Effects of Level of Dietary Salt Restriction and Marching in a Simulated Desert Environment on Rifle Marksmanship
Abstract
Rifle marksmanship using the Weaponeer was assessed after walking (1. 56 m/sec, 5% grade, 30 min/hr, 8 hr/day, 10 d) in the heat (41 deg C, 20% RH). Participants (17 male soldiers) consumed a diet containing 4 g or 8 g NaCl per 24 hours throughout testing. The influences of repetitive heat-exercise exposures, NaCl level in the diet, and physiological responses to heat stress upon rifle shooting were examined. Marksmanship measures included hitting a pop- up target at simulated distances of 100 m and 250 m, and shooting at a stationary zeroing target at a 25-m simulated distance. Participants fired 32 shots at the pop-up targets and nine shots at the zeroing target. Marksmanship testing was done every other day for 10 days after completing eight hours of exercise in the heat. A significant drop in the percentage of 250-m pop-up targets hit occurred only after the first day of heat exposure (p<0.05). No differences occurred for the 100-m pop-up target, or the various 25-m stationary target measures. Plasma volume loss was significantly correlated (R=0.64, p<0. 01) with distance from the centroid of mass (DCM) for the group consuming the 8 g NaCl diet. The findings indicated that: (1) initial heat/exercise exposure elicited a decrement in shooting accuracy (250 m), (2) an insignificant but consistent trend favored the 8 g NaCl diet with respect to shooting performance, and (3) plasma volume losses were correlated with DCM for the 8 g NaCl dietary group.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA268588
Entities
People
- E. W. Askew
- Lawrence E. Armstrong
- Ralph P. Francesconi
- Roger W. Hubbard
- William J. Tharion