Effect of combat gear and body armor on ventilatory thresholds and muscle oxygenation during graded treadmill exercise in female and male soldiers
- 1Department of Medical Imaging and Physiology, Skåne University Hospital , ,
- 2Department of Clinical Sciences, Lund, Section of Rheumatology, Lund University , ,
- 3Department of Environmental and Biosciences, School of Business, Innovation and Sustainability, Halmstad University , ,
Abstract
Introduction: This study aimed to determine how combat gear and body armor (CB) affect the relationship between treadmill setting and internal physiological responses at ventilatory transitions, and to characterize right vastus lateralis muscle oxygen saturation (SmO2) and exploratory early reoxygenation in female and male soldiers.
Methods: Nine female and nine male soldiers completed randomized no-load (NL) and CB graded treadmill tests to volitional exhaustion. Heart rate and pulmonary gas exchange were measured, and right vastus lateralis SmO2 was assessed using near-infrared spectroscopy. VT1 was identified using the V-slope method and VT2 using ventilatory-equivalent criteria. SmO2 outcomes were referenced to a 30-s standing value.
Results: VT1 was identified at a lower treadmill stage in CB than in NL in men (5.2 ± 0.8 vs. 6.4 ± 1.7; p = 0.02) and women (5.1 ± 0.6 vs. 7.1 ± 1.5; p <0.01). Absolute V̇O2 at VT1 changed little, whereas HR was higher in CB in men (p <0.01) and women (p = 0.04). VT2 was also identified at a lower stage in CB in both groups (p <0.01). Baseline-referenced right vastus lateralis desaturation amplitude during CB was greater in men than women (39.0% ± 23.9% vs. 17.1 ± 14.5%; p <0.01), although adipose-tissue thickness at the sensor site was not measured. No statistically significant effects were detected for the early post-exercise indices.
Discussion: CB altered the treadmill setting at which ventilatory transitions were observed and increased cardiovascular demand at VT1 without essentially changing absolute V̇O2 at VT1. This indicates a changed relationship between treadmill task, transported mass, and internal physiological response rather than demonstrated displacement of the underlying metabolic threshold. The site-specific SmO2 and early reoxygenation findings were exploratory, and between-sex interpretation was limited by the small sample and unmeasured adipose-tissue thickness.
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BibTeX
@article{larsson2026effect,
title = {{Effect of combat gear and body armor on ventilatory thresholds and muscle oxygenation during graded treadmill exercise in female and male soldiers}},
author = {Jonas Larsson and Magnus Dencker and Ann Bremander and M. Charlotte Olsson},
journal = {Frontiers in physiology},
year = {2026},
month = oct,
doi = {10.3389/fphys.2026.1943048},
url = {https://europepmc.org/article/PMC/PMC13727441},
note = {CC BY},
}
RIS
TY - JOUR
TI - Effect of combat gear and body armor on ventilatory thresholds and muscle oxygenation during graded treadmill exercise in female and male soldiers
AU - Jonas Larsson
AU - Magnus Dencker
AU - Ann Bremander
AU - M. Charlotte Olsson
PY - 2026
DA - 2026/10/20
JO - Frontiers in physiology
DO - 10.3389/fphys.2026.1943048
UR - https://europepmc.org/article/PMC/PMC13727441
AB - Introduction: This study aimed to determine how combat gear and body armor (CB) affect the relationship between treadmill setting and internal physiological responses at ventilatory transitions, and to characterize right vastus lateralis muscle oxygen saturation (SmO2) and exploratory early reoxygenation in female and male soldiers. Methods: Nine female and nine male soldiers completed randomized no-load (NL) and CB graded treadmill tests to volitional exhaustion. Heart rate and pulmonary gas exchange were measured, and right vastus lateralis SmO2 was assessed using near-infrared spectroscopy. VT1 was identified using the V-slope method and VT2 using ventilatory-equivalent criteria. SmO2 outcomes were referenced to a 30-s standing value. Results: VT1 was identified at a lower treadmill stage in CB than in NL in men (5.2 ± 0.8 vs. 6.4 ± 1.7; p = 0.02) and women (5.1 ± 0.6 vs. 7.1 ± 1.5; p <0.01). Absolute V̇O2 at VT1 changed little, whereas HR was higher in CB in men (p <0.01) and women (p = 0.04). VT2 was also identified at a lower stage in CB in both groups (p <0.01). Baseline-referenced right vastus lateralis desaturation amplitude during CB was greater in men than women (39.0% ± 23.9% vs. 17.1 ± 14.5%; p <0.01), although adipose-tissue thickness at the sensor site was not measured. No statistically significant effects were detected for the early post-exercise indices. Discussion: CB altered the treadmill setting at which ventilatory transitions were observed and increased cardiovascular demand at VT1 without essentially changing absolute V̇O2 at VT1. This indicates a changed relationship between treadmill task, transported mass, and internal physiological response rather than demonstrated displacement of the underlying metabolic threshold. The site-specific SmO2 and early reoxygenation findings were exploratory, and between-sex interpretation was limited by the small sample and unmeasured adipose-tissue thickness.
SN - 1664-042X
ER -