Trends in physical fitness performance and body mass index of Swiss military conscripts, 2006-2024: a cross-sectional study.

Abstract

This study examined temporal trends in physical fitness performance, body mass index (BMI) and physical activity behaviour among Swiss military conscripts from 2006 to 2024, including male conscripts and female volunteers, and explored differences by age, language region and urbanicity. Cross-sectional analysis of nationwide conscription data between 2006 and 2024. Swiss Armed Forces conscription centres. Records from 706 994 individuals (99.1% male conscripts and 0.9% female volunteers) were analysed. After exclusions for implausible anthropometric values and incomplete or erroneous fitness data, 654 971 (92.6%) individuals were included in the BMI dataset and 558 224 (78.9%) in the fitness dataset. Self-reported physical activity was available for 552 205 individuals and waist circumference for 186 416. Primary outcomes were the Fitness Test for the Army (FTA) score and BMI. Secondary outcomes included individual FTA components, waist-to-height ratio (WHtR) and physical activity behaviour. In male conscripts, the adjusted mean FTA score declined from 74.2 (95% CI 73.9 to 74.4) in 2006 to 70.4 (95% CI 70.1 to 70.6) in 2024. Among female volunteers, FTA scores increased from 45.4 (95% CI 42.6 to 48.3) to 49.9 (95% CI 47.8 to 52.0). Mean BMI rose from 23.2 (95% CI 23.1 to 23.2) to 24.1 (95% CI 24.0 to 24.2) kg/m² in men and from 23.0 (95% CI 22.7 to 23.3) to 23.4 (95% CI 23.2 to 23.6) in women, with overweight prevalence increasing from 17% to 23% and obesity from 5% to 9%. The proportion classified as trained rose from 40% to 56% in men and from 50% to 64% in women. Physical fitness declined among male conscripts but improved among female volunteers, while BMI increased modestly in both sexes and WHtR remained stable. Despite these trends, self-reported physical activity increased substantially, indicating a mismatch between perceived activity and objectively measured fitness. These findings highlight the need for continued objective surveillance and targeted strategies to improve physical fitness in young adults.