Pain Perception After Running a 100-Mile Ultramarathon

Abstract 

Hoffman MD, Lee J, Zhao H, Tsodikov A. Pain perception after running a 100-mile ultramarathon.

Objective

To determine if pain perception is affected by an extreme bout of exercise that causes ongoing exercise-related pain.

Design

Repeated-measures design.

Setting

Pre-race registration area and finish area of an endurance race.

Participants

Twenty-one competitors in the 2005 Western States 100 Mile Endurance Run and 11 control subjects who were assisting at the race but not running.

Interventions

Not applicable.

Main Outcome Measures

Overall pain and pain ratings on a pressure pain test before and after the event.

Results

Mean overall pain ± standard deviation on a 100-mm scale increased (P<.05) from 3±6mm before the run to 39±28mm after the run among the runners. The faster runners showed a mean reduction (P<.05) in pain ratings after the race of 15±20mm (on a 100-mm scale), whereas there was no change for the slower runners and controls. Findings were confirmed by model-based analysis.

Conclusions

The faster runners in a 100-mile (161-km) running race experience a modest temporary reduction in pressure pain perception that does not appear to be augmented by ongoing pain related to the exercise. The lack of a reduction in pain perception among the slower runners may be because an extreme bout of exercise of this nature can “exhaust” the systems responsible for exercise-induced analgesia in all but the most well-trained of runners, or that these systems were not activated because the slower runners were unable to maintain a high enough exercise intensity during the later stages of the race.

Key Words: Analgesia, Exercise, Pain, Pain threshold, Physical effort, Rehabilitation