Office of Aerospace Medicine Technical Reports
FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-81/2
Title and Subtitle: Cardiorespiratory assessment of 24-hour crash-diet effects on altitude, +Gz, and fatigue tolerances
Report Date: February 1981
Authors: Lategola MT, Lyne PJ, Burr MJ
Abstract: Eleven male surrogates of general aviation pilots, 25-40 years old, were tested for altitude, +Gz, and fatigue tolerances with and without previous fasting for 24 h. Testing included 2 min of lower body negative pressure (LBNP) at -40 torr (equivalent to +2Gz) after 118 min at 3,810 m chamber altitude and, after returning to ground level pressure, ergometry of 50 watts (W) for 6 min.
The fast had no statistically significant effect on altitude and fatigue tolerances. One subject, who tolerated 2 min of LBNP in the nonfasting condition, lost useful consciousness during this test in the fasting condition. Although the remaining 10 subjects tolerated 2 min of LBNP in both fasting and nonfasting conditions without statistically significant differences in quantitated parameters, 2 of them during fasting manifested symptoms usually associated with impending syncope. Pilots should be informed that a 24-h fast may reduce the margin for safe tolerance of or = +2Gz flight maneuvers.
Key Words: General aviation pilots, Crash diet, Cardiorespiratory assessment, Altitude tolerance, +Gz tolerance, Fatigue tolerance
No. of Pages: 20
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-81/2
Title and Subtitle: Cardiorespiratory assessment of 24-hour crash-diet effects on altitude, +Gz, and fatigue tolerances
Report Date: February 1981
Authors: Lategola MT, Lyne PJ, Burr MJ
Abstract: Eleven male surrogates of general aviation pilots, 25-40 years old, were tested for altitude, +Gz, and fatigue tolerances with and without previous fasting for 24 h. Testing included 2 min of lower body negative pressure (LBNP) at -40 torr (equivalent to +2Gz) after 118 min at 3,810 m chamber altitude and, after returning to ground level pressure, ergometry of 50 watts (W) for 6 min.
The fast had no statistically significant effect on altitude and fatigue tolerances. One subject, who tolerated 2 min of LBNP in the nonfasting condition, lost useful consciousness during this test in the fasting condition. Although the remaining 10 subjects tolerated 2 min of LBNP in both fasting and nonfasting conditions without statistically significant differences in quantitated parameters, 2 of them during fasting manifested symptoms usually associated with impending syncope. Pilots should be informed that a 24-h fast may reduce the margin for safe tolerance of or = +2Gz flight maneuvers.
Key Words: General aviation pilots, Crash diet, Cardiorespiratory assessment, Altitude tolerance, +Gz tolerance, Fatigue tolerance
No. of Pages: 20
Last updated: Friday, June 1, 2012