Alex Hutchinson
Your physical limits are shaped not just by your muscles and lungs, but by protective mechanisms in your brain that regulate how hard you can go.
Endurance is a psychobiological phenomenon where your subjective perception of effort ultimately dictates your decision to slow down or stop.
The brain can preemptively restrict muscle recruitment to hold energy in reserve, a protective measure that can make you feel closer to physical failure than your body actually is.
Environmental constraints like heat and oxygen deprivation can raise perceived effort and prompt the brain to moderate your pace, rather than acting as simple hard biological stops.