Interaction of chemical defense clothing and high terrestrial altitudes on lift/carry and marksmanship performance.
BACKGROUND
The increased metabolic energy requirement imposed by a chemical defense uniform (CDU) and the lower maximal aerobic capacity associated with increased altitude should produce greater demands on the cardiopulmonary system during the performance of a given work task at increasing altitudes. We hypothesized that: a) relative to sea level, the decrements in physical work performance caused by ascending to high terrestrial altitudes would be greater in a CDU compared with a standard fatigue uniform (U.S. Army, BDU); b) the aversive subjective reactions to the CDU would be accentuated with increasing altitude; and c) that staging at moderate altitude, to induce acclimatization, would restore work performance at higher altitudes to sea level norms.


METHODS
The physiological and subjective responses of 8 male soldiers to work (10-min lift-and-carry task and rifle marksmanship) were measured. Subjects wore the BDU and a CDU ensemble (U.S. Army, BDO) at sea level, intermediate (2743 m) and high (4,300 m) altitudes following rapid and staged (3 d at 1,830 m) ascents to the higher altitudes.


RESULTS
Lift/carry task performance tended to be lower (p = 0.076) in the CDU vs. the BDU at altitude. The cardiopulmonary responses to the lift/carry task increased at altitude and were greater in the CDU. The subjects' perception of their ability to perform the lift/carry task at altitude was adversely impacted more in the CDU than the BDU. Rapid ascent to intermediate altitude degraded marksmanship in both uniforms. Following staged ascent, lift/carry task and marksmanship performance was restored to sea level norms.


CONCLUSIONS
Personnel wearing CDU or equivalent protective clothing at intermediate to high terrestrial elevations should anticipate proportionally larger CDU-induced decrements of work performance and lower tolerance to working in a CDU than experienced near sea level. Staging at moderate altitude is an effective strategy for restoring work performance to sea level norms at higher altitudes.
Muza
S R
SR
US Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA. smuza@natick-ccmail.army.mil
Jackson
R
R
Rock
P B
PB
Roach
J
J
Lyons
T
T
Cymerman
A
A
D000203:Activities of Daily Living; D000328:Adult; D000531:Altitude; D002618:Chemical Warfare / Q000517:prevention & control; D004734:Energy Metabolism; D017079:Exercise Tolerance; D005389:Firearms; D006801:Humans; D017770:Lifting; D008297:Male; D008887:Military Medicine; D008889:Military Personnel / Q000523:psychology; D011481:Protective Clothing / Q000009:adverse effects*; D012129:Respiratory Function Tests; D011795:Surveys and Questionnaires; D014481:United States; D014938:Work Capacity Evaluation