Columnist: A recent research report suggests that by exercising vigorously, one significantly lowers one' s chances of developing certain cardiorespiratory illnesses  But exercise has this effect, the report concludes, only if the exercise is vigorous
Thus, one should not heed older studies purporting to show that nonstrenuous walking yields the same benefits
fails to consider the possibility that the risk of developing certain cardio-respiratory illnesses can be reduced by means other than exercise