A couple of months ago, we explored some recent findings on why it’s important to get a good night’s sleep. It’s basically been shown that when we sleep, our brain performs important “housekeeping” chores. Specifically, potentially damaging chemicals are washed out of our brains while we’re asleep, chemicals linked to Alzheimer’s disease. Furthermore, sleep deprivation might increase a person’s risk of having a metabolic disorder (such as obesity and diabetes). If those aren’t enough reasons to try and catch enough z’s, then perhaps the results of some recent studies that connect sleep deprivation (and getting too much sleep) to depression will make you reconsider your bedtime tonight — particularly if you tend to remember your dreams well.
In early February, a large twin study was published that found a strong correlation between sleep duration and occurrence of depression. Specifically, compared to people who got a normal amount of sleep (7 to 8.9 hours a night), individuals who nightly had at most 5 hours of sleep, or — on the other extreme — 10 hours of sleep, were about twice as likely to report having depressive symptoms. A different study had similar results, suggesting that 6 hours or less was enough sleep deprivation to clearly increase a person’s risk of having major depression.
But in addition to the quantity of sleep, the quality is important as well, which is where dreams come in. If you usually remember your dreams when you wake up in the morning, this bit of news might be of particular interest to you.
In mid-February, a study on brain activity showed that people who do a good job of remembering their dreams actually experience periods of wakefulness while sleeping twice as frequently as people who don’t remember their dreams well. People with better dream recall were also more reactive to sounds when asleep or awake. This increased alertness might be causing the periods of wakefulness during sleep, which may, in turn, help the person better remember their dreams.
While being able to remember dreams well can be fun and fascinating, it might have negative side-effects. If a person has several periods of wakefulness during sleep, how is this affecting their overall quality of sleep (as well as total duration)? Is the brain able to efficiently do its housekeeping chores, or might disrupted sleep like this lead to a condition such as Alzheimer’s? Clearly additional research needs to be done for us to answer such questions. At least tools are being developed for people to monitor quality of sleep at home.
We’re also gaining a better understanding of how our biological, circadian rhythms are disrupted when we change our sleeping patterns. Such disruptions can be a recurrent problem for people with shift work or international travelers who frequently experience jet lag. While light and darkness are the primary cues our bodies use to sync our daily rhythms, a complex chain of molecules are involved in translating those cues into the right signals to make us go to sleep or wake up. And just last week researchers found that if they eliminate one key player (specifically CK1epsilon) in mice, the mutant mice are able to adjust their rhythms much more quickly. This understanding may eventually be used to develop a drug for people to readily adjust their rhythms, basically doing so on command. But one wonders whether this might cause other sleep-related problems — metabolic, mental, or otherwise — for a person who uses such a drug.
With all of this in mind, it may be best to try and head to bed a bit earlier instead of trying to compensate for a sleep-deprived night with a cup of coffee the next morning.
For further reading:
- Sebastian M. Schmid, Manfred Hallschmid, and Bernd Schultes’s article “The metabolic burden of sleep loss”
- ScienceDaily’s article “New links found between sleep duration, depression”
- ScienceDaily’s article “Why does the brain remember dreams?
- Violetta Pilorz et al.’s article “A novel mechanism controlling resetting speed of the circadian clock to environmental stimuli”
- Simon N. Archer et al.’s article “Mistimed sleep disrupts circadian regulation of the human transcriptome“
- Teisha J. Rowland’s Biology Bytes article “Sleep on the Brain”
- Teisha J. Rowland’s book Biology Bytes: Digestible Essays on Stem Cells and Modern Medicine