A recent study that associated levels of physical activity higher than the generally prescribed 30 minutes a day with a reduced risk of five major diseases appeared both promising and invigorating until eager exercisers read the fine print.
Public health baselines, for decades, have recommended 30 minutes of moderate-intensity physical activity at least five days a week — about 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity each week. Yet the study in The BMJ advised it would take five times as much activity to lower the risk of breast and bowel cancer, heart disease, stroke and type 2 diabetes.
Researchers in the United States and Australia used data from 174 studies — or more than 149 million total person-years of follow-up — between 1980 and 2016 to determine the rewards of daily physical activity, whether routine chores, occupational activity or recreation. The study suggested between 3,000 and 4,000 metabolic equivalent minutes each week, with diminishing effects beyond that.
The typical American’s response: What’s a metabolic equivalent? Well, a single MET is similar to the oxygen cost of sitting patiently in a doctor’s office. Sounds easy so far, but getting to 3,000 is a climb — as in, the study’s estimate, climbing stairs 10 minutes, vacuuming 15 minutes, gardening 20 minutes, running 20 minutes and walking or cycling 25 minutes. All of that, every day.
Examples of “moderate” exercise versus “vigorous” exercise include:
[huge_it_gallery id=”19″]
A few examples of building your MET count:
(less than 3 METs): walking slowly, sitting at a computer (1.5), fishing while sitting (2) and playing an instrument (2-2.5).
Moderate (3 to 6 METs): walking briskly about 4 mph (5), vacuuming or mopping a floor (3-3.5), mowing the lawn (5.5), bicycling 10-12 mph (6), tennis doubles (5).
Vigorous (more than 6 METs): walking or hiking 4.5 mph (7), jogging at 6 mph (10) shoveling (7-8.5), carry a heavy load (7.5), bicycling 14-16 mph (10), playing basketball (8), casual soccer (7), tennis singles (8).
There is hope, however, for the 30-minutes-a-day exerciser because the study encouraged MET inflation by using self-reported data: It includes all physical activity, even incidental movement at work (walking to the printer or lifting a box of files). But the study’s estimates of 13-16 hours of brisk walking or 6-8 hours of running each week as a disease fighter leaves most of us in the dust.