Heart rate variability, task load and perceived exertion associated with a long-distance military ski exercise: A pilot study

Objectives: Skiing is practiced by the security forces posted at mountain areas for patrolling, securing borders, taking up rescue missions and sometimes as recreational activities. A study was planned to assess physiological mental stress of a military ski activity through measurement heart rate (HR) variability, task load perceived exertion. Materials Methods: Eleven healthy Indian soldiers, trained with skiing techniques, participated in 15 km 22 kg equipment predetermined snowy mountainous track. Pre- post-exercise HR variability (HRV) were recorded (bio-harness, Zephyr, USA) questionnaires, namely NASA index (NASA-TLX) Borg’s rating exertion (RPE) scale, filled after exercise. Time frequency domain parameters such HR, variations between successive RR intervals (RMSSD), standard deviation (SDNN) percentage value NN50 (pNN50), low- high-frequency bands (LF HF %) LF/HF ratio derived using Kubios software. Student’s t (paired) test applied compare pre- HRV Pearson’s correlation observe interdependencies subjective scores. Results: The findings depicted increase decrease overall (both significant). Besides this, there an LF (significant) (insignificant). Such response shows sympathetic dominance over parasympathetic autonomic nervous system. physical experienced during exercise also expressed high demand (79 out 100) (total score – 77 NASA-TLX moderately heavy RPE (14 20). Conclusion: differences variables ensured presence along Overall ratings. Carrying environment infested cold, wind chill, moderate hypoxia track possibly has induced observed participants. are important understand exact requirements warfare events carried forces.