Physiological And Psychological Responses Associated With Running A 100-mile Ultramarathon Race.

Abstract

Ultramarathon races of 50 kilometers and longer are growing in popularity with over 400 such races scheduled in the United States in 2004. As the number of participants in such events grows, it is important to develop an understanding of the physiological and psychological demands associated with running in such an extreme endurance race. PURPOSE The purpose was to describe changes in selected physiological and psychological variables resulting from running a 100-mile ultramarathon race. METHODS Registered runners in the Mohican 100-mile Trail race were solicited for participation. Prior to the race, subjects completed a questionnaire that included their confidence for finishing the race (1–10 scale, 10=highest). Rating of perceived exertion (RPE) and blood glucose and lactate concentrations were taken at miles 20, 50, and 100. Measures taken before and immediately following the race included handgrip strength of the dominant hand and a mini mental status exam (MMSE). Data were analyzed using ANOVAs with repeated measures and are reported as means ± standard deviations. RESULTS Six women (age 37 ± 8y; 21% body fat) and 11 men (age 40 ± 8y; 13% body fat) who volunteered completed the race. Five volunteers did not finish. The prerace confidence scores of subjects who did not finish were lower than for those who completed the race (6.2 ± 2.5 vs. 9.2 ± 1.0; p ± 0.05). Finishing times for women ranged from 22:13:25 to 29:17:54 and for men 19:00:21 to 26:38:58. During the race, the men lost weight (pre, 73.1 ± 7.3; post, 68.7 ± 7.2 kg; p ± 0.05), but there was no change for the women (pre, 57.1 ± 5.6; post, 58.7 ± 5.0 kg). RPE increased between miles 20 and 50 and again between miles 50 and 100 (12.3 ± 2.0 to 14.1 ± 1.6 to 16.4 ± 2.9; both p ± 0.05). There were no changes in blood lactate or glucose concentrations. Grip strength declined in both women (pre, 29.9 ± 4.8; post 23.2 ± 3.5 kg; p ± 0.05) and men (pre, 47.0 ± 5.1; post, 40.4 ± 5.9 kg; p ≤ 0.05). There were no changes in MMSE, but three subjects reported hallucinations during the run. CONCLUSIONS Runners who finished the 100-mile race had higher prerace confidence levels than those who dropped out. Although men lost weight during the race, there was no weight change in the women in this study. Perceived exertion increased throughout the race, but there was no change in blood glucose or lactate concentrations. Grip strength declined in both men and women, possibly suggesting neural fatigue. Although no changes in mental status were observed, there were self-reported mental disturbances. Therefore, the MMSE should not be used alone in future studies to assess mental changes during an ultramarathon.