How much exercise is enough?

Exercise has a variety of benefits which have been much explored in the scientific literature. A resounding question, however, is "How much exercise is enough?". This question is especially important for individuals with hypertension (i.e., those with high blood pressure), as exercise has been shown to have profound effects on cardiovascular health.

In a study by Takata et al., 207 participants with high blood pressure were divided into 5 groups of different exercise levels: sedentary, 30-60min/wk, 61-90min/wk, 91-120min/wk, and >121min/wk. As expected, the sedentary group showed no improvements in blood pressure levels, whereas every other group did show decreases in blood pressure. The 61-90min/wk group had greater improvements than the 30-60min/wk group, but anything beyond 90min did not have a significant impact.

These results support several claims: 1) Exercise is important to cardiovascular health 2) Even fairly small amounts of exercise can show significant improvement in blood pressure 3) There is an unofficial "limit" to exercise after which blood pressure effects are not as significant. Although these notions are still supported, it should be noted that the time durations were chosen by the researchers and do not necessarily represent how much the average individual should exercise.


Source:

1.

Ishikawa-Takata K, Ohta T, Tanaka H. How much exercise is required to reduce blood pressure in essential hypertensives: a dose–response study. American Journal of Hypertension. 2003 Aug;16(8):629–33.