title: The effects of acute hypoxia and exercise on marksmanship.
abstract: OBJECTIVE
  This study evaluated the effects of acute hypoxia and physical exertion on marksmanship.
  
  
  METHODS
  At each of five simulated altitudes (162 m, SL; 1015 m, 1K; 2146 m, 2K; 3085 m, 3 K; 3962 m, 4 K), subjects performed four shooting trials: at rest, immediately after a 60-s run with load, and twice more separated by 30-s rest. Arterial oxygen saturation (SaO2), HR, and ventilation rate (VR) were recorded.
  
  
  RESULTS
  Both increasing altitude and exercise significantly (P < 0.05) decreased marksmanship. The shooting scores at 4 K were significantly lower than those at all other altitudes. There was a likely trend for scores at 3 K to be lower than those at SL and 1K (P = 0.06 and 0.07, respectively). The shooting score at rest was significantly greater than that in all trials after exercise. Partial recovery of marksmanship after exercise occurred. Altitude and exercise both significantly reduced SaO2 and increased VR. HR did not change with altitude but increased after exercise. There was a strong positive correlation (r = 0.84) between marksmanship and SaO2. There was a strong inverse correlation (r = -0.72) between marksmanship and VR, and a modest inverse correlation (r = -0.54) between marksmanship and HR.
  
  
  CONCLUSIONS
  Increasing altitude impaired marksmanship, with a threshold at 3000-4000 m. The decreased marksmanship was closely related to decreased arterial oxygen saturation and increased ventilation, the latter increasing movement of the chest wall.
authors.affiliation: 1Department of Human Movement Sciences, Old Dominion University, Norfolk, VA; 2Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA; and 3School of Physical Therapy and Athletic Training, Old Dominion University, Norfolk, VA.
authors.forename: Chelsea M
authors.initials: CM
authors.lastname: Moore
authors.forename: David P
authors.initials: DP
authors.lastname: Swain
authors.forename: Stacie I
authors.initials: SI
authors.lastname: Ringleb
authors.forename: Steven
authors.initials: S
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000531:Altitude; D015444:Exercise / Q000502:physiology*; D005260:Female; D005389:Firearms; D006339:Heart Rate; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D012119:Respiration; D055815:Young Adult
chemical_list: D010100:Oxygen