For decades, the American and the Canadian physical activity guidelines have suggested that a minimum of 10-minute duration of moderate-to-vigorous activity is necessary to provide the health benefits of exercise.
That does not match public health recommendations such as taking the stairs instead of the elevator and parking farther from your destination. Those don’t take 10 minutes, so why were they recommended?”
Due to lack of evidence, some are questioning the minimum bout of 10 minutes of activity promoted.
In fact, the recent studies are showing all physical activities are accumulated in bouts to total minutes regardless if they are one minute, ten minutes or one hour long. Regular short bouts of activity lasting only few minutes have been shown to be of benefit in weight reduction and improving BMI.
A 2017study (Allison et al) demonstrated that just three sets of 20-second duration of intense stair climbing improves cardiorespiratory fitness in previously untrained individuals.
So does the activity have to be moderate or vigorous? Not always! A 2018 study (Dhorn et al) that followed seniors for 15 years found that 30 minutes/day of light-intensity physical activity was associated with significant reduction in mortality risk from cardiovascular disease (CVD) and cancer.
Similarly, only 10 minutes of moderate-vigorous physical activity was associated with reduction in CVD mortality risk.
Even brief trips up and down stairs would count toward accumulated exercise minutes as long as the intensity reaches a moderate or vigorous level of exertion.
Another 2018 study (Krause et al) followed the activity patterns of almost 5000 Americans over a 3-year period using an accelerometer (something like a Fitbit). I will summarize the study by presenting three fictitious characters.
Susan, Gail and Anne are the best of friends since high school. They are all turning 50 this year and joking about who will live the longest.
Lazy Susan is an accountant and does not do any type of physical activity. She parks her car close to the places she want to go to, takes the escalator and does not do much around the her apartment other than watch Netflix.
Gardening Gail is a stay at home mom; she’s never gone to a gym and hates the idea of exercising or walking on a machine. However, Gail loves her gardening and does chores around her house. She lives in a three story home where she has to climb up and down the stairs several times a day. She always chooses the stairs over the escalator and often walks to her favourite Satrbucks 15 minutes away from her house. Gail cannot seem to sit still for more than an hour before getting up to do something.
Active Anne loves staying active; she too does all her house chores such as laundry, cleaning and gardening, and also constantly has to go up and down the stairs in her house. However, instead of casually walking up, she makes a point of running up her stairs. In addition, she goes to the gym 3 times a week and does 30 minutes of elliptical or the treadmill and 30 minutes of weight training
The studies show that Lazy Susan who participates in less than 20 minutes of moderate or vigorous activity each day has the highest risk of death.
Gardening Gail who walks and gardens and participates in 60 minutes of physical activity per day cuts her risk of death by more than half of Susan’s.
Finally, Active Anne who gets at least 100 minutes (Almost 2 hours) of moderate or vigorous activity per day cuts her risk of death by 76 percent.
“… these results provide evidence that mortality risk reductions associated with moderate-vigorous physical activity are independent of how activity is accumulated.” (Krause et al 2018).
Clinical Relevance: PTs can now promote either long single physical activity (30-minute walk twice a day) or multiple shorter episodes of activity (e.g. 3-minute walk every hour).
The goal remains the same: to accumulate a minimum of 150 min. of physical activity a week. This new flexibility in the guidelines may be valuable for those who say they are just too busy or are unable to participate in 10 minutes of continuous activity due to various reasons.
So go ahead, make a goal of moving every hour. Go for a 3-minute walk, do jumping Jacks for 30 seconds, run up a flight of stairs. Park your car farther from your office or the shopping mall. Shovel snow.
The evidence now shows that every little bit counts!
References: Allison MK et al Brief Intense Stair Climbing Improves Cardiorespiratory Fitness. Med Sci Sports Exerc. 2017 Feb;49(2):298-307.
Krause WE et al Journal of the American Heart Association. 2018;7:e007678 Originally published March 22, 2018
Jefferis BJ et al Objectively measured physical activity, sedentary behaviour and all-cause mortality in older men: does volume of activity matter more than pattern of accumulation? Br J Sports Med. 2018 Feb 12. pii: bjsports-2017-098733.
Dohrn IM et al Replacing sedentary time with physical activity: a 15-year follow-up of mortality in a national cohort. Clin Epidemiol. 2018 Jan 25;10:179-186.
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