Researchers from Johns Hopkins Medicine and the Dana Farber Cancer Institute in Boston have shown that a hormone secreted into the blood during endurance, or aerobic, exercise reduces levels of a protein linked to Parkinson's disease and halts movement problems in mice.

Parkinson's disease, a neurologic condition that causes people to lose control over their muscles and movements, affects about 1 million people in the U.S.

If confirmed in additional laboratory research and clinical trials, the researchers' study in mice engineered to have Parkinson's disease symptoms could pave the way for a Parkinson's disease therapy based on the hormone irisin.