Feeling a bit bloated and sluggish after Thanksgiving weekend? A major study just out in the journal JAMA Internal Medicine offers an added nudge to get back on the exercise wagon. How fit you are even in your 20s, the study finds, can dramatically affect your risk of heart disease and death well into middle age.
So dramatically, in fact, that every minute matters.
Imagine you’re doing a stress test on a treadmill. Every two minutes, the machine makes you go faster and at a steeper incline. The first few minutes are no sweat — you’re walking, then trotting, then jogging — but soon you start to suck air, and finally hit the point that you can bear no more. (Or you may reach the 18-minute maximum, if you’re superhuman.)
Say you did that test in your 20s. Now fast-forward 25 years. The study found that every extra minute you could last on the treadmill meant you were at a 15 percent lower risk of death over that quarter-century, and at a 12 percent lower risk of harmful effects of heart disease, including stroke and heart attack.
“That’s a lot,” I found myself saying in a phone interview with the study’s two lead authors, Dr. Ravi V. Shah, of Harvard Medical School and Beth Israel Deaconess Medical Center, and Dr. Venk Murthy of the University of Michigan.
“We were surprised too,” Dr. Shah said.
“Two, three, four, five minute differences are not uncommon,” Dr. Murthy said. “That adds up. That’s 15 percent per minute — it’s pretty substantial.”
Though, of course, it must be noted that the overall risk of heart disease and death are relatively low in such a young population. Among the 4,872 people in the study, 273 died, but 200 of those deaths had no relation to heart disease. And just 4 percent of the study’s subjects had a “cardiovascular event” like a heart attack.
Still, the results cast new light on just how much fitness matters for heart health — even in our 20s, when many of us can still get away with a sleepless all-nighter or an all-weekend TV binge.
This new research is the first large study to examine people in their 20s onward over such a long period, the lead authors say, and underscores the importance of starting good fitness habits early — not just in later years, when the health price of inactivity is already well known.
The study also found that the heart benefits of fitness held true independent of weight and other heart risk factors. That suggests, Dr. Shah said, that “being fit is important for everyone, not just for people who are trying to lose or maintain weight.”
The study — an epic endeavor that began back in the mid-1980s and was led by four universities, including Harvard and Johns Hopkins — also suggests that early trajectory matters. That is, typical as it may be, it is not a good idea to let your fitness decline in your 20s.
Nearly 2,500 of the subjects underwent a second treadmill test just seven years after the first. For every minute less that they could last compared with their first test, their risk of death in the coming years went up by 21 percent, and their risk of heart disease by 20 percent.
And one other, particularly fascinating finding: Fitness as reflected by treadmill performance did not seem to matter for an accepted measure of heart health, the accumulation of calcium deposits in the arteries that supply the heart. Continue reading