You don’t need to follow the “no pain, no gain” mantra to reap the health benefits of exercise, a new study shows.
Military-style boot camps that deliver fast-paced, high-intensity training (and chastise individuals for not working hard enough) may suit motivated exercisers who respond to commands to perform regimented bouts of exercise. But they’re unlikely to encourage previously sedentary people to get active. And, most importantly, to stay active.
My colleagues and I at the University of South Australia tested a different approach to encourage sedentary people to exercise. We found that a two-month program of moderately intense, self-paced exercise was enough to improve aerobic capacity and overall health.
Our results are published in the latest edition of Medicine & Science in Sports & Exercise.
Perceived difficulty
To measure the partipants’ level of physical exertion, we used the Borg rating of perceived exertion (RPE) – a 15-point self-rating scale that ranges from six (the lowest level, which is your resting state) to 20 (complete exhaustion).
We asked the participants to walk or run on a treadmill at a level of effort they perceived to be at 13 on the RPE scale, which is described as “somewhat hard”.
Our previous studies have shown that the perceived level of intensity correlates well with the actual intensity of the activity, measured by heart rate and oxygen uptake. And both measurements tend to increase proportionately.
So not only is it possible to reliably estimate the maximal aerobic capacity of the individual with a good degree of accuracy, it’s also possible to control and replicate the exercise intensity when it’s guided by the RPE.
Study design
We randomly assigned 26 sedentary men and women aged 20 to 54 to either a training group or control group. All participants completed a graded exercise test on a motorised treadmill to determine their aerobic capacity at the beginning and end of the eight-week period.
The exercise group performed 30 minutes of self-regulated training at RPE 13 level (somewhat hard) three times a week for eight weeks. The only factor we used to control the intensity of the exercise was the individual’s perception of the exercise intensity. All feedback relating to speed, heart rate and any other measures of exercise intensity were concealed.
We knew that the participants would be more likely to continue their exercise routines after the study concluded if they had a positive experience of being physically active. So every five minutes we asked whether they felt the level of exertion was pleasant or unpleasant, based on an 11-point scale from +5 (very good) to -5 (very bad).
Our instruction for the participants to work out at a somewhat hard intensity translated to moderate to vigorous sessions at around two-thirds of their aerobic intensity in week one.
The participants’ aerobic function improved throughout the program, meaning they could work physiologically harder at the same rating of perceived exertion. By week eight, the exercise group had increased their aerobic capacity by 17%.
Positive results
In terms of health benefits, the exercise group reduced their blood pressure by an average of 7% and their cholesterol dropped by 12%. There was no change in the no-exercise control group, except for a slight increase in their body mass index (BMI). The exercise group’s average BMI remained steady.
Perhaps the most important outcome was that the training group said the exercise to feel good or pleasant.
Another important feature of the study was that the intensity was left to the individuals to set for themselves. They were given the autonomy to control the speed and the gradient of the treadmill, according to their level of perceived exertion.
So if you’re trying to ease yourself into a new exercise regime, you don’t have to do it boot camp style. Self-regulated, moderate intensity exercise can deliver tangible health benefits.
For doctors and other health professionals, prescribing moderate-intensity exercise could have greater long-term health benefits than more intense (and potentially less pleasant) work outs.