There is no question that exercise is a critical component of any well-rounded health program. It is a great way to maintain a healthy weight, curb cravings, promote good blood sugar levels, keep your mind sharp and support your entire cardiovascular system.
While no one argues the incredible benefits of exercise, the types and duration of exercise are definitely sources of great debate. Many experts are still trying to find the optimal “dose” of exercise to prescribe for their patients.
To help answer this conundrum, Scottish researchers reviewed a variety of studies, including both population studies and clinical trials, to determine if high-intensity or low-intensity exercise is more effective at reducing cardiovascular risk and promoting heart health.
What the People Show
When reviewing epidemiological (or population) studies, the researchers found several interesting things. First, there’s no question that as exercise and activity levels increase, cardiovascular risk decreases.
Second, the Nurses’ Health Study found that moderate activity, even as infrequently as once a week, reduced risk of death by 22 percent. However, other studies have shown that exercise must be vigorous in order to produce a protective benefit.
Third, research seemed to concur that exercise, as long as it was done consistently, was the key. In fact, one study found that exercising just once a week reduced the risk of cardiovascular death in men by 39 percent and by 51 percent in women. Even more interesting was that increasing either duration or frequency of exercise did not confer any additional benefit, according to this study.
What the Labs Show
When the researchers looked the clinical trials, they found that only 1 out of 19 studies examined showed moderate-intensity exercise to be more effective than high-intensity when it came to decreasing cardiovascular health risk factors such as high blood pressure or cholesterol, blood sugar control or body weight.
Even given this, the researchers could not find consensus within the studies on “dose” of exercise. Some studies found that short, intense bursts were more effective, while others found that lower intensity for longer periods of time were better.
Researchers then looked at aerobic capacity, which is widely accepted as a good measure of physical fitness and has been shown to be a good predictor of death due to cardiovascular problems.
They found that high-intensity exercise (namely interval training) was better at increasing aerobic capacity than moderate exercise. As such, one could hypothesize that this meant high-intensity exercise is more cardioprotective.
Weaknesses and Conclusions
Before drawing their conclusions, researchers pointed out several issues with the studies.
First, the majority of the studies (especially the clinical trials) were done with either athletes or elderly or ill patients. The trick is correlating these two extremes to the majority of people who are likely somewhere in the middle in terms of health.
For example, walking may lower cardiovascular risk in elderly men, but not in young, healthy adults. The issue then becomes one of exertion.
Given this, the researchers drew these conclusions about exercise and heart health:
1. “Higher-intensity exercise offers greater cardioprotection and therefore should be encouraged in all patients where appropriate.”
2. “Even moderate-intensity exercise is sufficient to reduce cardiovascular risk.”
3. “Compliance is a major issue. No matter which type or intensity of exercise that the evidence deems the most effective, it will have no benefit unless the individual actually does it.”
Given this, they ultimately suggest, “Any physical activity is better than none, moderate intensity is better than low intensity and high-intensity exercise may be better still.”
Or, to put it another way, just get out there and get moving to the best of your ability to improve your heart health.
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