# The Influence of Training with an Evaluation Mask on Physiological Adaptations in a Recreational Athlete

## TL;DR

A five-week training program using a mask that simulates high altitude improved blood and body composition in recreational athletes, suggesting it could enhance endurance performance.

## Contribution

This study demonstrates that elevation training masks combined with HIIT can induce physiological adaptations in recreationally active men.

## Key findings

- Significant increases in erythrocyte count, hemoglobin concentration, and hematocrit were observed after the intervention.
- Body mass index and body fat percentage decreased significantly following the five-week training protocol.
- Peripheral oxygen saturation decreased progressively with increasing simulated altitude during training sessions.

## Abstract

Background: Innovative training strategies aimed at improving physiological efficiency are of growing interest in kinesiology and sports performance. Elevation training masks (ETMs) offer a practical means of inducing hypoxia-like stress. However, evidence of their effectiveness in recreationally active populations remains limited. This pilot study examined the efficiency of a five-week progressive ETM protocol combined with high-intensity interval training (HIIT) in eliciting physiological, hematological, and body-composition adaptations relevant to endurance performance. Methods: Nine recreationally active men completed a five-week intervention consisting of three treadmill-based sessions per week: one weekly incremental Conconi test and two structured aerobic–anaerobic HIIT sessions performed with an ETM. Mask resistance was progressively increased to simulate altitudes of approximately 900–3600 m. Hematological variables (erythrocytes, hemoglobin, hematocrit, erythrocyte indices, leukocytes, and platelets), body composition, maximal heart rate (HRmax), and peripheral oxygen saturation (SpO2) were assessed pre- and post intervention. Data were analyzed using paired-sample t-tests and repeated-measures ANOVA, with effect sizes reported (Cohen’s d, ω2). Results: A significant main effect of time on SpO2 was observed (F(1, 8) = 130.61, p < 0.001, ω2 = 0.69), along with a significant effect of training week (F(4, 32) = 17.41, p < 0.001, ω2 = 0.43), and a significant Time × Week interaction (F(4, 32) = 15.20, p < 0.001, ω2 = 0.42), indicating progressively greater post-exercise oxygen desaturation with increasing simulated altitude. Significant post-intervention increases were found in erythrocyte count, hemoglobin concentration, and hematocrit (p ≤ 0.009, d = 1.15–1.55), alongside increases in mean corpuscular volume and mean corpuscular hemoglobin. Platelet count increased significantly (p = 0.001, d = 1.68), while leukocyte values remained unchanged (p > 0.05). Body mass index (p = 0.049, d = 0.77) and body fat percentage (p = 0.012, d = 1.08) decreased following the intervention. HRmax tended to be lower at higher simulated altitudes. Conclusions: A five-week progressive ETM-HIIT protocol efficiently induced hematological and body-composition adaptations associated with improved oxygen transport and metabolic efficiency in recreationally active men. These findings support ETM-based training as an accessible strategy for enhancing physiological efficiency in endurance-oriented kinesiology practice, warranting confirmation in larger randomized controlled studies.