Analysis of weight change and Borg rating of perceived exertion as measurements of runner health and safety during a 6-day, multistage, remote ultramarathon.

Objective: To determine the feasibility of using weight change and Borg score as tools for monitoring runner health and safety during a multistage, remote ultramarathon.

Design: Observational cohort study of feasibility on nonblinded event participants.

Setting: Six-day, multistage, remote ultramarathon in Utah.

Participants: Twenty-seven athletes in the 2012 Desert R.A.T.S. (Race Across the Sand) ultramarathon.

Assessment Of Risk Factors: Participant weight, health conditions that limited race participation, such as fatigue or exhaustion, and Borg score were reviewed.

Main Outcome Measures: Inability to complete a stage of the race (Did Not Finish status) or development of a clinically significant health condition during the race. Potential prognostic risk factors, such as a high Borg score and weight loss, were analyzed.

Results: An overall decrease in weight was observed over the course of the event. Median percent weight changes were losses of 2.96% (day 1), 7.42% (day 2), 2.21% (day 4), and 3.35% (day 6). There was no statistically significant difference in percent weight change between the 14 runners who finished the race and the 13 runners who did not finish the race (U = 73; z = 0.189; P = 0.85). Runners' ability to complete the race was related to the development of adverse health conditions (P = 0.004). Median Borg scores reported were 15 (day 1), 17 (day 2), 13 (day 3), 16 (day 4), and 15 (day 6). Only 2 racers who finished the entire event without adverse events ever gave a Borg score of ≥ 18.

Conclusions: The feasibility of weight change as a tool for monitoring runner health and safety in this setting is limited, but the Borg rating of perceived exertion warrants further study as a potential field expedient tool for monitoring runner health and safety during a multiday, remote ultramarathon.