How Much Exercise do We need to Counter All Our Sitting?

HOW MUCH EXERCISE DO WE NEED TO COUNTER ALL OUR SITTING?

I just received the February issue of my online Harvard Health Letter. Right off, I spotted an article spelling out the dangers of sitting all day. I, like most seniors, sit way too much—at my computer, reading, or watching shows on Apple-TV or Hulu. I’ve previously sent several posts addressing our highly sedentary lifestyle and its associated health risks: What to Do After Sitting All Day? Stretch! (March 2021); Sitting All Day May Increase Your Risk of Dementia (January 2024); Kick Your Pain from Prolonged Sitting (October 2024).

 This latest article also explores why our physical activity levels have declined compared to the past. Below are key takeaways from the February 1, 2025, article by Anthony L. Komaroff, MD, Editor-in-Chief of the Harvard Health Letter, titled Does Exercise Offset the Risks of Sitting?

Is 150 Minutes of Physical Activity per Week Enough?

Doing moderate-to-vigorous physical activity (for example, walking briskly at about 3 mph) for at least 150 minutes per week [or only 22 minutes per day] improves your health. But 150 minutes per week is just 2% to 3% of the time that you’re awake. Is it really okay to be a couch potato for 97% to 98% of the time? A new international study led by a Harvard team, published online Nov. 11, 2024, by the Journal of the American College of Cardiology, followed nearly 90,000 people (average age 62), for about a decade. A careful record was kept of their past diseases, the development of new diseases, and factors that influenced their risk of major diseases (like diet, weight, use of tobacco or alcohol, etc.). For one week, a small sensor strapped to their wrists measured the time that they were asleep, sedentary, engaging in light activity, or engaging in moderate-to-vigorous activity.

The study confirmed again that moderate-to-vigorous physical activity for at least 150 minutes per week improves your health, particularly your heart health. But the study also was able to show that, among those people who got the recommended amount of moderate-to-vigorous physical activity, those who were the most sedentary the rest of the time had a greater risk of developing heart failure and dying from heart disease, when compared to those who were less sedentary.

Americans are Much Less Active than their Ancestors

Why does regular physical activity protect our health? There are two ways of asking that question: why should it, and how does it? Let’s start with “why should it?” Humans have been around for 200,000 years. In 1700, about 80% of the people in the United States were farmers; by 1900 it was down to about 40%; today it’s less than 2%. In other words, at least in the developed nations, people are not as physically active as humans have been for almost all the time our species has existed. It sort of stands to reason that such an abrupt change in something so fundamental as physical exertion might be detrimental.

As to “how does it?”: in just the past 20 years, scientists (including here at Harvard) have been discovering health-promoting molecules that are produced by our bodies when we exercise. The discoveries so far probably only scratch the surface. And none yet have led to an exercise pill. I get my “required” amount of moderate-to-vigorous physical activity each week. But after reading this study, I’ve decided to get up every hour and climb the stairs. I think being active throughout the day will improve my health.