Hydration Status as a Predictor of High-altitude Mountaineering Performance

Abstract

Background: Hydration status is a controversial determinant of athletic performance. This relationship has not been examined with mountaineering performance.Methods: This was a prospective observational study of mountaineers who attempted to climb Denali in Alaska. Participants’ urine specific gravity (SG), and ultrasound measurements of the inferior vena cava size and collapsibility index (IVC-CI) were measured at rest prior to ascent. Upon descent, climbers reported maximum elevation gained for determination of summit success.Results: One hundred twenty-one participants enrolled in the study. Data were collected on 111 participants (92% response rate); of those, 105 (87%) had complete hydration data. Fifty-seven percent of study participants were found to be dehydrated by IVC-CI on ultrasound, and 55% by urine SG. No significant association was found with summit success and quantitative measurements of hydration: IVC-CI (50.4% +/- 15.6 vs. 52.9% +/- 15.4, p = 0.91), IVC size (0.96 cm +/- 0.3 vs. 0.99 cm +/- 0.3, p = 0.81), and average SG (1.02 +/- 0.008 vs. 1.02 +/- 0.008, p = 0.87). Categorical measurements of urine SG found 24% more successful summiters were hydrated at 14 Camp, but this was not found to be statistically significant (p = 0.56). Summit success was associated with greater water-carrying capacity on univariate analysis only: 2.3 L, 95% confidence interval (2.1 – 2.5) vs. 2.1 L, 95% confidence interval (2 – 2.2); p < 0.01.Conclusions: Intravascular dehydration was found in approximately half of technical high-altitude mountaineers. Hydration status was not significantly associated with summit success, but increased water-carrying capacity may be an easy and inexpensive educational intervention to improve performance.

Diet, Supplementation and Nutritional Habits of Climbers in High Mountain Conditions

“…Our results show that nearly half of the respondents drink 2-3 L of fluids per day in the mountains, while the rest of the respondents take in even smaller amounts of fluids per day (Figure 3), which can lead to dehydration and have a negative impact on acclimatization. A study by Ladd et al [24] based on two methods of measuring hydration status (urine specific gravity and ultrasound measurements of the inferior vena cava size and collapsibility index) found that about half of the surveyed climbers who had climbed Denali in Alaska were dehydrated. Water supply was monitored in a group of Italians and Nepalese during an expedition to the Himalayas, reaching 3099 ± 462 g/day and 3240 ± 310 g/day, respectively [28].…”

“…High-altitude hypoxia increases fluid loss and contributes to dehydration, which reduces aerobic capacity in high-altitude conditions [23]. Optimal hydration can be limited by environmental conditions, but also by the time and fuel resources needed to prepare drinking water, sourced from the glacier [24]. Reduced thirst at high altitudes is another factor contributing to dehydration [25].…”

The challenges of commercial mountaineering on the highest Volcanic Seven Summit, the Ojos del Salado

“…Extremely low humidity is a major health concern for climbers (Davies, E.D. et al 2016;Ladd, E. et al 2016) as -compounded by the high rate of respiration -it leads to the severe drying of the skin around the mouth and nose and the mucosal lining of the airways (Tsutsumi, H. et al 2007; Takada, S. and Matsushita, T. 2013). The dry mucosa of the larynx could produce a dry, hacking cough named high altitude bronchitis (Cogo, A. et al 2004;Ladd, E. et al 2016), and skin dryness could also lead to injuries of the epidermis.…”