Body mass index for athletes participating in swimming at the World Masters Games

Whilst there is growing evidence that physical activity across the lifespan is beneficial for improved health, there are many physiological changes involved with the aging process and subsequently the potential for reduced indices of health. The experimental aim was to gain improved understanding of the nexus between health, physical activity and aging by testing the hypothesis that prevalence of obesity (BMI ≥30 kg/m2) in the World Masters Games swimming cohort would be less than adult national populations.

Body mass index (BMI) of 527 (49.7% male, 50.3% female) World Masters Games (WMG) swimmers aged 25-91 yrs (mean 54.3, standard deviation ±12.2) was investigated using a survey tool.

Analysis demonstrated significantly (χ2=44.9, P<0.001) reduced obesity (9% vs. 21%) when compared to the adult (aged ≥18years) Australian as well as other appropriate national populations. Investigation revealed, amongst other findings, that in line with trends shown in the adult Australian population, WMG male swimmers had a significantly higher BMI (mean 25.9 vs. 24.6) than their female counterparts (Z=-5.8, P<0.001).

Evidence of improved classification in one index of health (BMI ≥30 kg/m2) for WMG swimmers raised the possibility of improved classification due to adherence to sport or that reduced BMI was advantageous, contributing to this cohort competing at the WMG. This proportionately under-investigated population having reduced obesity over national populations was of particular interest given the obesity epidemic, the multi-faceted approaches taken globally in an attempt to halt this epidemic and a usual tendency for increased incidence of obesity with age.