Does a youth misspent lounging and lazing condemn middle-aged folks to a future of bad heart health?
Maybe not, a new, small study has found.
People in their 50s and early 60s can regain the heart health of someone decades younger through a regular and reasonable aerobic exercise program, no matter how long they've been inactive, the study authors said.
Middle-aged couch potatoes who worked out four or five days a week -- including a couple of days of high-intensity aerobics -- for two years experienced a notable decrease in the stiffness of their heart muscle, the researchers found.
A more flexible heart means less risk of heart failure as one ages, explained lead researcher Dr. Benjamin Levine, founder and director of the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital in Dallas.
"I was astounded at how well this seemed to improve the flexibility and compliance of the heart," Levine said. "The key to a healthier heart in middle age is the right dose of exercise at the right time in life."
A sedentary lifestyle in late middle age is known to increase the risk of heart failure by allowing the heart muscle to shrink and stiffen, the researchers said in background notes.
What wasn't known is how late in life a person can act to reduce that risk, and how much effort this would require.
Earlier experiments showed that by the time men and women hit the 70s, intense exercise will do nothing to improve their heart health, Levine said. These studies also found that someone who only works out a couple times a week gains little when it comes to their heart.
"We found casual exercise, two or three days a week, was simply not enough to preserve the youthfulness of the structure of the heart," Levine said. "That doesn't mean it had no benefits, but it wasn't enough to preserve that youthful rubber-band-like compliance."
To see if a higher dose of exercise at a younger age would help, Levine and his colleagues recruited 61 people between the ages of 45 and 64 who were healthy but stuck in a low-energy sedentary lifestyle.
These volunteers were assigned to two different groups. One group engaged in two years of training that included four to five days of exercise each week, while the other group took part in regular yoga, balance training and weight-lifting workouts.
The researchers eased the exercise group into its routine during the first couple of months to avoid injury, Levine said, but eventually the participants adopted a regular set of workouts that included:
Two days of high-intensity intervals: Exercises where a person works out as much as possible for four minutes, and then spends three minutes in active recovery before hitting it again, four times in a row.
One day of long moderate-intensity exercise: At least an hour spent in some activity that raises the heart rate, be it square dancing, tennis, cycling or a brisk walk.
One or two days featuring 30 minutes of moderate-intensity exercise.
The regimen also included two recovery days that followed interval training, consisting of 20 to 30 minutes of walking or light aerobic activity.
"People generally like interval sessions because they don't last as long," Levine said. "You can work out hard and then recover, and it feels really good."
The participants were encouraged to use lots of different exercise equipment (stationary bikes, treadmills, elliptical trainers) and engage in outdoor exercises (running and cycling) to keep themselves motivated and interested, Levine said.
After a while, all in the aerobics group transitioned to what Levine calls their weekly "maintenance dose" -- one high-intensity interval session, one long session, a couple of regular base-training sessions and a recovery day, along with some strength training.