Another reason to feel guilty for not working out
We have long known that the young (both people and mice) tend to be more active than the elderly. And furthermore, that the older one gets (whether one is a mouse or a person), the more random one's activity patterns tend to be. Your overall activity level goes down, and you are more likely to be active at random, inconvenient times. Older people may find themselves restless in the middle of the night, and tired in the middle of the day.
Now comes a new study which sheds light on this mystery of biorhythms: it's all about exercise.
Researchers took two groups of mice. One group of mice had access to an exercise wheel, and the other did not. The mice with easy exercise access were more active when they were younger, both on and off the wheel, and their activity patterns were more regular. They would be active for a while, then rest.
The other group had an overall lower activity level, even adjusting for time spent on the wheel. As they aged, their activity levels dropped proportionately even lower than that of the group with the exercise wheel.
Interestingly, the activity patterns of the non-exercising mice also were significantly more random than the mice that exercised. The non-exercising mice would be awake when they should be asleep, and asleep when they should be awake. The researchers theorize that regular exercise helps regulate our overall activity and sleep cycles, although the specific mechanism is not clear.