This study investigated the relationship between leisure-time physical activity (LTPA) and circulating amino acids in girls at adolescence and early adulthood.
Isoleucine, leucine and tyrosine levels were significantly higher in individuals with lower LTPA compared to their peers at adolescence, independent of BMI. In a longitudinal setting, isoleucine and leucine levels increased significantly from adolescence to adulthood among individuals consistently low LTPA. Levels of circulating amino acids remained similar over time among individuals with consistently high LTPA. These results suggest subtle mechanistic link between isoleucine and leucine and high physical activity in childhood showing beneficial effects on overall health later in life.