Documented experiences of the second wind return no less than 100 years, when it was taken to be a commonly held fact of exercise. Regardless of whether the affected person experiences symptoms of muscle ache, muscle fatigue, or cramping, the phenomenon of second wind having been achieved is demonstrable by the sign of an increased coronary heart price dropping while sustaining the same speed on the treadmill. Inactive patients experienced second wind, demonstrated by relief of typical signs and the sign of an increased heart charge dropping, Mitolyn Official Site while performing low-moderate aerobic exercise (walking or brisk strolling). For the usually energetic patients, it took extra strenuous exercise (very brisk walking/jogging or bicycling) for them to experience each the everyday signs and relief thereof, along with the sign of an increased coronary heart fee dropping, demonstrating second wind. As such, those with muscle glycogenoses don't need to do extended exercise to experience "hitting the wall". In skilled athletes, "hitting the wall" is conventionally believed to be due to the physique's glycogen shops being depleted, with "second wind" occurring when fatty acids change into the predominant supply of energy.

The delay between "hitting the wall" and "second wind" occurring, has to do with the slow speed at which fatty acids sufficiently produce ATP (energy)