What Is The Ideal Weight for A Triathlete? BMI Impact!

When it comes to endurance sports like triathlon, body composition can make quite a difference in overall performance. If two athletes of the same height participate in a triathlon, if one is significantly heavier than the other then they will likely have very different results. Even if they both have about the same level of athletic ability.

Weight certainly isn’t the only factor that can affect our athletic performance. When it comes to triathlon, our height, width, arm length, and even posture can determine how fast we are able to complete the event.

The physical shape of our body, or how aerodynamic we are, can make a large difference in how hard an event will be. Throughout a race, we have to battle resistance from water during the swim as well as the wind on the bike and run.

There isn’t much we can do about our height or the length of our limbs. However, there are lots of articles out there about ways to decrease the amount of wind resistance, or drag, that is encountered on the triathlon course.

That brings us back to weight, which is the other performance factor that we can influence. By focusing on a balanced diet and tracking what we eat, it is possible to fine tune our body weight.  The best and safest way to use diet and exercise to gain or lose weight is to consult a nutritionist or other trained professional. Look online or ask around to find someone that works with your goals and within your budget.

So what is the ideal weight for a triathlete? A triathlete’s ideal weight is one where they are carrying very little excess body mass. At the same time, they must have enough muscle and fat stores available to keep them fueled throughout the entire event. The typical triathlete BMI (Body Mass Index) for women was 20.4 and for men was 21.3.

One way to tell if your body weight is close to the right number is to find or calculate your Body Mass Index (BMI). This index is simply a ratio that compares your weight to your height. A healthy BMI number is between 18.5 and 24.9. The lower the number, the less weight is present.

Keep in mind, however, that lower is not always better. Endurance athletes require a healthy amount of body fat in order to fuel themselves through long-distance events. In a 2014 study of hundreds of elite athletes, the average BMI for women was 20.4 and for men was 21.3. [source]

Anything much lower than that, and triathletes run the risk of bonking, or running out of energy in the middle of a race.

Remember, as we participate in long distance endurance events, the body relies on our fat stores as a fuel source. If those stores aren’t available then the next fuel source available is muscle, and we definitely don’t want to lose any of that!

How Do You Measure Your Body Mass Index (BMI)?

To find your BMI, simply take your weight in kilograms and divide it by your height in meters squared. Alternately, you can take your weight in lbs and divide it by your height in inches squared, then multiply that number by 703.

The formula looks something like this:                  BMI = (HEIGHT in meters) ÷ (WEIGHT in kilograms)2

The alternate formula looks like this:                     BMI = (HEIGHT in inches) ÷ (WEIGHT in pounds)2 × 703

Generally, a person is considered to be healthy if they have a BMI of less than 25. Keep in mind that this number can be misleading for endurance athletes. Because of the high concentration of muscle mass, their BMI could be in the higher range even though they are still very fit.

BMI is really just an indicator of whether or not your weight is in the right range for your height. It should not be taken as an absolute statement of our health. Only a complete physical by a doctor can tell for sure how healthy we are.

Are All Triathletes Skinny?

Not all triathletes are skinny, nor are they all super muscular. People with bodies of every shape and size are able to successfully participate in triathlons.  

Practically anyone can complete a triathlon, as long as they do enough training ahead of time. Big or small, short or tall; the sport of triathlon is made for us all.

When it comes to professional triathletes, they tend to be very lean and strong. Most of them have an ideal weight range that they shoot for by balancing their calorie intake with their training load. These pro athletes spend hours each day training in each of the three sports.

In between training sessions, they are fueling their bodies with high-performance foods. For most pros, their diets consist of lots of vegetables and lean meats. You probably won’t see a lot of them binging on high-fat items like pizza or fried chicken.

They choose to make adopt these healthy diets in order to keep their bodies at their ideal race weight. Eliminating extra body fat along with their training regimen enables the athletes to obtain peak performances while on the race course.

Also, check out our post “From Overweight to Triathlete- Examples & 25 Tips

How Does Body Shape Affect Triathlon Performance?

Just as no two triathlon courses look exactly alike, the same can be said about every triathlete. Because of the three very different disciplines involved in triathlon, each athlete’s size and shape has its advantages as well as its drawbacks.

Swimming is easier for taller people – they cut better through the water and have more energy stores to use. Especially in shorter races where explosive bursts of energy can make a difference.

However, the taller and heavier we are, the harder it is to propel ourselves forward in the cycling and running portions of the event. These sports are where shorter athletes have an advantage.

Most professional marathon runners and cyclists tend to be shorter than average.

Most of them have slender upper bodies and arms, but extremely lean and powerful leg muscles that they can keep churning for hours on end.

Is Triathlon Good for Weight Loss?

Training for a triathlon is one of the healthiest and most efficient ways to lose weight. The combination of the three sports works the entire body while burning a ton of calories.

If weight loss is your goal, then following through with a triathlon training program is a great way to find success.

In addition to the exercise component, having a target date for the triathlon is an extremely helpful tool to stay motivated. It is so much easier to stay focused on a goal such as weight loss when there is a defined time frame.

Triathlon training is good for more than just weight loss. It is also a great way to tone and build muscles.

Because triathlon works the entire body rather than just a single muscle group, we are able to work on being fit from head to toe.

Besides muscles, endurance sports like triathlon are also very good for our cardiovascular (heart) and respiratory (lungs) systems. The stronger these systems are, the less likely we are to be at risk for heart disease, diabetes, and even some forms of cancer. [source]

Remember, weight is just one small part of determining our success in triathlon. The most important factors by far are sticking to and following through with the daily/weekly workouts as we lead up to race day and properly fueling your body.

If you’re able to keep consistent with these, you’ll find success right around the corner!

Brad Birky

Brad Birky is an endurance athlete and trained chef who has qualified for and completed the Boston Marathon as well as multiple Ironman distance triathlons

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