Abstract
AIMS: This research examines fitness and body weight in two cohorts of adolescents, to determine continuity and changes in these measures across two generations.
METHODS: Height, weight and fitness were measured in a population-based cohort of 15 year-olds in 1986/7 (Dunedin Study, n=968). The same measures were obtained for their 15-16 year-old children between 2007 and 2015 (Next Generation Study, n=343). Fitness was defined as maximal aerobic capacity (V'O2max). Height and weight were measured in all participants and fitness was adjusted for weight (V'O2max/kg).
RESULTS: The Next Generation participants were, on average, heavier than the Dunedin Study participants had been, and had higher body mass index values (kg/m2). Unadjusted V'O2max values for boys did not differ between generations, but were lower in Next Generation girls compared to Dunedin Study girls. For both sexes, the Next Generation participants had lower weight-adjusted V'O2max values than the Dunedin Study participants. Compared to their parents, weight-adjusted V'O2max values were approximately 25% lower in girls and 15% lower in boys.
CONCLUSIONS: Overall adolescents today appear to be less fit and heavier than their parents were at the same age. The decline in fitness over a generation is particularly evident in adolescent girls, although boys also have lower levels of fitness once body weight has been taken into account.