“Either work hard or you might as well quit,” MC Hammer sings in “U can’t touch this.” (It comes right before “That’s word because you know U can’t touch this (oh-oh oh oh-oh-oh) Break it down.”)
Yes, he’s a brilliant rapper, but he was wrong when it comes to exercise. The research shows that for your health, it’s far better to do something light and easy — anything — than to be sedentary. Still, I’ve been struck by a phenomenon I’ve now observed twice in hotel gyms: A guest comes in, gets on the treadmill or the bike, and hangs out there for a half hour or more without ever going fast enough or hard enough to break a sweat or breathe heavily.
I have to confess, I’m somehow disturbed by this. Have their doctors warned them not to exert themselves? Or do they just not know how much more they could be getting out of their exercise time? I’ll never be intrusive enough to ask, but next time I see one of those guests, I’ll be thinking of a study just out in the medical journal BMJ Open that smacks of MC Hammer’s maximalism. From the press release:
Fast walking and jogging halve development of heart disease and stroke risk factors
But an hour’s walk every day makes no difference: intensity rather than duration is what counts
Daily activities, such as fast walking and jogging, can curb the development of risk factors for heart disease and stroke by as much as 50 per cent, whereas an hour’s daily walk makes little difference, indicates research published in the online journal BMJ Open.
The findings indicate that it is the intensity, rather than the duration, of exercise that counts in combating the impact of metabolic syndrome – a combination of factors, including midriff bulge, high blood pressure, insulin resistance, higher than normal levels of blood glucose and abnormal blood fat levels – say the authors.
The authors base their findings on more than 10,000 Danish adults, between the ages of 21 and 98, who were initially assessed in 1991-94 and then monitored for up to 10 years. All the participants were quizzed on the amount of physical activity they did, which was categorised according to intensity and duration.
It was not only the amount of exercise, but also the intensity which helped curb the likelihood of developing the syndrome.
After taking account of factors likely to influence the results, fast walking speed halved the risk, while jogging cut the risk by 40 per cent. But going for an hour’s walk every day made no difference.
“Our results confirm the role of physical activity in reducing [metabolic syndrome] risk and suggest that intensity rather than volume of physical activity is important,” conclude the authors.
Hmmm. I turned for guidance to Dr. Eddie Phillips, director of the Institute of Lifestyle Medicine at Harvard and Spaulding Rehabilitation Hospital. He started with the basics: The federal guidelines for physical activity are five years old now, and this new study doesn’t contradict them. The guidelines recommend 150 minutes of “moderate intensity” exercise, and that “means working hard enough that you have trouble singing.”
It’s clear, he said, that any kind of activity is better than a sedentary life, but that moderate intensity is better than the low intensity I saw in those hotel gyms. And now there’s an emerging literature on “high intensity interval training” that points up the benefits of pushing yourself really hard for brief periods. As he reads the new study, “it tells you to do moderate intensity at least.”
Might there, I asked, be a great many people who should not do even moderate intensity? (And all staying where I do?)
There are people with cardiac disease who get symptoms when they work moderately, Dr. Phillips said, and the formal medical screening for whether a patient should exercise also checks for lung disease; and patients with asthma or emphysema may get too out of breath.
But when he screens someone, he said, “I go back to the risks of being sedentary.” The question often needs to be flipped, he said, from “Is it safe to exercise?” to “Is it safe to remain sedentary?” And the answer to that tends to be, “No, of course not.”