A friend shared a Time article: “Want to Live Longer? For Just 30 Minutes a Day, Do Anything Else But Sit”*. As usual, you can’t just rely on the title of the article in popular press. The article, like most such articles, relies on the results of only one research study and provides an optimistic snapshot of the results. In this case, it is a paper published in the American Journal of Epidemiology by Diaz and others—“Potential Effects on Mortality of Replacing Sedentary Time With Short Sedentary Bouts or Physical Activity: A National Cohort Study” (https://doi.org/10.1093/aje/kwy271). The fundamental take home of the articles is, of course, that one needs to move more. The researchers emphasize the superiority of moderate to vigorous exercise, but also suggest that there is a cumulative benefit of exercise bursts less than the 10 minutes or more recommendation. I think it is important to read the Time article thoroughly (and, ideally, the AJE article, as well) for the complete picture and to understand the distinction between exercise and physical activity. Moreover, don’t use headlines for your exercise recommendations.
Physical activity is any activity above resting levels, so anything other than sitting is physical activity, but standing is hardly a sufficient alternative. The researchers emphasize light intensity and moderate-to-vigorous physical activity (LIPA and MVPA). The data suggest that MVPA mitigates greater health benefits. LIPA might involve short breaks from sitting throughout the day to walk around a bit. (My frequent trips to the restroom would be included in this category.) MVPA would involve activities such as taking the stairs instead of the elevator. It would benefit any sedentary individual to accumulate a total of at least 30 minutes a day of LIPA to MVPA—striving toward a goal of 30+ minutes of MVPA.
Exercise is defined as physical activity that is done for the purposes of improving one’s health, performance, and/or physical appearance. Technically, intentional LIPA and MVPA may be categorized as “exercise”, but this would fall on the minimal end of the exercise continuum. While LIPA and MVPA may be performed for health benefits (such activities will have minimal to no effect on performance or body composition except for the most out-of-shape persons), they should not be considered a substitute for regular moderate-to-vigorous exercise MVE. One should still schedule time to specifically overload the health-related (cardiorespiratory, muscle endurance, muscle strength, flexibility, body composition) and motor skill-related (speed, power, agility, balance, coordination, reaction time) components of physical fitness according to one’s goals and needs. Biking to work, for example, may, as a MVPA (more like light-to-moderate physical activity, have health benefits as well as environmental benefits, but it is not a substitute for taking a spin class (MVE).
A friend recently suggested that I address the “need to strength train for lower body even if you do ‘cardio’.” I had considered a separate piece on this, but it fits in today’s topic. My friend’s frustration is with clients who say, “I don’t need to lift for my legs, I work them enough jogging on the treadmill.” I can empathize. I tell my students quite frequently that my 50-something peers who claim their noon-hoops game as “cardio” are quite wrong. This may be classified as MVPA but it will hardly have the same benefit of a focused MVE bout on a treadmill.
Exercise is specific—the body system makes specific adaptations to imposed demands. Thus, a well-balanced approach to healthy living should include a well-balanced approach to exercise. Certainly, include as much LIPA and MVPA as you can, but do not allow this to be a substitute for the progressive overload of the cardiorespiratory, musculoskeletal, and nervous systems. Include exercise!
As for those who would say, “I don’t need to lift for my legs…”? Sorry, but you do. Cardio is good for the heart, but it isn’t necessarily good for the muscle. Often, it can result in the loss of muscle mass—particularly the larger and stronger fast-twitch fibers. If one is doing cardio for fat loss, this might actually slow the progress. As well, muscle strength benefits cardio performance. Running speed is dependent upon muscle strength to drive stride length and stride frequency (what affects speed). Proper weight lifting also benefits the endurance exerciser by reducing the imbalances that can lead to injury, and strong muscle better absorbs the impact forces of running (thus, reducing injury).
My take home from the Time article is: more LIPA, more MVPA, more MVE, and less sitting. In short, move (more)!!
Be your best today; be better tomorrow.
Carpe momento!