What causes inspiratory muscles fatigue?
Muscles working hard in exercise need more oxygen, so more blood is pumped around the body, picking up more CO2 from the muscles, to be released in the lungs to be breathed out, and picking up more oxygen there to deliver to the muscles. When respiratory muscles demand for energy exceed supplies, the energy stored within the muscles is depleted and the force of contraction diminishes. Fatigue of the inspiratory muscles usually elicits an increase in minute ventilation and respiratory, and sometimes may result in a reduction rather than an increase in motor outflow to the respiratory muscles. The weakness experimented can be counteracted with a proper breathing training.
