New research by scientists from Princeton University says that running or exercising alone may not provide the benefits of exercising. The reserachers led by Elizabeth Gould at Princeton University say in Nature Neuroscience that running alone does not seem to generate new brain cells, which are found in abundance after running or exercising in pairs or in groups. The reserachers conducted a study on lab rats in order to arrive at this conclusion.
The researchers first allowed the rats to run around wheels normally and then separated some rats and put them in cages where they could exercise alone. It was found that solitary rats had increased levels of stress hormone corticosterone, which reduced the creation of new brain cells. The hormone is raised after any stressful activity like running, but in very high levels causes brain cell generation to stop. These findings seem to suggest that social contact is necessary even in beneficial activities; else they might actually harm the body. "In the absence of social interaction, a normally beneficial experience can exert a potentially deleterious influence on the brain," Dr Gould said.