• A new study into the effects of fitness and weight has been published
• It reveals being fit and healthy might be more important than your BMI
• Being unfit appears to increase mortality risks by 2-3x

A new study into the relationship between cardiorespiratory fitness (CRF) and Body Mass Index (BMI) on cardiovascular disease (CVD) and all-cause mortality risk has revealed that being fit and healthy might be much more important than your overall body weight.

The study, published in the British Journal of Sports Medicine last month, was conducted by researchers from the University of Virginia and is a systematic review and meta-analysis of over 40 years of research into the relationship between fitness, weight, cardiovascular disease, and mortality.

The results include more than 398,000 observations across the research studied. Individuals were broadly grouped into fit versus unfit and then weight categories dubbed normal, overweight, and obese to create groups labeled normal-fit, obese-fit, and so on.

So what did they find out? And what could it mean for your fitness and health goals?

Study lays bare the dangers of being unfit

According to the results, there was no “statistically different risk of mortality” between those who were overweight-fit, obese-fit, or either of the test groups. Unfit individuals who were either normal weight, overweight, or obese all shared the same two-fold risk in all-cause mortality versus normal weight-fit people.

While there was no increase in the risk of CVD in any of the fit categories, regardless of weight, the risk of CVD in unfit people was elevated by 2-3 fold regardless of whether they were normal weight, overweight, or obese.

What does this mean? Broadly, being fit seems to help defend against death, either from CVD or all causes, regardless of your overall weight or BMI. Conversely, weight is much less of a factor than being unfit in increasing those risks, with participants in every weight category at broadly the same risk regardless of their weight.

So if you’re looking to make a dent in your fitness in 2025, or you’re starting to think about making lifestyle changes to live a longer, healthier life, this study suggests you might be better off out walking 10,000 steps, hitting the bike or treadmill, or doing some circuits, rather than watching your weight and counting calories.

Of course, the usual fitness caveats apply. Being overweight can still have consequences, like increased joint stress, so this isn’t a license to start packing on the pounds. But focussing on your fitness, rather than how much you weigh is a good place to start. If you’re lifting weights or building muscle through endurance, your weight might even increase over time, too.

With 2025 just around the corner, maybe it’s time you finally grabbed that best fitness tracker you’ve been thinking about.

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