Author(s): HUANG, H.M., FU, S., TANG, C., YU, J., SHIH, Y., Institution: UNIVERSITY OF TAIPEI, Country: TAIWAN, Abstract-ID: 1713

INTRODUCTION:
Chemical Corps personnel wear nuclear, biological, and chemical protective clothing (NBC-PC) for mission operations, increasing metabolic rates and fatigue risk (1,2). Monitoring their physical strain non-invasively aids command in strategizing. The purpose of this study is to develop an estimated model to monitor workload.
METHODS:
Ten Chemical Corps personnel (male: n = 5, age = 23.6 ± 1.7 years; female: n = 5, age = 24.7 ± 3.9 years) were recruited for a study involving body composition analysis, micro-environment temperature (MT) and humidity (MH), and metabolic equivalents (METs) analysis by using the COSMED K5 wearable metabolic system. They underwent walking tests at 4, 6, and 8 km/h speeds, carrying loads of 0 kg, 10 kg, and 20 kg at ambient conditions 25°c. The statistical method used simple and multiple linear regression analysis to construct the most optimal estimated model with the highest correlation with METs.
RESULTS:
Simple regression analysis showed heart rate (HR) reserve ratio (HRRratio: HRactivity−HRresting/HRmax−HRresting) had the highest coefficient of determination for METs (R2 = 0.569, p < 0.001). The estimated model was ［METs ＝ 3.82＋7.70×HRRratio］. Multiple regression analysis showed the combination of HR, HRRratio, and MH had the highest coefficient of determination for METs (R2 = 0.717, p < 0.001). The estimated model was［METs = -15.479＋0.261×HR＋17.929×HRRratio−0.045×MH]
CONCLUSION:
The combination of multiple physiological parameters HR, HRRratio, and MH showed a high coefficient of determination for METs estimation. The METs increased by 2.4% to 20.9% when subjects performed activities in NBC-PC compared to standard uniforms (3). Aerobic capacity may be impaired at ambient temperature 35-35.5°C (4). Wearing NBC-PC results in an increase of 5.6°C for light work and 11.2°C for moderate to heavy work (5). The environmental temperature has a significant impact on the workload of individuals wearing NBC-PC. Therefore, this estimated model was only applicable at 25°C. Further research is required for extreme high and low temperature environments to develop specific estimated models.

References:
1. Young et al., Aviation, Space and Environmental Medicine, 2000
2. Gómez-Oliva et al., Physiol Behav., 2019
3. Dorman and Havenith, Eur J Appl Physiol., 2009
4. Cuddy, et al., J Therm Biol., 2014
5. McLellan, et al., Compr Physiol., 2013