Numerous studies show that small tweaks to one's routine can improve a person's health. Some recent examples on the effect of small amounts of exercise:
Heart health: An August study in the journal Circulation found that small amounts of moderately paced leisure activity — as little as 20 minutes a day — lowered people's risk of coronary heart disease by 14%. The paper, which pooled data from 33 studies, found that higher activity levels lowered the risk more than light activity did. But even those who got less than 150 minutes of exercise a week (the minimum amount recommended by the government's 2008 Physical Activity Guidelines for Americans) had a lower risk than did those who were sedentary.
Blood flow: A 2011 study found that brisk walking a few times a week improved blood flow by as much as 15%. The research, presented at the April Experimental Biology meeting in Washington, D.C., assessed 16 women who were 60 and older. The women engaged in an exercise program tailored to their fitness levels over a period of three months, starting light — exercising for 30 minutes three times a week at about half of their maximum oxygen uptake — then gradually increasing the intensity and time of their workouts. Blood flow to the brain increased an average of 15% in the women's left internal carotid artery and 11% in their right internal carotid artery (the arteries are in the neck and supply the brain with blood). The women's blood pressure and heart rates decreased slightly.