"runners were expending about two and a half times their resting metabolic rate each day, a notable decline from the early days of the event, when they were burning at least three and a half times their resting rate"<p>Not sure why they call the findings surprising. Body builders have known that since before Schwarzenegger.<p>Body adapts and then you have to change the routine.<p>For long distance runners HIIT or just short, intense workout would be the obvious answer to up the metabolism again.
The validity of “doubly-labeled water” results is dubious at best in an organism with so many pathways to feed the citric acid cycle. Specifically I’m referring to fat adaptation and protein catabolism. Also, how does 600*(3.5-2.5)=6200/3.5?
Is this not simply explained by the body becoming more econonmical at repeating the same action over time?<p>After 6 weeks of daily running the body will adapt to be more effcient at running, so won't need so much energy to perform the same activity.
Nothing counterintuitive about these results. Anyone who has ever exercised knows that he has to switch things up if he intends to keep breaking the plateau either for strength or weight loss.<p>Our body is incredibly good at conserving energy which is why we feel less tired running 5kms daily after a while.<p>Only interesting point is the barrier on how quickly we can reach this efficiency with the limitation of how much fuel we can consume.