I get tired just watching a toddler play much less playing along with them. They're a ball of energy and that's literally true. A new study shows babies nine to fifteen months consume fifty percent more energy in a day than an adult. That's more than a pregnant woman or teen boys! It's so remarkable that scientists have said that in terms of burning energy, young children are like a different species.
In the study, researchers followed over six thousand people from multiple countries and included infants. They were given heavy water which means it contained non-radioactive "heavy" atoms of hydrogen and oxygen. These were measured in their urine, blood and saliva to see how fast energy was used on average a day.
What's neat is infants are born with similar metabolic rates as their moms but then ramps up rapidly. They need energy to grow their organs and the brain which burns more than forty percent of that energy. These rates stay high until children hit five years old and then slowly decline achieving a stable rate at age twenty.
That metabolism remains stable until age sixty then declines until they burn about twenty five percent less energy by the age of ninety. At that stage of life, people's organs shrink and the brain's gray matter is smaller.
Knowing this helps us understand our calorie needs and keeps us from hiding behind excuses that we're not capable of burning enough calories.
For more information…
Little kids burn so much energy, they're like a different species, study finds
In the most comprehensive analysis of its kind, scientists find stark differences between children and adults ...
Daily energy expenditure through the human life courses
Measurements of total and basal energy in a large cohort of subjects at ages spanning from before birth to old age document distinct changes that occur during a human lifetime. Pontzer et al. report that energy expenditure (adjusted for weight) in neonates was like that of adults but increased substantially in the first year of life (see the Perspective by Rhoads and Anderson). It then gradually declined until young individuals reached adult characteristics, which were maintained from age 20 to 60 years...