In theory, you could also cram all of your workouts into long Saturday and Sunday workouts. In a 2017 study by Dr. Stamatakis and colleagues, people who said they exercised almost entirely on weekends were less likely to die prematurely than those who said they rarely exercised . But being a weekend warrior has its downsides. “It’s certainly not ideal to spend the work week completely sedentary and then try to compensate” over the weekend, Dr. Stamatakis said. You miss out on many of the health benefits of regular exercise, such as better blood sugar control and improved mood, on days you don’t exercise, he said. You also increase your risk of exercise-related injuries.
Count your steps.
Exercise recommendations remain the same if you measure your exercise in steps instead of minutes. For most people, “150 minutes of exercise per week would translate to about 7,000 to 8,000 steps per day,” Dr. Lee said. In a new large-scale study by Dr. Lee and Dr. Ekelund on the relationship between steps and longevity, published in March in The Lancet, the optimal number of steps for people under 60 was around 8,000 to 10,000 a day, and for those 60 and over it was around 6,000 to 8,000 a day.
Of course, these steps and minutes recommendations focus on health and lifespan, not physical performance. “If you want to run a marathon or a 10k race as fast as possible, you need a lot more exercise,” Dr. Ekelund said.
The recommended 150 minutes per week may also be too little to avoid weight gain as you age. In a 2010 study of nearly 35,000 women led by Dr. Lee, only those who walked or exercised moderately for about an hour a day in middle age maintained their weight as they aged.
So if you have the time and inclination, move for more than 30 minutes a day, said Dr. Lee and the other scientists. In general, according to his research and other studies, the more active we are, well beyond 30 minutes a day, the lower our risk of chronic disease and the longer our life can be.
But any activity is better than nothing. “Every minute counts,” Dr. Ekelund said. “Climbing stairs has health benefits, even if it only lasts a minute or two, if you repeat it regularly.”
Gretchen Reynolds will be taking time off from PhysEd to work on a book. In the meantime, follow her on Twitter (@gretchenreynold) or look for it on running trails and bike paths.