Why Kids Always Have Energy: Their Muscles Recover In The Same Way As Endurance Athletes

Are you surprised? Thought not.

Ever wondered why kids run around all day and never seem to get tired? You’re probably not surprised to hear that a new study has found kids basically have the same energy levels as endurance athletes (so that’s why it’s virtually impossible to keep up!). 

Researchers discovered young children are able to run around all day because their muscles resist fatigue and recover in the same way as elite endurance athletes. The study, published in Frontiers in Physiology, asked young boys, untrained men and endurance athletes to do high intensity exercise and looked at how quickly they grew tired. 

“We found the children used more of their aerobic metabolism and were therefore less tired during the high-intensity physical activities,” said Sebastien Ratel, associate professor in exercise physiology who completed this study at the Université Clermont Auvergne. “They also recovered very quickly - even faster than the well-trained adult endurance athletes - as demonstrated by their faster heart-rate recovery and ability to remove blood lactate.” 

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Javier Pascual / EyeEm via Getty Images
Kids recovered more quickly than endurance athletes during the high intensity task.

Professor Ratel added: “This may explain why children seem to have the ability to play and play and play, long after adults have become tired.”

In the study, researchers compared the energy levels of 12 boys aged between eight to 12, 12 untrained men and 13 male endurance athletes. They were asked initially to do two, seven-second sprints, followed by one minute recovery. Next, they were asked to cycle as fast as they could for 30 seconds. 

Each group was assessed for the body’s two different ways of producing energy; 1) Aerobic - uses oxygen from the blood - and 2) Anaerobic - doesn’t use oxygen and produces acidosis and lactate which may cause muscle fatigue. The participants’ heart-rate, oxygen levels and lactate-removal rates were checked after the cycling tasks to see how quickly they recovered.

In all tests, the children outperformed the untrained adults. In recovery, they outperformed the endurance athletes. During the cycle, the adult’s power fell by 51.8%, and athletes by 41.8%, but children’s only decreased by 35.2%. 

Professor of health science at the University of South Australia, Tim Olds, said the study was interesting, but said it didn’t mean kids were, in general, as fit as endurance athletes. “What it’s found is the way they recover more resembles endurance athletes, than untrained adults,” he said, according to ABC News

Before You Go

Six People Over 80 Giving Us Serious Fitness Goals
Sister Madonna Buder, 86(01 of06)
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Sister Madonna Buder has earned the nickname ‘The Iron Nun’ having completed more than 40 Ironman races in the past 30 years.

She completed her first Ironman race - comprising of a 2.4-mile swim, 112-mile bike and 26.2-mile run - in 1985, aged 65.

At 75, she became the oldest woman to ever complete an Ironman triathlon and at 82, she set a world record as the oldest Ironman triathlon competitor.

She says faith, listening to her body and maintaining a positive attitude to her physical endurance have enabled her to succeed.
(credit:Nike)
Diana Green, 82(02 of06)
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Not only did Diana Green survive breast cancer, but on her 82nd birthday she ran the 2016 London Marathon to raise money for cancer research.

Speaking to HuffPost UK before the race she said: “The crowds are so wonderful, they really spur you on. I’m excited to be starting in the VIP section and spying some celebs!”

What a hero.
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Robert Marchand, 105(03 of06)
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French cyclist Robert Marchand, aged 105, recently set a world record on his bike covering 14.08 miles in one hour.

Afterwards he said he would've beaten his time if he hadn't missed a sign telling him he had 10 minutes left to cycle.

"Otherwise I would have gone faster, I would have posted a better time," he told Associated Press. "I'm not tired."
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Jean Dawson, 100(04 of06)
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At 100 years old, Jean Dawson is still a picture of health thanks to over 30 years of dedication to yoga.

She has been bending and twisting her body almost every single week for the past three decades.

“I really enjoy doing yoga," she said. "It has really changed my life and has helped cure aches and pains.

"I use to have trouble from a slipped disc in my back but doing yoga really helped me cope with it.”
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Ella Mae Colbert, 100(05 of06)
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In May 2016, Ella Mae Colbert set a new world record for the 100-meter dash, just one week after her 100th birthday.

Colbert has been running track since her school days and despite falling on her first attempt, she smashed the previous record for 100-year-old runners (which was 1 minute 17 seconds) and crossed the finish line in 46.791 seconds.
(credit:YouTube / Go Upstate)
Charles Eugster, 97(06 of06)
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Dr Charles Eugster is a bodybuilder and sprinter who has set numerous world records in his age group for races ranging from 60 meters to 400 meters.

The 97-year-old, who refers to retirement as "one of the worst things that you can do to yourself", said he got into fitness late on in life.

According to Today.com, he began serious weight training when he was 87 and didn't start running until he turned 95.

"By the time you get to 85 you may have lost about 50 percent of your muscle mass and power, so I think it's extremely important in your older age to do everything you can to build muscle," he added.
(credit:Harry Engels via Getty Images)