A couple of new reports came out this week addressing sleep in our culture. Everyone knows that they feel a little cranky when they don't get enough sleep. It's therefore no surprise that sleep affects your mood. What may be surprising, though, is that scientists know very little about why that's true.



We understand quite a bit about why sleep disrupts your immune function, your metabolism and your ability to learn and remember things. I have discussed each of these in past articles. But we don't know much about how sleep regulates mood. An interesting new study published in Current Biology by Michael Walker, sheds some light on this subject.

A loss of reason

A complex brain circuit that involves both higher thinking centers and reactive centers controls your emotions. It's the higher thinking centers that separate us from other animals. We have the ability (although we don't always use it) to evaluate our responses thoughtfully, before just reacting impulsively.

In the new study, volunteers were either deprived of a good night's sleep or allowed to sleep normally. Researchers then looked at both their higher thinking and their reactive brain centers after presenting them with some emotionally negative images to stir their reactions.

They found that specific reactive centers of the brain acted the same whether or not the volunteers had slept well the night before. But certain higher thinking centers responsible for keeping those reaction centers under control, were much less active in the sleep deprived group.

The interpretation of this is that our ‘gut reactions' are not really that affected by lack of sleep (at least in this situation) but our ability to reason and monitor those reactions is weakened, which can have all kinds of downstream consequences.

Is a longer workday productive?

Why is this important? Other studies show that we are getting far less sleep today than we did a century ago and throughout history. The advent of artificial light has extended the length of our daily ‘productivity', but many argue that this is actually counter-productive. By not getting optimal sleep, we are decreasing our ability to function efficiently the next day, and actually getting less done.

In fact, another study just released shows exactly that. In this one, researchers, Patricia Murphy and Scott Campbell, showed that napping is actually productive. First of all, midday napping did not cause people to sleep less well at night, as many believe. Second, midday napping improved performance on math, decision-making and reaction-time tests. This increased performance was true after the nap and lasted all the way into the next day, following the nap.

Many of us are so busy that we steal hours from our sleep to attempt to get more done. But science argues that we are not getting more done this way. We are actually reducing our ability to be creative, make decisions, work efficiently and cooperate with other people. Perhaps a little more time invested in our rest could dramatically improve our career and personal relationships.

Copyright (c) 2007 BrainFit For Life