Experts weigh in on the popular claim that nasal breathing can improve exercise performance

Of all the things to worry about when working out - what exercise to do, how fast to go, how much to lift - breathing seems as if it should come near the bottom of the list.

- Hilary Achauer

NEW YORK - You do it automatically, so why complicate things?

To a certain extent, experts say, that approach is correct. As your exercise gets harder, your body naturally produces more carbon dioxide and you breathe faster to expel it and bring in as much oxygen as you need.

"Your body should more or less increase or decrease your breathing in relation to your effort and need," said Dr. Brian Kim, a professor at University of California, Irvine, and a team doctor for its athletic programme.

But research suggests that some breathing techniques - including diaphragmatic breathing - can help with performance during aerobic or high-intensity anaerobic activities and encourage recovery.

For other popular breathing strategies, like nasal breathing, there is little evidence that it can improve athletic performance.

The most important thing, experts said, is to avoid short, shallow breaths while exercising and make sure you are getting as much oxygen as possible. Beyond that, here is what fitness experts say about how the way you breathe can - or cannot - affect your workout.

BELLY BREATHING CAN HELP A LITTLE