As people age they tend to do more sitting and less moving.

And for the average American, that sedentary trend begins all too early in life.

It's well-proven that an overly sedentary lifestyle raises the risks for brain and heart problems.

Absent enough activity or exercise, your heart muscle begins to shrink and stiffen, which boosts your risk of congestive heart failure.

Unsurprisingly, there’s good evidence that elite athletes — and serious exercise devotees — enjoy significantly lower rates of heart failure.

But many of us lack the time, motivation — or capacity — to go to the gym or pool, or to engage in sustained moderate aerobic exercises like running or biking.

Fortunately, new findings hold out hope of reversing the effects of relatively sedentary lifestyles in two years or less.

Better yet, you can do it without devoting hours to running, biking, or getting to and from a gym.

American/Australian study sees rapid reversal of couch-potato heart risk
Earlier this year, a team of scientists from Texas, Colorado, and Australia reported the encouraging results of a clinical trial involving sedentary middle-aged men.

Their findings suggest that people can reverse the heart damage caused by a sedentary lifestyle — specifically, shrinking and stiffening your heart muscle — with just two years or regular aerobic exercise.

The new study included 53 men who ranged in age from 45-64, and were basically healthy but engaged in no exercise or comparable physical activity (Howden EJ et al. 2018).

The participants were divided into two groups for the two-year controlled clinical trial:

  • Control group — Balance training, weight training, and yoga three times a week.
  • Exercise group — Moderate- and high-intensity aerobic exercise four or more days a week.

The exercise group practiced a “progressive” exercise regimen, during which they gradually raised the intensity of their workouts while their heart rates were monitored and recorded.

Men in the exercise group worked up to a series of high-intensity interval training sessions known as four-by-fours.

Those sessions involved four sets of exercise — lasting four minutes each — during which they reached 95 percent of their maximum heart rate.

Each four-minute exercise set was followed by three minutes of “active recovery” during which they reached 60 to 75 percent of their peak heart rate. (Read more about interval training and the high-intensity form below).

After two years, the exercise group enjoyed significant improvements in in both cardiac stiffness and the efficiency with which their bodies used oxygen, which is a standard marker of heart strength:

  • Improved their oxygen uptake by 18 percent, while the control group saw no improvement.
  • Reduced the stiffness of their heart muscle, while the control group showed no change in heart-muscle stiffness.

The study’s lead author — exercise expert Benjamin D. Levine, M.D. — described the implications of their findings: “We found what we believe to be the optimal dose of the right kind of exercise, which is four to five times a week, and the ‘sweet spot’ in time, when the heart risk from a lifetime of sedentary behavior can be improved -- which is late-middle age. The result was a reversal of [the effects of] decades of a sedentary lifestyle on the heart ...”.

And, as he said, “We found that exercising only two or three times a week didn’t do much to protect the heart against aging. But committed exercise four to five times a week was almost as effective at preventing sedentary heart aging as the more extreme exercise of elite athletes.”

High-intensity interval training offers a shortcut to maximum benefit
High-intensity interval training (HIIT) is a time-saving way to achieve the moderate- to high-intensity workout level assigned to one group in the newly published clinical trial.

These are some of the proven benefits of HIIT exercise routines:

  • Burns more calories
  • No equipment needed
  • Boosts aerobic capacity
  • The variety of exercises prevents boredom and gives every part of the body a workout.

And recent studies found that HIIT has the same beneficial effects on mitochondrial function seen in response to longer sessions of continuous moderate-intensity exercise (MacInnis MJ et al. 2017; Trewin AJ et al. 2018).

(Mitochondria are the energy "factories" in our cells, and improved mitochondrial function in response to exercise triggers beneficial changes that likely reduce the risk for chronic disease.)

HIIT routines alternate intense and light exercise — such as sprinting “all-out” as long as you can, and then walking quickly for about the same duration or distance.

Clear evidence indicates that HIIT workouts boost your aerobic health more quickly than lengthier workouts involving continuous moderate exercise. For more on that, see our 2014 report, titled Secret to Successful, Sustainable Exercise.

One of the first studies to confirm the comparative benefits of HIIT found that a four-minute HIIT workout was as effective as a 60-minutes of continuous moderate-intensity exercise (Tabata I et al. 1996).

Two years ago, a Norwegian-Australian team published their meta-analysis of 10 studies, which found that — among adults with heart disease, high blood pressure or obesity — HIIT workouts were significantly more effective than sustained moderate exercise for improving cardiorespiratory fitness (Weston KS et al. 2014).

And a European meta-analysis (review of multiple studies) published three years ago confirmed the benefits of brief HIIT workouts (Milanović Z at Al 2015).

The authors of that European meta-analysis analyzed 28 studies, and found that high-intensity interval training improved participants’ oxygen uptake or “VO2 max”. Higher oxygen-uptake capacities let you sustain higher levels of physical effort for longer. 

(The moderate-to-high-intensity exercise group in the new American-Australian clinical trial enjoyed improvements in their VO2 max scores, which probably helps explain their improved heart health and flexibility.)

Just as importantly, shorter, variable-intensity workouts — such as typical HIIT routines — make it easier to stick to a regular exercise regimen, versus time-consuming moderate-exercise routines such as running, biking, or visiting the gym.

If you’re interested in trying a HIIT workout, there are several excellent apps for mobile smart phones and tablets, and some good ones are free.

Most apps guide you through a core workout, and offer lower-impact, higher-intensity workouts, with warm-up and cool-down periods. There are even HIIT apps that allow you to add your own background music!

Last year, we reported on one of the most efficient, well-studied routines in 7-Minute Fitness HIIT, under the heading “Johnson & Johnson’s 7-Minute Workout”, where we provided a link to a New York Times article with HIIT exercise illustrations and links to a free downloadable NYT mobile HIIT app.

Learn more about abbreviated, high-intensity workouts in Pressed for Time? Try this Workout Shortcut, and What's the Best Energizing, Anti-Aging Workout?.


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