Book ReviewLifestyleVOLUME 18 ISSUE # 03

Move faster, live longer? A little more effort goes a long way

If there’s one public health message Americans have heard loud and clear, it’s this one:

Spend more time doing physical activity – at least 150 minutes a week, according to the latest guidelines. But hearing the message doesn’t mean we act on it. A whopping 25% of Americans don’t get any physical activity beyond what they do in their job, according to a CDC survey.

A new study suggests a different approach: You don’t have to do more. Just do what you’re already doing, but with a little more effort. The study builds on growing evidence that suggests exercise intensity matters just as much as the amount. So, something as simple as turning a leisurely stroll into a brisk walk can, over time, lead to significant reductions in your risk of cardiovascular disease. No additional moves, steps, or minutes needed.

Researchers at Cambridge University and the University of Leicester in England looked at data from 88,000 middle-aged adults who wore an activity tracking device for 7 days. The devices tracked both the total amount of activity they did and the intensity of that movement – that is, how fast they walked or how hard they pushed themselves.

The researchers then calculated their physical activity energy expenditure (the number of calories they burned when they were up and moving) and the percentage that came from moderate to vigorous physical activity. Physical activity means any and every movement you do throughout the day. Mostly it’s mundane tasks like shopping, walking to the mailbox, playing with your dog, or cooking. Moderate-intensity physical activity includes things you do at a faster pace. Maybe you’re walking for exercise, doing yardwork or household chores, or maybe you’re running late and just trying to get somewhere faster. You’re breathing a little harder and possibly working up a sweat.

Vigorous-intensity physical activity is usually an exercise session – a run, a strenuous hike, a tough workout in the gym. It can also be an exhausting chore like shoveling snow, which feels like a workout. You’re definitely breathing harder, and you’re probably working up a sweat, even in the middle of winter. Over the next 6 to 7 years, there were 4,000 new cases of cardiovascular disease among the people in the study.

Those who got at least 20% of their physical activity energy expenditure from moderate to vigorous activities had significantly less risk of heart disease, compared to those whose higher-effort activities were about 10%. That was true even for those whose total activity was relatively low. As long as higher-effort activities reached 20% of their total, they were 14% less likely to be diagnosed with a heart condition. And for those with relatively high activity levels, there was little extra benefit if their moderate and vigorous activities remained around 10%.