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How much exercise is needed for maximum heart benefit?



All activity counts

Exercise physiologists speak of NEPA – nonexercise physical activity – such as taking out the garbage. Swedish investigators followed more than 4,200 individuals for an average of 12.5 years and found that high NEPA activity was independently associated with a 30% reduction in all-cause mortality and a 27% lower risk of a first cardiovascular disease event, compared with low NEPA. High NEPA in regular exercisers was associated with a lower rate of metabolic syndrome than in low-NEPA regular exercisers (Br J Sports Med. 2014 Feb;48[3]:233-8).

Don’t just sit there – stand!

The current federal physical activity guidelines place a new emphasis on the detrimental effects of sitting. A report on more than 221,000 participants in the Australian 45 and Up Study, with close to 1 million person-years of follow-up, demonstrated a linear inverse relationship between standing time per day and all-cause mortality. In a multivariate analysis adjusted for potential confounders, individuals who stood for 2-5 hours per day had a 10% lower risk of all-cause mortality than did those who stood for less than 2 hours. Standing for 5-8 hours was associated with a 15% relative risk reduction. And standing for more than 8 hours daily was linked to a 24% reduction in risk (Prev Med. 2014 Dec;69:187-91).

And it’s not just total daily sitting time that’s a risk factor. Prolonged, uninterrupted sedentary time was also associated with a dose-dependent increase in all-cause mortality in a prospective cohort study of nearly 8,000 U.S. adults (Ann Intern Med. 2017 Oct 3;167[7]:465-75).

“If you can’t walk around, talk to your patients standing up. That activity of getting out of your chair is lifesaving,” the cardiologist advised.

Get strong

Muscle-strengthening activity on at least 2 days/week is recommended in the federal guidelines because it’s independently associated with decreased all-cause mortality, even in individuals getting sufficient aerobic exercise, as shown in a large national study with 15-years’ follow-up (Prev Med. 2016 Jun;87:121-127).

“As we get older, we tend to forget about muscle. I work with the National Football League. These folks are pretty strong, but we never see diabetes in these very big players, who are often well over 300 lb. They’ve got a lot of muscle. If you want to prevent diabetes, be strong. It’s a very important factor,” Dr. Vogel said.

For the time constrained

Jogging is more time-efficient than brisk walking as a way to attain the maximum cardiovascular benefit of exercise. And the so-called “Weekend Warrior” study of nearly 64,000 U.K. adults showed that it’s okay to cram the full week’s worth of exercise into one or two sessions and be done with it. Compared with the inactive study participants, the weekend warriors had a 40% reduction in cardiovascular disease mortality, while individuals who split their physical activity up into three or more sessions per week had a nearly identical 41% relative risk reduction (JAMA Intern Med. 2017 Mar 1;177[3]:335-42).

Interval training is a standard way for athletes in training to improve their endurance by alternating short, intense exercise with brief recovery periods. It’s also a time saver: In one classic bicycling study, physically active men were randomized to standardized 2-week programs of sprint interval training or high-volume endurance training on the bike. The training time required to pass a rigorous cycling time trial test was 90% lower in the interval training group (J Physiol. 2006 Sep 15;575(Pt 3):901-11).

The same principle is applicable to the nonathlete interested in physical activity for heart health.

“When I run a couple of miles, I walk for 5 minutes, then maybe run for three-quarters of a mile, then walk again, then run. In interval training you get your heart rate up, and you drop it down. It’s a very good form of exercise. As a vascular biologist I know that if you put endothelial cells in a Petri dish and spin them real fast continuously, you will not get as good an improvement in endothelial function as if you spin the dish, stop it, spin it, stop it,” Dr. Vogel said.

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