Clinical Predictors Of Vo 2 Max Response To Endurance Training: Heritage Family Study

BACKGROUND There is wide variation in the response of VO2max to exercise training. However, the influence of baseline phenotypes on VO2max trainability (ΔVO2max) is not well studied. Thus, the purpose of this study was to examine the contribution of modifiable, biologically, and clinically relevant baseline traits to absolute ΔVO2max (mL/min). METHODS: Participants were 488 sedentary, healthy adults between the ages of 17-65 (56% female, 33% Black) who completed 20 weeks of standardized aerobic exercise training as part of the HERITAGE Family Study. Phenotypes were measured at baseline and post-training. Baseline resting and submaximal exercise (i.e., 50 Watts) measures of cardiopulmonary (e.g., cardiac output, ventilation, blood pressure) and metabolic traits (e.g., lactate, free fatty acids), as well as body composition traits (e.g., percent body fat, fat free mass) were entered into a forward selection regression model predicting ΔVO2max with age, sex, and race forced into the model. RESULTS: A total of 34 traits were entered into the forward selection model, with 10 traits associated with ΔVO2max at p < 0.05: fat free mass (partial r2 = 2.9%); percent body fat (partial r2 = 1.7%); arteriovenous oxygen difference at 50 W (partial r2 = 1.6%); stroke index at 50 W (partial r2 = 1.5%); visceral fat (partial r2 = 1.5%); ventilation at 50 W (partial r2 = 1.0%); concentration of hemoglobin (partial r2 = 1.6%), hematocrit (partial r2 = 1.4%), and resting lactate (partial r2 = 0.6%); and tidal volume at 50 W (partial r2 = 0.7%). This panel of 10 traits explained approximately 14.5% of the variance in ΔVO2max. CONCLUSION: The contribution of baseline measures of modifiable cardiopulmonary, metabolic, and body composition traits to absolute ΔVO2max was minimal. The variance in ΔVO2max explained in this study may be higher than normal due to the use of predictor variables derived and tested in a single study cohort. There remains a large portion of the variance in ΔVO2max that is not yet explained. Further research is needed to identify other modifiable factors that may influence VO2max trainability.