Science and Common Sense About Physical Activity –…

I discovered Dr. I-Min Lee, a professor of medicine at Harvard School of Medicine, in this video on the channel “Viva Longevity”. Among other things, she is one of two principal investigators in the famous Women’s Health Study, and is in a good position to give out science-based advice on physical activity for health. I found her to be extremely knowledgeable and also delightful!

My favorite anecdote was her discussing working with one of her mentors, the legendary Dr. Ralph Paffenbarger. He was an epidemiologist who pioneered studying the connection between physical activity and health, and also a serious ultra-marathoner. When they would attend conferences together people would ask him what his recent running achievements were, and he would quote an impressive time in a recent event. Sometimes they would turn to her and ask “and what do you do for exercise?” and she’d have to sheepishly reply “nothing”. She had grown up in Malaysia which she describes as very hot and muggy, which did not inspire her to do much physical activity.

This made her realize she’d better work activity into her own life to have her research results taken more seriously. This makes her a perfect role model for those of us who know we should be physically active for health, but are not necessarily inspired to be athletic. And her scientific knowledge allows her to show us the right amount and right types of activity to be healthy.

I was pleased to hear her confirm that typical guidelines (which her research contributed to) of trying to get 150 minutes of moderate physical activity (such as brisk walking) per week yields about 90% of the health benefits. For those who enjoy it, no harm comes from up to ten times this amount. But the benefits return increase only marginally after doing the minimum recommended amount. This can be in dedicated sessions such as 30 minutes a few times a week, or in multiple shorter sessions accumulated throughout the week. So working activity into daily life, for example using the stairs instead of the elevator, or parking a bit further away and getting some walking in, also count. Another amusing anecdote she gave is that her department at Harvard is on the third floor of her building, and Dr. Lee always takes the stairs. But many people on her floor use the elevator instead, and if it is out of service they linger in the lobby as if unsure what to do.

An important point she covered for those who like to count their steps is that there is not actually a scientific basis for the famous “10000 steps” goal. That originated from marketing for a pedometer company. From the Women’s Health Study it is confirmed that a target of 7500 steps is actually more accurate (of course there is nothing wrong with 10000 if you enjoy it, but it is not necessary to get the health benefits).

This particular video did not cover strength training for older adults, but I am sure there is plenty of insight into that from Dr. Lee’s research. There is a lot more information in the book she edited, Epidemiologic Methods in Physical Activity Studies.

Published by BionicOldGuy

I am a Mechanical Engineer born in 1953, Ph. D, Stanford, 1980. I have been active in the mechanical CAE field for decades. I also have a lifelong interest in outdoor activities and fitness. I have had both hips replaced and a heart valve replacement due to a genetic condition. This blog chronicles my adventures in staying active despite these bumps in the road.
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Published
February 20, 2025February 19, 2025