“Your heart doesn’t care what kind of exercise you do.”

You may have heard something along those lines if you’re a triathlete.

You may have read an article about why triathletes don’t need long swims because their hearts are well prepared by cycling and running. Maybe you’ve heard someone say that as long as you’ve been training in other sports, your heart will be ready for triathlon.

There’s some truth to this idea, but it’s more complicated than most people realize.

Why Your Heart Isn’t as Well Rounded as You Might Think

Different sports change your heart in slightly different ways.

Endurance sports tend to make your heart wider, heavier, and thicker – a process called eccentric hypertrophy.

Strength sports like weightlifting tend to cause concentric hypertrophy. The heart gets heavier and thicker, but not wider. Some recent research has challenged this idea, but it’s generally considered true.

Different endurance sports also change the heart in various ways. Swimmers have hearts that are very different from cyclists and runners. Cross-country skiers, rowers, and other endurance athletes all have unique hearts.

Triathletes are a different breed. Our hearts are a combination of swimmers, cyclists, and runners. Basically, you’ve got a hybrid engine for a heart.

What This Means for Your Triathlon Performance

There’s never been a study examining whether or not having a swimmers heart makes you less good at cycling or running, or visa versa.

However, it’s possible that having a heart that is overly adapted to one sport may mean you’re less prepared for one of the other two.

It seems logical that if you want to maximize your triathlon performance, you should grow the heart of a triathlete.

How to Grow the Heart of a Triathlete

Swim. Bike. Run.

It’s that simple.

If you swim, bike, and run enough, your heart will adapt to all three sports. Intensity within the three disciplines also matters. Easy and moderate training doesn’t change the heart very much. It takes harder, interval type training to produce the largest changes in heart function.

When you’re trying to harness the motivation to get through a long, hard set of intervals at the pool, on the road, or on the track, remember that not only are you on your way to a PR, you’re on your way to a strong triathlete heart!

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