Let’s dig into the results of the National Health Interview Survey analysis to see if less really can be more: does mortality decrease even with fewer than 30 minutes per day most days of the week as long as part of the workouts was vigorous? We’re not examining other potential health benefits of exercise such as the risk of type 2 diabetes, weight loss, or gaining strength—just risk of death.

I examined the Hazard Ratios for the number of minutes spent in vigorous physical exercise per week and the total minutes of exercise per week. For those who exercised 1 to 149 minutes per week (less than the national recommendations), if 1 to 74 minutes of the total were spent in vigorous exercise, there was a 29% decrease in all-cause mortality. For CVD, there was a 20% decrease in mortality and a 24% decrease in mortality from cancer. There were additional benefits when a greater number of minutes were spent in vigorous activity, especially from CVD. Clearly, less can be more.

But…

A person must be fit enough to be able to do vigorous exercise. The survey defined vigorous exercise as hard enough to raise the heartrate and breathing rate and to increase sweating. The older you are, the less you may be able to sustain that type of effort, whether due to a lack of fitness or pre-existing CVD or orthopedic issues; the same holds true for someone who is overweight or obese. If you’re in any of those categories, you must get your physician’s approval before doing intense exercise.

You don’t have to wait, though; work up to it over a period of months with the guidance of a professional exercise specialist. Just as with any goal, you approach it in a stepwise manner. If you can walk for exercise, it may be something as simple as walking fast for 15 seconds every 3 minutes. Progress from there, increasing the fast walking by 15 seconds every week or every few days. If your body isn’t ready yet, it will let you know.

If you can get 20 to 30 minutes most days with over half of those minutes being vigorous, you may reap the benefit of lower risk of death, according to the data. Just proceed with caution and remember, this doesn’t include time working on strength, endurance, or flexibility.

What are you prepared to do today?

        Dr. Chet

References: JAMA Int Med. doi:10.1001/jamainternmed.2020.6331