Posted with permission from ZME Science

Exercising regularly seems to have a remarkable rejuvenating effect on the heart, according to a new study performed at the University of Texas Southwestern and the Texas Health Presbyterian Hospital Dallas. Researchers say moderate physical exercise can reverse the effects of sedentarism and aging which can cause problems like heart failure, provided you do it often enough.

The team investigated the effects of a training regime consisting of four to five workouts per week, each session lasting around 30 minutes plus warm-ups and cool-downs.

For the study, researchers recruited 53 middle-aged volunteers aged 45 to 64 who self-reported having a sedentary, lazy lifestyle. The participants were separated into two groups: one whose exercise program included moderate and high-intensity workouts, the other where participants performed weight training, balance work, and yoga.

During the first three months, the participants performed only three moderate exercise sessions per week. Once they built enough stamina, two high-intensity aerobic intervals were added to the first group.

At the end of the two-year study period, the differences between the two groups were strikingly clear. Those who had performed aerobic exercises showed an 18 percent improvement in their maximum oxygen intake during exercise and a more than 25 percent improvement in compliance, or elasticity, of the left ventricular muscle of the heart - the chamber that pumps oxygen-rich blood back out to the body. Those who did the yoga and weight sessions, however, did not show improved heart health.

One of the participants, aged 55, exercising on a treadmill. Credit: UT Southwestern.

The "winning" aerobic regime looked something like the following:

  • One of the weekly sessions included a high-intensity 30-minute workout, such as aerobic interval sessions in which heart rate tops 95 percent of peak rate for 4 minutes, with 3 minutes of recovery, repeated four times (a so-called "4 x 4").
  • Each interval session was followed by a recovery session performed at relatively low intensity.
  • One day's session lasted an hour and was of moderate intensity. (As a "prescription for life," Levine said this longer session could be a fun activity such as tennis, aerobic dancing, walking, or biking).
  • One or two other sessions were performed each week at a moderate intensity, meaning the participant would break a sweat, be a little short of breath, but still be able to carry on a conversation - the "talk test." In the study, exercise sessions were individually prescribed based on exercise tests and heart rate monitoring. The goal is to break a sweat but not get out of breath.
  • One or two weekly strength training sessions using weights or exercise machines were included on a separate day, or after an endurance session.

"Based on a series of studies performed by our team over the past 5 years, this ‘dose' of exercise has become my prescription for life," said senior author Dr. Benjamin Levine, Director of the Institute and Professor of Internal Medicine at UT Southwestern. "I think people should be able to do this as part of their personal hygiene – just like brushing your teeth and taking a shower."

Dr. Levine, shown here in front of his laboratory's hyper/hypobaric environmental chamber which simulates performance in environments such as space or deep diving. Credit: UT Southwestern.

Such benefits can be reaped as long as people start regularly exercising before age 65, a time when the heart still retains some plasticity and ability to remodel itself. The most important thing is to exercise frequently, the researchers stressed in the journal Circulation. Two to three times a week was not enough, the researchers found in a previous study. The intense workout was also extremely important, Levine said, even if it was just once a week.

"When the muscle stiffens, you get high pressure and the heart chamber doesn't fill as well with blood. In its most severe form, blood can back up into the lungs. That's when heart failure develops," said Dr. Levine, in a statement. 

The authors also recommend diversification in the training regime so there's a lower risk of getting bored and missing workouts. Tips include: performing the kind of exercise you have access to, do something enjoyable (tennis, basketball, ping-pong, etc.), alternating between low and high impact (cycling vs swimming, for instance). It's also best to keep it simple if you don't want to get overly complicated about it. Most of the volunteers who saw a marked improvement in their heart health chose to run, walk, or cycle.

"I think people should be able to do this as part of their personal hygiene – just like brushing your teeth and taking a shower," Levine said.