One of the polarizing debates in the running world is whether there is an ideal running weight. The concept of an ideal running weight or ideal racing weight isn’t necessarily new, but it seems to resurface in popular searches every couple of years.
It’s not uncommon for runners to have a complicated relationship with food and weight. After all, many runners are initially drawn to the sport as a means to lose weight or maintain a healthy weight.
Other runners notice performance improvements when they do lose weight, or, may see slower race times when weight is gained. But, is there an ideal running weight? Can a runner be too thin? Is there a target body fat percentage or BMI for runners?
If you’re trying to optimize your health and performance and have questions about ideal running weight, keep reading to learn if there is an ideal running weight and what factors and body measurements you should care about as a runner.
In this guide, we’re going to look at:
- Why Do Runners Care About An Ideal Running Weight?
- Is There An Ideal Running Weight?
- Is There An Ideal Body Fat Percentage for Runners?
- What Is The Ideal Body Fat Percentage For Runners?
- Is There An Ideal BMI For Runners?
- How Much Should I Run According To My BMI?
- Can A Runner Be Too Thin?
- How To Find Your Ideal Running Weight
Let’s dive in!
Why Do Runners Care About an Ideal Running Weight?
It is true that your body weight can impact your performance as a runner to some degree. The heavier you are, the harder your body has to work to move from point A to point B.
That said, “weight” isn’t the be-all-end-all metric we often make it out to be. Bodyweight includes things like muscle, bone, and blood, which are considered lean body mass. Runners never want to lose lean body mass, as doing so can be detrimental to overall health and athletic performance.
On the other hand, body fat doesn’t contribute to enhancing exercise performance. While a certain amount of body fat is required to insulate the body, cushion organs, and maintain normal hormonal functioning, excess body fat can act somewhat like dead weight and can reduce athletic performance.Additionally, since your body absorbs the forces of your mass with each stride, lowering your weight by losing fat can reduce these forces, potentially lowering the risk of injuries.
Is There an Ideal Running Weight?
The short answer is no, there is no ideal running weight or ideal racing weight. Rather, there is a healthy or ideal weight range for every individual runner based on their unique body composition and morphology, health status, age, and sex.
What Is the Ideal Runner’s Body Fat Percentage?
The most important biomarker related to an ideal running weight that runners should pay attention to is body fat percentage. A runner’s body fat percentage is a far more meaningful measurement of body composition than BMI.
Body fat percentage can be estimated through a variety of means such as hydrostatic weighing, DEXA, bioelectrical impedance (body fat scales or handheld devices), circumference measurements, or skinfold measurements.
The accuracy of your body fat percentage is dependent on how you obtain the measurement.
For example, bioelectrical impedance is sensitive to your hydration status. If you step on a body fat scale, take your reading, and then drink a large glass of water and re-weigh yourself, you might get significantly different readings for your body fat because water changes the speed at which the electrical impulse travels through your body.
The key to getting more accurate body fat measurements is to follow the directions and protocol for the method you are using to a T and to stay consistent in the way you measure your body fat.
For example, if you are using a body fat scale, weigh yourself at the same time each week according to the recommended instructions.
Is There an Ideal Body Fat Percentage for Runners?
The ideal body fat percentage for runners is largely dependent on sex. The following are the typical body fat ranges given for men and women:
- Essential Fat: < 5 percent
- Athletes: 5 to 10 percent
- General Fitness: 11 to 14 percent
- Good Health: 15 to 20 percent
- Overweight: 21 t0 24 percent
- Too High: > 24
- Essential Fat: < 8 percent
- Athletes: 8 to 15 percent
- General Fitness: 16 to 23 percent
- Good Health: 24 to 30 percent
- Overweight: 31 to 36 percent
- Too High: > 37
Is There An Ideal BMI for Runners?
Healthcare literature and scientific studies often cite BMI, but ultimately, BMI is not as useful to runners as it is often cracked up to be.
BMI, or body mass index, is simply a value that represents a comparison of your weight to height. BMI has nothing to do with your body fat percentage or your body composition.
To calculate your BMI, use the following formula:
BMI = (weight in kg) / (height in m)2
For example, if you weigh 75 kg (165 pounds) and stand 5 feet 7 inches tall (1.7 meters), your BMI = 75 / 2.89 = 25.9 kg/m2
For more info, check out our BMI calculator.
Essentially, a strong, muscular runner can have a much higher BMI than a height-matched thinner runner who has much more body fat and little muscle. However, the muscular runner may be healthier and a much faster runner.
Moreover, many muscular runners and other athletes are categorized as “overweight” using the standard BMI interpretation chart simply because those ranges were developed to represent average adults, not athletes with a muscular build.
For that reason, be careful not to ascribe too much significance to your BMI.
That said, this is how BMI is interpreted:
- Below 18: Underweight
- 18-24: Normal
- 25-30: Overweight
- 30-34: Obese
- 35+: Morbidly Obese
How Much Should I Run According to My BMI?
Many runners wonder how much they should run based on their BMI, particularly because healthcare providers may use your BMI as an indicator of your ideal running weight.
For example, if you are carrying excess weight and have a BMI in the overweight category, your doctor may recommend you lose weight such that your BMI lands you in the normal weight category.
Again, however, it’s important to consider your overall body composition and muscle mass.
Body fat percentage is a much better metric to consider when guiding your weight loss or “ideal running weight” because it measures what actually matters for health and running performance—body fat.
Remember, BMI is simply a comparison measurement of your height relative to your weight. It is not an assessment of your body composition.
With that said, BMI can be used to inform how much you should run to some degree. The higher your BMI, the more stress and load your joints, bones, and connective tissues take with every stride. This can potentially increase your risk of injury.
If you are a beginner runner and have a high BMI (26 or above), you may want to incorporate more low-impact cross-training exercise, such as cycling, rowing, swimming, and the elliptical machine into your workout routine rather than increasing your running mileage aggressively.
Alternating run days and cross-training days will help give your body time to adapt to the stresses of running and recover between high-impact runs.
On the other end of the spectrum, if your BMI is low, focus on strength training to build muscle and increase your caloric intake to support your running. Consider seeking guidance from a registered dietitian or sports nutritionist and decreasing how much you are running.
Runners with a low BMI are more prone to injury, particularly if they are in a negative energy balance (burning more calories than the number of calories they are consuming).
Can A Runner Be Too Thin?
Absolutely. The whole concept of an ideal running weight centers on the fact that there’s an optimal weight range where each individual runner will be their healthiest, fittest self.
Below this ideal range, a runner is too thin. This means that their body fat percentage has dipped into the essential body fat levels or below, and the body lacks the strength and resources it needs to run well (figuratively and literally).
Dropping below your ideal running weight can affect your hormones and put your body into a state of chronic deprivation and stress.
For example, female runners who restrict calories too aggressively and/or have inadequate caloric intake to support their running volume can suffer amenorrhea or cessation of menstruation.
Amenorrhea not only leads to infertility, but it can also be detrimental to bone health and increase the risk of injuries, such as stress fractures.
It’s usually recommended that runners maintain a body fat percentage of at least 14% for women and 6% for men, or a BMI of 18.5 kg/m2, unless otherwise specifically instructed by a healthcare provider.
How to Find Your Ideal Running Weight
Even though there is no specific ideal running weight, you can find an ideal running weight range by considering your frame size and your target body fat percentage.
Remember, however, there are no absolutes when it comes to ideal running weight. Some runners find they feel stronger and more powerful when they carry more muscle, and sometimes even more fat.
Don’t be beholden to your numbers either way. The best advice is to listen to your body: heed your hunger cues, fuel with nutritious foods, train smart but respect your limits, and try to respect the equilibrium spot your body finds for your ideal running weight range.
If you are interested in reading up on how to fuel your body for running, take a look at our running nutrition guides!
Related: Ideal Body Weight Range Calculator