Among recreationally active adults, training methodology does not appear to modify orthostatic tolerance, though body composition and anthropometrics are related to orthostatic tolerance, highlighting the importance of maintaining lean mass regardless of training methodology.
Key Findings
Results
Orthostatic tolerance did not differ significantly between recreationally active, hybrid training, and endurance training groups.
Orthostatic tolerance was quantified via cumulative stress index (CSI) using a progressive lower-body negative pressure (LBNP) test.
CSI did not differ between groups (p = 0.2542).
Twenty-nine participants were classified into three groups: Recreationally Active (n = 10), Hybrid (n = 9), and Endurance (n = 10).
All participants reported at least 150 minutes per week of their respective training for ≥6 months.
The hypothesis that hybrid training would produce superior orthostatic tolerance compared to other groups was not supported.
Results
Fat-free mass (FFM) was positively related to cumulative stress index (CSI).
FFM was positively related to CSI with R² = 0.4092.
FFM differed significantly between groups (p = 0.0453): recreationally active 56.1 ± 10.0 kg, hybrid 65.5 ± 13.2 kg, endurance 51.2 ± 10.5 kg.
Body composition was assessed via air displacement plethysmography.
FFM data were missing for two participants in the normalized analysis.
Results
CSI normalized to fat-free mass did not differ between training groups.
CSI normalized to FFM did not differ between groups (p = 0.6210).
FFM was missing for two participants in this analysis.
This finding suggests that differences in orthostatic tolerance between groups are explained by differences in body composition rather than training methodology per se.
Results
The hybrid training group had significantly greater fat-free mass compared to the endurance and recreationally active groups.
Hybrid group FFM: 65.5 ± 13.2 kg.
Recreationally active group FFM: 56.1 ± 10.0 kg.
Endurance group FFM: 51.2 ± 10.5 kg.
Group difference was statistically significant (p = 0.0453).
Background
Previous studies suggest training methodology alters orthostatic tolerance in elite and/or well-trained athletes, but little is known about its effect in the general physically active population.
The study was designed to address this gap by examining recreationally active adults rather than elite athletes.
All participants reported at least 150 minutes per week of recreational activity for ≥6 months.
Hybrid training was defined as combined resistance and endurance training classes.
Hess H, Wheelock C, Hostler D. (2026). Orthostatic tolerance and training methodology in physically active men and women.. PloS one. https://doi.org/10.1371/journal.pone.0345175