Researchers at Duke University appear to have found the limit to which extreme endurance athletes’ bodies can keep up the pace for so long before turning on itself.
The researchers primarily studied runners who were running the equivalent of 117 marathons over the course of several months, and found as time went on, the athletes’ bodies were less and less able to turn food calories into energy before eventually switching to fat-burning.
The researchers measured this by starting with an average person’s Basal Metabolic Rate – the number of calories burned during a day of rest – and judging how many calories from food an athlete’s body can convert into energy each day, over the course of many days of progressive exercise.
As expected, the athletes bodies’ started very efficiently, burning as many as 11 times as many calories as the BMR on day one. However, that number quickly decreased as the athletes started doing multiple days of intense exercise – as would be done in an ultra-marathon, or the Tour De France. Eventually, as athletes neared a year of such daily exercise, the most calories from food their bodies could burn was only 2.5 times the BMR – in other words, about 4,000 calories per day. After that, their bodies switched to consuming its own fat.
That 2.5 ratio is close to the maximum ratio a pregnant woman can burn before her body turns to fat burning – about 2.2 times the Basal Metabolic Rate.
According to a study recently published in the journal “Neuroimage,” light cardiovascular exercise like jogging can help retain newly-learned motor skills.
Researchers at McGill University in Canada found that 15 minutes of cardiovascular exercise immediately after practicing a new motor skill increased long-term retention of that skill, by increasing brain connectivity and efficiency. This research could have a big impact for athletes and stroke-sufferers if the findings are verified.