Walking and running involve the same muscle groups and the same motions, but are performed at different “intensities” – where intensity is defined in terms of “metabolic equivalents,” or METs. Exercise is considered to be of a moderate intensity if it uses 3 to 6 times the oxygen needed to sit at rest, usually defined as 3.5 ml of oxygen per kg of body weight per minute; that is defined as 1 MET. On that scale, walking is moderate intensity exercise and running, which uses more than 6 METs, is considered to be vigorous. Paul T. Williams, from Lawrence Berkeley National Laboratory (California, USA), and colleagues studied data compiled from 33,060 subjects enrolled in the National Runners’ Health Study II and 15,945 participants in the National Walkers’ Health Study. The team found that while spending the same amount of energy yielded similar reductions in the risks of high blood pressure, high cholesterol, diabetes, and coronary heart disease, runners were found to expend about twice as much energy as walkers and therefore reap greater health benefits. The study authors conclude that: “Equivalent energy expenditures by moderate (walking) and vigorous (running) exercise produced similar risk reductions for hypertension, hypercholesterolemia, diabetes mellitus, and possibly [coronary heart disease].”
