Effort vs. exertion

Running hard feels hard because, well, it’s hard. But can we say anything more nuanced about the nature of this sensation? That was the aim of a group of Queen’s University researchers who travelled to Mount Everest Base Camp in Nepal, asking volunteers to perform a series of exercise tests at altitudes up to 4,370 m. They were investigating differences between exertion (the awareness of signals from body to brain, like temperature, muscle pain and levels of oxygen in the blood) and effort (the awareness of signals from brain to body as you force your muscles to keep contracting despite mounting fatigue). In the thin air of high altitude, the researchers speculated, our perceptions of exertion and effort might diverge.

This quest ion plays a cent ral role in debates about t he limits of endurance. Do we slow down because the pain and discomfort a re too intense, or because t he ef fort is too g reat ? Int uit ively, most of us would assume t he former – but t here’s mounting ev idence t hat it ’s ac t ually t he hard-to-a r t ic ulate concept of effort t hat matters most . The Queen’s team in Nepal didn’t end up f inding any link bet ween effort and oxygen levels in t he air, but it ’s a topic we’ ll hear more about as researchers cont inue to unt angle t he riddle of endurance.

Alex Hutchinson is one of the most respected sports science writers in the world. His latest book, Endure, is available now.