TY - JOUR

T1 - Loaded and unloaded marching

T2 - Implications for fluid replacement

AU - Dewhurst, Susan

AU - Bargh, Melissa J.

AU - Davidson, Chester

AU - Bampouras, Theodoros M.

PY - 2014/3/20

Y1 - 2014/3/20

N2 - Marching with essential survival equipment is a fundamental military exercise. A consequence of this increased load is an increased risk of dehydration. Dehydration may have fatal consequences in a combat situation where performance must be optimal. This risk can be minimized with an understanding of the additional fluid needs of soldiers marching when loaded compared to unloaded. The aim of this study was to quantify fluid loss caused by marching with a loaded Bergen rucksack and webbing of 33.5 kg for 45 minutes when compared to unloaded carriage in eight healthy male officer cadets (age, 20.5 ± 0.9 years; body mass 80.2 ± 9.2 kg). The findings demonstrate an increased rate of sweat loss (0.6 ± 0.2 L·h-1 to 1.2 ± 0.4 L·h-1; p<0.001) and increased average heart rate (105.5 ± 17.7 beats·min-1 to 136.6 ± 28.3 beats·min-1; p<0.001) for unloaded and loaded trial respectively. Urine osmolality significantly increased pre- to post-march (p<0.05), however there was no difference in this increase between the loaded and unloaded trial. The present study demonstrated that marching with a loaded rucksack and webbing increased sweat rate by 100% compared to the same march with no additional load. For soldiers to prevent dehydration and the potential detrimental effects on performance, fluid replacement should also be doubled when marching with loading in a temperate environment, however individual differences in sweat rate should be taken into account.

AB - Marching with essential survival equipment is a fundamental military exercise. A consequence of this increased load is an increased risk of dehydration. Dehydration may have fatal consequences in a combat situation where performance must be optimal. This risk can be minimized with an understanding of the additional fluid needs of soldiers marching when loaded compared to unloaded. The aim of this study was to quantify fluid loss caused by marching with a loaded Bergen rucksack and webbing of 33.5 kg for 45 minutes when compared to unloaded carriage in eight healthy male officer cadets (age, 20.5 ± 0.9 years; body mass 80.2 ± 9.2 kg). The findings demonstrate an increased rate of sweat loss (0.6 ± 0.2 L·h-1 to 1.2 ± 0.4 L·h-1; p<0.001) and increased average heart rate (105.5 ± 17.7 beats·min-1 to 136.6 ± 28.3 beats·min-1; p<0.001) for unloaded and loaded trial respectively. Urine osmolality significantly increased pre- to post-march (p<0.05), however there was no difference in this increase between the loaded and unloaded trial. The present study demonstrated that marching with a loaded rucksack and webbing increased sweat rate by 100% compared to the same march with no additional load. For soldiers to prevent dehydration and the potential detrimental effects on performance, fluid replacement should also be doubled when marching with loading in a temperate environment, however individual differences in sweat rate should be taken into account.

KW - Backpack

KW - Dehydration

KW - Hydration

KW - Military march

KW - Sweat

KW - Thermoregulation

KW - Urine osmolality

M3 - Journal article

AN - SCOPUS:84897872905

VL - 7

SP - 16

EP - 21

JO - Open Sports Sciences Journal

JF - Open Sports Sciences Journal

SN - 1875-399X

IS - SPEC.ISS1

ER -