Wonder why kids can play all day? They’re as fit as top athletes!

FOR parents worn out by chasing after their offspring all day it will come as little surprise.

But research shows that children have the same energy levels as endurance athletes, getting no more tired than distance runners and triathletes.

They even recover from exercise faster than sportsmen who have trained for months to reach their physical peak.

The study used a cycling challenge to compare the energy levels of boys aged eight to 12 against adults and endurance athletes. The youngsters proved better at using oxygen to fuel exercise, minimising fatigue. Sebastien Ratel, of the University of Clermont Auvergne, France, said: ‘Children might tire earlier than adults because they have limited cardiovascular capability, tend to adopt less-efficient movement patterns and need to take more steps to move a given distance.

‘Our research shows children have overcome some of these limitations through the development of fatigue-resistant muscles and the ability to recover very quickly from high-intensity exercise.’ The researchers recruited 13 nationallevel male competitors in triathlons, cycling and distance running. They were pitted against 12 boys and 12 men who did not regularly exercise intensively.

All three groups did two sevensecond sprints on an exercise bike followed by cycling as fast as they could for 30 seconds.

By measuring heart rates and lactic acid, the study showed children recovered from exercise faster than endurance athletes. Lactic acid is a by-product of exercise which causes muscle fatigue.

The results also showed children were less tired by the cycling than adults, and had the same fatigue levels as the athletes.

Children use more oxygen when exercising, perhaps because they are smaller so that their muscles are closer to the oxygen-rich blood being pumped from their heart. Their extra energy may come from a greater proportion of ‘slowtwitch’ muscles, which contract more slowly and may have evolved to protect children from hurting themselves by exercising too hard.

Dr Ratel, who carried out the research with Edith Cowan University in Perth, Australia, said: ‘We found the children used more of their aerobic metabolism and were therefore less tired during high-intensity activities. They also recovered very quickly – even faster than the well-trained adult athletes – as demonstrated by their faster heart-rate recovery and ability to remove blood lactate.

‘This may explain why children seem to have the ability to play and play and play, long after adults have become tired.’

In all tests for the study, published in the journal Frontiers in Physiology, children outperformed the adults who were not athletes.