ENDOCRINE-METABOLIC RESPONSES TO PARACHUTING

This was a feasibility study in which the usefulness of urinalysis for the assessment of stress in parachutists was tested. Eight sport parachutists were studied, each collecting urine specimens on two separate occasions, with each specimen representing a 2-hour period which included ascent to altitude, the jump, and a postjump rest period. The urinary determinations included epinephrine, norepinephrine, 17-hydroxycorticosteroids, magnesium, potassium, sodium, phosphorus, urea, and creatinine. Creatinine served as the base to which the other eight constituents were referred. The individual urinary constituents, when expressed as percent of respective control values and averaged, gave a single value for the endocrine-metabolic response, the so- called stress index or score. Five of the jumpers were novices whose jumps were made at lower altitudes than were used by the remaining 3 jumpers who were highly experienced. Sympathoadrenomedullary stimulation of high degree was evident for all but one of the jumpers, but few of the jumpers showed evidence of adrenocortical stimulation or of metabolic hyperactivity. The stress score was 162% for the novice group, 225% for the experienced group, and 186% for the entire group. The latter value differed significantly from zero (P .001).