Feeling Hazy? New Study Says Get Back to Your Workout
Active mice deprived of exercise show cognitive decline -- and slow brain growth
If you’ve ever taken a few days off from working out only to feel hazy and anxious, you’ll be interested in the findings from a group of Japanese and Spanish researchers.
When the scientists took away running wheels from mice that exercised regularly, the animals became anxious and stopped growing as many new cells in the part of the brain responsible for memory and spatial navigation. The findings of the study were published in the journal Behavioral Brain Research.
For the study, the researchers allowed a group of young mice to use a running wheel through their early adulthood at about 12 weeks. They then put some of the mice in cages without wheels for nine weeks. At the end of this session, researchers performed behavioral tests on both groups, as well as on mice that had never had access to a running wheel.
The running mice that were deprived of wheels showed more signs of anxiety than other mice—even those who had been sedentary their whole lives.
The researchers also measured changes in brain cell growth by injecting mice with a chemical two weeks before the mice were killed. While mice who continued to run grew significantly more new brain cells in the hippocampus, the mice whose routine was interrupted experienced a massive shift in cell development. The decline didn’t just bring them back to the normal level (as measured by the always-sedentary mice), their cell development actually became the slowest of any of the mice groups.
The researchers concluded that a reduction in physical activity could be a risk factor for impaired hippocampal function.
Takeshi Nishijima, the lead researcher, believes the findings can apply to humans because many situations can lead to decreased activity, such as jobs, disease or retirement from sports.