Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
‘Second wind’ describes the phenomenon where, after an initial period of breathlessness and difficulty early in sustained exercise, a runner suddenly feels more comfortable and able to continue with relative ease. It is thought to result from the body fully shifting to aerobic metabolism, optimal blood flow redistribution and the clearing of the initial oxygen deficit. The endorphin release sometimes called ‘runner’s high’ is a related but distinct phenomenon. Proper warm-up reduces the early discomfort that precedes the second wind.
- Return of ease after early difficulty
- Body shifts fully to aerobic metabolism
- Distinct from ‘runner’s high’ (endorphins)
- Warm-up reduces preceding discomfort
In practice
The 'second wind' phenomenon — a sudden easing of breathing difficulty and perceived effort during sustained exercise — is thought to result from the body stabilizing its oxygen delivery systems and adjusting breathing rhythm after an initial period of adjustment, though the exact physiological mechanisms remain an area of ongoing research rather than a single, fully settled explanation.
FAQ
What causes the 'second wind' feeling during exercise?
The exact mechanism isn't fully settled, but it's thought to involve the body's oxygen delivery and breathing rhythm stabilizing after an initial adjustment period, easing the perceived difficulty of sustained effort.
Does everyone experience a second wind during exercise?
Not universally or predictably — it's a commonly reported subjective experience, particularly during sustained aerobic efforts, but it isn't a guaranteed or precisely reproducible phenomenon for every athlete or every session.