Exercise Boosts Body’s Virus-Fighting Proteins

Exercise boosts the activity of interferon, a natural virus-fighting substance, Italian scientists report.

Interferon, a class of proteins produced by cells that have been infected with a virus, signals nearby, but still uninfected, cells to produce an anti-viral protein, which in turn protects those uninfected cells from the virus.

It is part of the body’s natural defense mechanism.

The Italian research, reported in the Journal of Applied Physiology, found that interferon activity in eight normally sedentary men more than doubled following an hour on a stationary bicycle. The men were exercising at 70% of their maximum capacity.

It is not known whether the same effect would occur in people who exercise regularly. Nor do scientists know whether this temporary boost in interferon would make people less susceptible to viral diseases, which include colds and the flu as well as more serious diseases, such as some cancers.

Other research has shown positive immune effects of exercise. One theory, according to the Federation of American Societies for Experimental Biology, says that a muscle, thrown into trauma by exercise, acts as if it is inflamed, and the body responds to that.