other infections is also heightened by a lack of sleep because it decreases the function of T cells, which in turn make the body more susceptible to illness.
Irwin said that maintaining good sleep hygiene by setting a regular sleep schedule is very important to overall health.
People tend to underestimate the ability of exercise to help set regular schedules, and also underestimate the effect caffeine has in disturbing sleep, which, in addition to making it harder to fall asleep, also decreases the quality, he said.
“We spend most of our time inside, but we need natural lighting to help set our circadian clock,” Irwin added.
But Motivala said that, while sleep is an important biological function, it is not one we easily control.
“We can only make our environment conducive to sleep. It’s not like hunger. If you’re hungry or thirsty, you can make it go away immediately, but you don’t make yourself fall asleep,” he said.
He added that there is little utility to trying to sleep when not tired, because it can result in frustration and anxiety which ultimately makes it harder to sleep. Counting sheep or listening to relaxation tapes may be too mentally stimulating, but neutral activities, such as reading a book, may help.
Siegel said that sleeping pills are easy but not effective in the long run. Individuals who medicate themselves don’t live as long as those who refrain from it, and the best treatment for those with insomnia is behavioral therapy, which has fewer downsides.
Siegel said that studies show the optimal amount of sleep time is seven hours. Even when controlled for age, weight, gender and disease, those in studies who slept seven hours were most likely to be alive in five years. However, those who slept less than seven hours were more likely to survive the five years than those who slept more than seven.
“There’s this myth in the media that you should be very worried about losing any sleep. But the best treatment is to try to keep regular hours and go on with things and not worry that you’re shortening your life span,” he said.
However, Siegel added he is not suggesting that sleep is not important.
“Sleep deprivation degrades performance,” he said. “That’s indisputable.”
