Reference standards for power at the lactate threshold 2 for cycle ergometry throughout the lifespan in Germany

Cardiovascular fitness is an important health marker but reference values for the performance at lactate thresholds are lacking. This study aimed to provide reference standards for the performance on the cycle ergometer at fixed and individual lactate threshold 2 concepts throughout the lifespan. Data from two nationwide studies in Germany (KiGGS wave 2 and DEGS1 study) were pooled to a final sample of 2389 female and 2801 male participants aged 14-64. The data includes the results of an incremental bicycle ergometer test for the parameters absolute (W) and relative (W/kg) power at a fixed (3 mmol/l, LT_2fix) and at an individual lactate threshold 2 (base lactate + 1 mmol/l, LT_2ind). Generalized additive models for location, scale, and shape (GAMLSS) were used to calculate the reference values. The LT_2ind was reached at lower power than the LT_2fix. Throughout the lifespan, relative power had its peak at 14 years, declined until age 20 and then declined further but slower until the maximum age of 64 years. Absolute power remained fairly stable until age 45 after which it slowly declined until maximum age. The presented reference values can be used for estimating cardiorespiratory fitness among adolescents and adults in Germany.