Is BMI Best? Measuring for Runners

Whether you’re a seasoned runner or just starting out, it’s natural to think about your progress and how to measure it. There’s many different ways of doing so, but some of them may not actually be particularly helpful for runners, especially if you are exercising to try and combat anxiety. BMI – or Body Mass Index – is one such body-scoring measurement which for runners, may do more harm than good.

What is BMI?

BMI takes into account your weight and your height, and can therefore be more useful than simply looking at weight alone. After all, a tall person is naturally going to be heavier than a short person. The formula for BMI is weight (kg) divided by height squared (m) and a healthy BMI ranges between 19 and 24, with under 19 being considered underweight and over 24 as obese. For the average person, this is a good way to get a quick idea if you’re about the right weight. However, it fails to take account of muscle mass, meaning that BMI may not be useful for runners and other athletes.

Should runners worry about BMI?

Your BMI score should not be the “be all and end all’ measurement of health, particularly for runners, as people run for many different reasons, not just for body condition. Muscle weighs more than fat, so a BMI of a well-muscled person can turn out “overweight” and gives an unrealistic impression of their “health”. This is most obvious in people such as bodybuilders or lifters who are very muscle bound, but it is also true of runners. Even within the category of “runner” there is wide variation – sprinters have more muscle than distance runners by virtue of them needing to hit higher speeds and to do so faster.

Other measures of fitness

For most runners, the most useful way to measure their body condition is through what it can perform, so looking at your time splits or heart rate can be more useful, or simply how tired or happy you feel after completing a run. If you are looking for a way to measure your body’s composition though, calculating body fat percentage may be more relevant than BMI. This can be done using calipers or special body fat % scales. As you lose fat and gain muscle, your weight will change but may not always go down, because lean muscle is more dense than fat and weighs more.

Taking measurements and tracking progress of your statistics can be really important for runners to check how you’re improving or working towards your goals; just make sure to pick relevant measures which will truly reflect your capabilities as an athlete.