I have alluded to the concept before, but a former student asked me recently about exercise “snacking”. I had never heard the phrase before. He was referring to the recent adjustment to the exercise guidelines by the American College of Sports Medicine (ACSM) to allow for the accumulation of multiple short bouts of physical activity for cardiorespiratory health.
Specifically, the current Physical Activity Guidelines for Americans1 reads:
“Adults should move more and sit less throughout the day. Some physical activity is better than none. Adults who sit less and do any amount of moderate-to-vigorous physical activity gain some health benefits.
For substantial health benefits, adults should do at least 150 minutes (2 hours and 30 minutes) to 300 minutes (5 hours) a week of moderate-intensity, or 75 minutes (1 hour and 15 minutes) to 150 minutes (2 hours and 30 minutes) a week of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate- and vigorous-intensity aerobic activity. Preferably, aerobic activity should be spread throughout the week.
Additional health benefits are gained by engaging in physical activity beyond the equivalent of 300 minutes (5 hours) of moderate-intensity physical activity a week.
Adults should also do muscle-strengthening activities of moderate or greater intensity and that involve all major muscle groups on 2 or more days a week, as these activities provide additional health benefits”(p. 8).
It is also suggested that “even 5 minutes of physical activity has real health benefits” (p. 11).
One very important thing to understand from these recommendations are that they are for cardiorespiratory health not performance. As such, one is not going to significantly increase one’s VO2max by simply taking the stairs or walking more (unless, of course, one is extremely sedentary and has poor cardiorespiratory fitness). More activity, however, will benefit overall health.
This being said, the question remains whether one can improve performance with exercise snacking. I would conclude that one can, although with less than optimal results. I would not, however, go as far as to recommend frequent bouts of less than 10 minutes unless the goals are highly specific—I am thinking something like the Bulgarian weightlifting program where lifters performed specific lifts in 2-3 or more daily sessions 6 times a week. Few of us could possibly lift as such, but the benefits for strength are great should one have the flexibility in their schedule. Consider how your focus and motivation wanes knowing that you have numerous exercises to perform in a single 1- to 2-hour exercise session. One is usually more inclined to “save” a little for subsequent exercises. This works great, if one is a power athlete or training for Olympic lifting. For more general fitness or athletics that require multiple dimensions of performance, such “snacking” is likely to be ill-advised.
Snacking is ideal for general health-related fitness. A number of 10-minute workouts scattered through the day are better than nothing. Among the guidelines, however, “snacking”—i.e., accumulating physical activity in bouts of less than 10 minutes is specific to cardiorespiratory endurance and muscle endurance health-related physical fitness. It is not applicable, per se, to muscle strength. In other words, taking the stairs, walking more, and dropping down for a set of ARAP pushups throughout the day will benefit you, but not as much as longer planned system-specific exercise sessions.
I am increasingly inclined to recommend strength-specific training for the aging adult exerciser as a top priority. Two to three (or more) sessions per week per body part is warranted. Secondary would be some higher volume/lower intensity work for muscle endurance and body composition (as well as a mobility work) in the form of some form of HIIRT exercise 2-3 days per week. If possible, 2-3 sessions of cardiorespiratory-specific exercise should be included. These cardio-specific sessions need not be long, but should be longer than 10 minutes. Ideally, I would recommend 20-30 minutes of HIIT. Cardio “snacking”, as such, is added benefit. The more £10-minute “snacks” we can include throughout the day the better. Look, just because you do 30 minutes on the elliptical, that doesn’t give you permission to sit on you butt all day. Move! Move often. Such “snacking” will also serve to aid in active recovery for the intensive weight training you are doing. Movement has cumulative health benefits. So, move as often as possible.
Be your best today; be better tomorrow.
Carpe momento!
1 Office of Disease Prevention and Health Promotion. Physical Activity Guidelines for Americans (2nd Ed). https://health.gov/paguidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf