Metabolic Changes Between Three Hydration Load Configurations

Abstract

Introduction: The need to investigate the impact of various types of Load Carriage (LC) in runners stems from the creation of wearable hydration pack systems configured to be worn on the back, waist, or carried in hands. Thus, the purpose of this study was to assess oxygen uptake (VO2), heart rate (HR), and respiratory exchange ratio (RER) potential differences between three LC hydration configurations in recreational runners.
Methods: Ten college students (5 males and 5 females) who were active runners (ages: 20.1±1.7) completed three trials of a self-paced 5K on a treadmill (incline 1%). The three treadmill conditions were a self-paced 5K, one without a wearable hydration system (control condition), one with a backpack hydration system, and one with a handheld hydration system. Weight of external LC conditions (backpack and handheld) was equal (1.3kg ≈ 3lbs).
Results: Results from the three repeated measures ANOVA tests indicated an overall difference in VO2 (F: 25.6, p < .001), RER (F: 76.9, p < .003), and HR (F: 21.7, p < .001) between the three trials. Post-hoc pairwise comparisons for VO2 (38±4.3 vs 35.5±4.6; p < .001) and RER (.89±.007 vs .86±.01; p < .002) determined subject differences between the handheld trial and the unloaded trial. Significant HR pairwise comparisons were between the unloaded and the handheld trials (165.1±5.5 vs 167.6± 5.4; p < .001) and between the backpack and handheld trials (165.4±5.1 vs 167.6± 5.4; p < .001).
Conclusions: Running with a backpack and/or handheld hydration system may alter metabolic responses versus running without. Choosing a backpack hydration configuration or lack thereof may be more favorable for recreational runners due to improved running economy.