One prerequisite for a good nights sleep for adults is some healthy exercise during the day. At least that seems to be in the direction where most of the evidence is pointing. We like to make sure our children are well exercised too and we often express the sentiment after a hectic day out that “they’ll certainly sleep well tonight.”
But will they? A study by Pesonen et al on 275 8-year olds puts this old wisdom in doubt (1). They strapped accelerometers onto the wrists of their young subjects to measure activity and followed the group for a week to measure their sleep patterns.
Shock horror! Contrary to legend and their own hypothesis, lots of exercise did not improve the sleep patterns. The duration and quantity of sleep were both reduced in response to moderate or vigorous activity compared to more couch-potato days.
Why would that be they wondered, as do we all? They suggest that the body response of their youngsters to high physical activity is to increase their cortisol levels and this stress hormone could be keeping them on high alert. Surprisingly, the problem with vigorous activity was not related to the time of day, so even if it was avoided in the evening, the sleep patterns were still disrupted.
This difference between young and adult experience, perhaps, points to a different way that vigorous activity is felt. As we get older, maybe we don’t get so excited and just plow on trying to get through it and back to our armchairs, whilst our youngsters are fully mentally engaged, so their excitation level is high. Does this mean that we oldies have forgotten how to enjoy life like the youngsters?
