Long runs can build speed, endurance, and muscle mass—but marathon training (more so than weight training!) has serious brain boons
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Marathon runners know that the mind can be your biggest ally (especially around mile 23), but it turns out that running can also be a friend to your brain. A new study from the University of Kansas found that running actually changes the way your brain communicates with your body more than other workouts.

Researchers examined the brains and muscles of five endurance athletes, five weight lifters, and five sedentary folks. After setting up sensors to monitor their quadricep muscle fibers, the scientists found that the muscles in runners responded more rapidly to brain signals than the muscles of any other group.

So all those miles you've been running? Turns out they've been fine-tuning the connection between your brain and body, programming them to work together more efficiently. (Find out what's happening mile by mile in Your Brain On: Long Runs.)

Even more interesting, the muscle fibers in the weight lifters reacted much the same way as those of non-exercisers and both these groups were more likely to fatigue sooner.

While the researchers wouldn't go so far as to say one type of exercise was better than the other, it may be evidence that humans are natural born runners, said Trent Herda, Ph.D., an assistant professor of health, sport and exercise sciences and co-author of the paper. He explained that it appears the neuromuscular system is more naturally inclined to adapt to aerobic exercise than resistance training. And while the research didn't answer why or how this adaptation happens, he said these are questions they plan to address in future studies.

But while scientists are still sorting out all the differences between nature and nurture, it doesn't mean you should stop weight lifting. Resistance training has many proven health benefits (like these 8 Reasons Why You Should Lift Heavier Weights for starters). Just make sure you're getting your running in too as it appears each type of training helps our bodies in different ways.