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The study reveals that over 80% of teenagers and 28% of adults worldwide lack sufficient physical activity. It is defined as less than 150 minutes of moderate-intensity activity per week for adults and less than 420 minutes per week for children and adolescents. In post-industrial societies, the decline in activity during adolescence is often attributed to psychosocial environmental factors.
Researchers from the University of Colorado Anschutz Medical Campus tested the hypothesis that changes in adolescent activity levels are linked to energy requirements for growth and reproductive maturity. The findings were published in the Proceedings of the Royal Society B.
Study Overview
Researchers conducted an eight-month study on the indigenous people of Bolivia, the Tsimane. Their diet primarily consists of gathered and hunted foods. Tsimane individuals, overall, suffer significantly less from hypertension and cardiovascular diseases. Their level of physical activity is much higher compared to post-industrial societies.
Either way, older Tsimane adolescents become less active, similar to their peers in other cultures.
In Adolescence, We Experience Significant Energy Expenditure
The body grows rapidly, requiring a vast amount of energy for muscle, bone, neural, and the elements of sexual maturity. High levels of physical activity during this time, coupled with inadequate nutrition, delay sexual maturity. This is particularly noticeable among girls, as intense training is a proven risk factor for late menarche.
Adolescence is a life stage characterized by distinct endocrinological, anatomical and cognitive changes that likely require substantial energetic resources.
Ann E. Caldwell, PhD, study’s lead author, assistant professor of medicine specializing in endocrinology and metabolism at the University of Colorado School of Medicine
According to Caldwell, the striking similarity between Tsimane adolescents and their peers in post-industrial societies suggests that the increased energy needs during sexual maturation have a purely biological basis.
Scientists’ Conclusions
Dr. Caldwell and her colleagues believe that early intervention could help stay off the pubertal reduction in physical activity. However, they emphasize that the approach should be gender-specific, considering that girls generally mature earlier than boys.
Researchers also suggest that physical activity before adolescence lays the foundation for remaining active after puberty. According to them, efforts by the healthcare system will be more effective if directed towards increasing physical activity in childhood.
