For Better Health, Improving Fitness May Be More Important Than Weight Loss

by Ashley Alexander on March 8, 2012

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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.

Jennifer March 8, 2012 at 4:48 pm

Bravo for addressing this important study at all.

Ashley Alexander March 8, 2012 at 4:51 pm

Thank you, Jennifer! It’s a complicated study so it was a challenge!

Angela March 8, 2012 at 10:06 pm

Thank you for the post! Currently wondering how different sports (e.g. cycling, swimming) fit into this, and whether they have the same benefits as running.

Ashley Alexander March 9, 2012 at 10:01 am

Thanks for reading! Although the fitness levels of the participants in this study were determined based on a treadmill test, my understanding is that good physical fitness can be achieved through many different activities. According to the CDC, cycling and swimming would both be good exercises for improving physical fitness (among others). As I had mentioned in the post, I think the key factor of good fitness is the development/maintenance of endurance. For more information and tips about fitness from the CDC, check out this link: http://www.nlm.nih.gov/medlineplus/exerciseandphysicalfitness.html

fitness March 9, 2012 at 8:19 pm

This is a complicated study. I think it does illustrate the importance of physical activity and in this case activity that has a cardiovascular conditioning effect.

Ashley Alexander March 12, 2012 at 11:23 am

I think it’s important to look at the whole picture when we consider our health, and that includes a larger spectrum of factors than just maintaining a normal BMI. Thanks for reading!

Emilie Reas March 10, 2012 at 2:36 pm

Thanks for a great summary of a really important finding. This addresses a major misconception in our society that body weight directly reflects health. Unfortunately, so many get preoccupied with losing weight, without understanding the greater long-term benefits of exercise and a healthy diet and lifestyle. It’s nice to see such a rigorously conducted longitudinal study, with an impressively large sample size and controls. However, I wonder if they considered diet at all? Although BMI didn’t correlate with death risk, weight and diet aren’t necessarily directly related. In fact, as a runner I find that I tend to put on weight during my peak training. Presumably, diet would significantly affect health and it would be interesting to see whether dietary effects correlated with or dissociated from fitness and BMI. I really enjoyed your post and hope coverage like this will result in a shift in our concern over body weight to focus on a healthy lifestyle.

Ashley Alexander March 12, 2012 at 11:33 am

I agree, being healthy is definitely multifaceted and that doesn’t always get a lot of attention. I don’t believe they looked at diet in this study. Because they were using data from an existing study, information about diet may not have been available. You raise a good point about diet though, since it is possible (and common) to not overeat in terms of calories, yet still be eating unhealthy foods. Thank you for reading and commenting!

Charles March 11, 2012 at 8:25 am

Good that you included the caveats of the study. Too few things written in newspapers or even blogs put science into context and show its limitations.

Ashley Alexander March 12, 2012 at 11:36 am

That’s actually an interest of mine, to communicate the limitations of research, because it’s important for framing the context of what the results actually mean. So often when news sources cover research, they focus on the big conclusion and gloss over everything else, and usually all that extra “stuff” is relevant. Thanks for reading!

Kristy E. March 13, 2012 at 10:46 am

It surprises me to learn that the pounds you carry may not be as harmful if your fitness level is up. Great job mentioning the limitations. As a woman, I’m extremely curious how the results of this study would differ (if at all) when pertaining to the opposite sex!

Ashley Alexander March 17, 2012 at 2:04 pm

Thanks for reading! I was also curious about how results might differ for women, especially since we naturally have more body fat than men. I guess we will just have to wait for more research!

Rick March 22, 2012 at 12:17 am

“The journal article also discussed that other research about weight changes and health status has yielded some varied and complicated results”
Is it possible to discuss “that” something? Usually we discuss an issue, but mention or state that [a proposition/fact]. Perhaps you mean one of the following?:

“The journal article also discussed other research about weight changes and health status that has yielded some varied and complicated results”

“The journal article also discussed some of the varied and complicated results that other research on weight changes and health status has yielded”

“The journal article also mentioned other research about weight changes and health status that has yielded some varied and complicated results”

“The journal article also stated/mentioned that other research on weight changes and health status has yielded some varied and complicated results”

Ashley Alexander March 26, 2012 at 12:24 pm

Thanks for the grammatical suggestion. When writing my posts I aim to be conversational, but sometimes the way we speak is not the best (or correct!) way to convey ideas in writing. Thanks for reading!

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