Adults whose exercise habits are in line with the U.S. recommended weekly physical activity guidelines are significantly less likely to die over the next decade or so than people who are inactive, suggest the findings from a study published recently in The BMJ.
That longevity benefit exists for people with chronic medical conditions, such as heart disease and type 2 diabetes, as well as for those who are generally healthy.
The study also found that the intensity of the physical activity may not matter, although the chance of a longer life appears to be slightly higher for people who engage in vigorous rather than light or moderate activity.
“Our findings support that the physical activity levels recommended in the 2018 physical activity guidelines for Americans provide important survival benefits,” the study’s authors conclude.
Those guidelines, which were updated in 2018, call for at least 150 minutes each week of moderate intensity aerobic activity (such as brisk walking, dancing or gardening), or at least 75 minutes each week of vigorous intensity aerobic activity (such as running, fast cycling or playing a competitive sport). They also recommend muscle strengthening activity of moderate or greater intensity at least twice a week.
Strong and growing evidence suggests that regular exercise helps prevent many chronic diseases, such as heart disease, type 2 diabetes and certain cancers, and that it may also reduce the risk of early death. A study published in June estimated, for example, that physical activity helps to avert 3.9 million early deaths every year, including more than 140,000 deaths in the United States.
But how much exercise is needed to reap those benefits? Specifically, is the amount prescribed in the U.S. guidelines sufficient? Only a handful of studies have looked at that issue, and their results have been inconsistent.
The current study is an attempt to get some clearer answers. It looked specifically for signs of an association between meeting the 2018 U.S. guidelines and the risk of death from any cause as well as from eight specific causes: cardiovascular disease, cancer, diabetes, Alzheimer’s disease, kidney disease, influenza/pneumonia, chronic lower respiratory tract diseases (such as asthma, chronic bronchitis and emphysema), and accidents/injuries.
For the study, researchers used data collected from a nationally representative group of 479,856 Americans, aged 18 to 85, who participated in the National Health Interview Survey between 1997 and 2014. The questions for that survey include ones about the participants’ physical activity, including how much time they spent each week doing aerobic and muscle-strengthening exercises.
Only 16 percent of the participants (76,384) fully met the recommended levels for both aerobic and muscle-strengthening activity, while 23.7 percent met the recommended level of aerobic activity only and 4.5 percent met the recommended level of muscle-strengthening activity only.
The participants were followed for an average of about nine years. During that time 59,819 died.
When the researchers compared the participants who didn’t meet the recommended activity levels with those who did, they found that engaging in sufficient muscle-strengthening activity was associated with an 11 percent lower risk of death from any cause, while engaging in sufficient aerobic activity was linked to a 29 percent lower risk.
Doing both types of exercise at the recommended levels reduced the risk even more — by 40 percent.
The data further revealed that people who met the aerobic activity guidelines were less likely to die during the study period from all eight causes of death. Those who met the muscle-strengthening activity guidelines were at a reduced risk of death from three of the causes: cardiovascular disease, cancer and chronic lower respiratory tract diseases.
“Although survival was found to be slightly better for those engaging in at least 75 minutes/week of vigorous physical activity, we also found enhanced survival to those who engaged in at least 150 minutes/week of light to moderate physical activity,” the researchers write.
Importantly, the study found that people with existing chronic medical conditions, as well as those who were healthy, tended to live longer when they met the physical activity guidelines.
“Exercise should be viewed as a cost-effective way of managing underlying chronic diseases, thereby reducing future mortality risk,” say the researchers.
“Appropriate type, intensity, and amounts of physical activity could be adapted based on abilities and the severity of the chronic condition,” they add.
Limitations and implications
This was an observational study, so it can’t prove a direct cause-and-effect relationship between meeting the physical activity guidelines and a longer life. In addition, the participants self-reported their physical activity levels. Such reports are not always reliable.
Still, this is a large study that followed people for a significant amount of time. It also took several steps to account for “reverse causation” — the possibility that the people in the study who exercised regularly were healthier to begin with.
“The study findings provide evidence to support the levels of physical activity recommended in the guidelines for greater survival,” the researchers conclude.
“Education programmes should include information on the health benefits of physical activity, and well-equipped facilities should be developed to facilitate increased physical activity among US adults,” they add.
FMI: You can read the study in full on The BMJ website. For tips and information (including videos) for getting you and your family more physically active, go to the U.S. Department of Health and Human Services “Move Your Way” website.