1. Researchers say that jogging alone is unhealthy.
P. It was found that communal joggers have double the number of brain cells as solo runners.
Q. These positive effects are suppressed when running occurs in isolation.
R. Experiments indicated that running alone stifles brain cell regeneration.
S. Experienced in a group, running stimulates brain cell growth.
6. However, joggers around the world should remember that jogging is healthier than the rat race.