Documented experiences of the second wind go back no less than a hundred years, when it was taken to be a generally held reality of exercise. Regardless of whether or not the patient experiences symptoms of muscle ache, muscle fatigue, or cramping, the phenomenon of second wind having been achieved is demonstrable by the signal of an increased heart charge dropping while sustaining the identical pace on the treadmill. Inactive patients experienced second wind, demonstrated by relief of typical symptoms and the sign of an elevated heart price dropping, while performing low-moderate aerobic exercise (walking or brisk strolling). For the often active patients, it took more strenuous exercise (very brisk strolling/jogging or bicycling) for them to expertise both the everyday symptoms and relief thereof, along with the sign of an increased coronary heart price dropping, demonstrating second wind. As such, schopnost.cz those with muscle glycogenoses do not have to do prolonged exercise to expertise "hitting the wall". In experienced 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 grow to be the predominant supply of energy.

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