1999-Chalk up another benefit for regular exercise. But we now have evidence for it, and it appears that exercise helps this happen. The investigators began their study by comparing the memory skills of a group of sedentary mice to those of a group of mice who exercised freely on a running wheel for one month. Mice in the exercise group logged an average daily distance of 4.87 kilometers, or 2.92 miles. Both groups were trained to locate a submerged camouflaged platform in a maze that was lying just below the surface in cloudy water.
Mice dislike swimming and instinctively seek the platform as a refuge from the stressful activity.
After six days of training each group of mice for the swimming task, the researchers began the study. The group of mice that had been exercising made a beeline for the platform. In contrast, the sedentary mice took significantly longer paths and times to find the dock. Based on the swimming test, mice in the exercise group were better able to remember the platform's location compared to mice in the sedentary group. Next the researchers looked for changes in the number of nerve cells between the two groups of animals.