Action research on the change of salty taste sensitivity during hiking Mt. Rokko

Abstract

The purpose of this study was to investigate the changes of salty taste sensitivity and sweat loss during hiking the mountain. Nine healthy young males（23±4 years）were volunteered to hike Mt. Rokko（altitude: 931 m）that located in Hyogo prefecture. Heart rate（HR）, rating of perceived exertion（RPE），body weight, water intake, sweat loss, and salty taste sensitivity（STS）were measured at 2 different altitudes of mountain ascending（P1: altitude 30 m, P2: altitude 920 m）.

HR in all subjects markedly increased during ascending. HRmax indicated 172±14 bpm. RPE at P1 was 7±1, and P2 was 15±3. It was considered that exercise intensity of hiking the mountain in this study was more than moderate intensity. Total water intake was 1,347±390 ml and total sweat loss were 2.2±0.9 kg in the subjects that drinking only the water condition. The percentage of total sweat loss to initial body weight indicated 3.4％. STS at P2 was significantly lower than those at P1（p＜0.05）.

This study clarified that drinking only the water during hiking significantly decreased salty taste sensitivity. These results suggest that the assessment of salty taste sensitivity might be the index for the prevention of heat stroke during hiking.