Nasal breathing improves running speeds by 1-2%

The study followed 10 runners for six months and compared their maximum oxygen intake rates of nasal versus mouth breathing. “We have demonstrated the potential for a small performance improvement (through nasal breathing) by improving one’s physiological economy (or your ability to run faster while using less energy breathing),” says lead author George Dallam, Ph.D. professor in the School of Health Science and Human Movement at Colorado State University, and former inaugural national teams coach for USA triathlon, who has researched the effectiveness of nasal breathing.