How Much Exercise Is Enough?
March 9, 2021 in
Getting Active, Research by
Robert Ziltzer MD FACP
One barrier to exercise is the belief that you have to break a sweat for 30-60 minutes to gain any benefit. This couldn’t be further from the truth. In fact, just a small amount of exercise improves health. If that’s the case, then how much exercise is enough?
The Science Behind Exercise Benefits
In her book, “The First 20 Minutes,” NY Times science writer Gretchen Reynolds reviews the latest in exercise science. She discusses a study on heart fitness and the dose-effect of varying amounts of exercise.
In the chart below, the control group that did no exercise had a drop in heart health, as measured by “VO2.” This number measures how much oxygen the body can use during exercise. More is better, and a drop from baseline is very bad. So the control group actually lost its ability to use oxygen, and why their VO2 is below the baseline.
The group that did only 10 minutes of modest exercise gained a significant fitness level. In this test, they only took a brisk walk. Walking 20 minutes was better than 10 minutes, and 30 minutes was even better.
The greatest change occurred when increasing exercise from zero to 10 minutes.Just a bit of exercise makes a big difference. While more is better, you can feel comfortable in the knowledge that it doesn’t take much to improve health. Start small, 10 minutes a day, to develop good habits.