Researchers registered 28 deaths among joggers and 128 among sedentary non-joggers. In general, the joggers were younger, had lower blood pressure and body mass index, and had a lower prevalence of smoking and diabetes.
“It is important to emphasize that the pace of the slow joggers corresponds to vigorous exercise and strenuous jogging corresponds to very vigorous exercise,” Dr. Peter Schnohr of Frederiksberg Hospital in Copenhagen said in an announcement of the work. “When performed for decades, this (high) activity level could pose health risks, especially to the cardiovascular system.”
The researchers, part of the long-term Copenhagen City Heart Study, say this builds on past studies showing that strenuous exercise can do more harm than good.
“The U-shaped association (i.e. on a graph) between jogging and mortality suggests there may be an upper limit for exercise dosing that is optimal for health benefits,” Schnohr said. “If your goal is to decrease risk of death and improve life expectancy, jogging a few times a week at a moderate pace is a good strategy. Anything more is not just unnecessary, it may be harmful.”