In public health, it’s no secret that chronic diseases are enemy number one these days. In the United States, cardiovascular disease (CVD) is the leading cause of death for both men and women followed closely behind by cancers, with diabetes also making an appearance in the top ten. Obesity has been found to be a common risk factor for all of those serious health problems, and as a result, strategies for preventing chronic diseases are often centered on weight loss. New research, however, suggests that increasing physical fitness may be the key to a longer and healthier life—regardless of how many pounds you’re carrying.
The new study, published in the American Heart Association’s journal Circulation, looked at how changes in fitness level and body mass index (BMI) over time impacted the risk of death. Using medical data from an existing longitudinal study, the researchers assessed the fitness levels and BMIs of more than 14,000 men and how changes in those measures impacted their risk of death from CVD and other causes.
All of the subjects had at least two very thorough physical exams that occurred several years apart. At the initial visit, all of the men were healthy and disease-free though, based on BMI, slightly overweight. As part of the exam, the men underwent a treadmill test in order to gauge their cardiovascular fitness. Fitness level was calculated for each individual by plugging in the duration of their treadmill test and the maximum speed that was reached into a formula. Then at their last visit, the men participated in the same treadmill test and new fitness levels and BMIs were calculated.
Each participant’s fitness level was compared from the first test to the second test, as were each man’s BMI scores. Comparing the starting and ending fitness levels found that some men maintained their fitness while others showed improvements or declines, and similar changes were also found when comparing the BMI scores. The fitness and BMI statuses were then matched with the data on death rates and causes of death. In their analyses, the researchers controlled for risk factors that developed from the first assessment to the second like lifestyle behaviors (e.g., smoking or alcohol consumption) and illnesses (e.g., high blood pressure) in order to get a clear picture of how fitness and weight changes impacted risk.
The results? Even if they showed a weight gain between the two doctor visits, the men who maintained good physical fitness and the men who improved their fitness had a significantly decreased risk of death from all causes, including death from CVD. On the flip side, the men who showed a decline in fitness from exam #1 to exam #2 were found to be at much greater risk for death regardless of whether or not they lost weight.
In making these results relevant to everyday life, it’s important to recognize how fitness was defined for this study. Since fitness was based off of performance on the treadmill test, the notion of good “fitness” has more to do with physical endurance than with simply being active. It seems likely that the reduced risk of death, particularly death from CVD, observed in the men who had good levels of physical fitness is linked to this notion of physical endurance and how that helps to keep the heart healthy.
But wait—don’t take up daily jogging and forego healthy eating, just yet. As with most studies, there are limitations to this research. First, the study only included men meaning that it’s unclear whether or not good fitness levels can have the same protective benefits on health for women. Plus, the men included in the study were all initially considered overweight by BMI cut-offs, so it’s also uncertain whether or not individuals who fall into the obese range would see the same results.
The journal article also discussed that other research about weight changes and health status has yielded some varied and complicated results, and this is the first study of its kind to look at how a person’s fitness level may affect that relationship. But while these findings are new and somewhat limited, the study marks an important milestone in public health. By proposing that improving and maintaining fitness throughout life can be just as beneficial as weight loss, this study opens the door for more research and possibilities to help prevent chronic disease.