Is sleepiness related to cheerfulness?

25 April 2013


I'm wondering about the fact that I and two of my sons are consistently able to wake up quickly, in a happy demeanor, whereas my wife and other son (a) have trouble waking up - no matter how much sleep they've had, and (b) have a somewhat less cheerful disposition. Could this be genetically based?


Hannah - Is there a relationship between being an early riser and being chipper? We turn to the sleep clock expert, Dr. Mick Hastings from the Medical Research Council in Cambridge. He had some follow up questions for Stuart and it turns out that grumpy family members are still grumpy even if they get to have lines and adjust their sleeping patterns during long holidays. So, it doesn't seem to be the case that the bad mood was simply due to going against their midnight owl body clock cycles. So, given it's not natural body clock differences, what could be going on in the brains of these different groups? Michael - Well, this is where it gets more biochemical, but I'd argue even more interesting. We do know that how well we feel, our mood, of course, is determined by the chemicals in our brain, the neurotransmitters which are active. And we also know that the body clock controls the activity levels of those neurotransmitters. There's one in particularly called serotonin which is also called 5HT which is a sort of happy neurotransmitter and quite a number of drugs which are used to control people's moods act through serotonin and the receptors it works upon in the brain. So, one possibility could be, there's just something different in the way in which the body clock controls serotonin patterns in the grumpy and happy people within this family. Something else we could look at where we know the body clock has a direct effect on mood is through a hormone called cortisol. Now cortisol is very important because it energizes the body, sends sugars into the bloodstream, increases heart rate, muscle tone, and what have you. So, it's the hormone that's secreted under the control of the body clock, just before we wake up. Which is great, you jump out of bed, you're ready to go. Perhaps there's something different in the cortisol patterns. We know they do vary enormously between people because an important feature of cortisol is that not only does it energize the body. It does have a suppressive effect on mood. Now, of course I'm not a clinician, I'm a basic biologist, but an interesting experiment would be to take some saliva samples from individuals, measure their cortisol levels and just see if there's a correlation or relationship between how grumpy people are in the morning and their morning levels of cortisol. Hannah - So, possibly changes in the serotonin or cortisol levels in the brain could be affecting these morning moods. In this case, is there anything that Stuart's wife and grumpy son can do to cheer themselves up in the morning? Michael - I think it's important to think about what might make them happy. Perhaps they could give themselves some little treats to wake up to. You know, a hot cup of drinking chocolate or the sunlight shining on the bedroom wall.

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