Pain is a nebulous, subjective, multi-dimensional concept that can factor heavily into any injury. There are different types of pain- muscle soreness from exercise, tenderness from blunt trauma (perhaps given to you by your gracious physical therapist) or inflammatory pain indicating tissue damage. Strengthening is often emphasized in rehabilitation to support physically weak or faulty structures, ultimately to decrease pain. But how else might strengthening effect pain?
A recent study in Medicine and Science in Sports and Exercise looked at the relationship between endurance and perception of pain. Twenty four healthy women, with peak aerobic capacities indicating normal to moderate fitness levels, were divided into control and exercise groups. The exercise group completed eighteen training sessions over six weeks while the control group was instructed to live life as per usual. Pre and post measurements of pain threshold and pain tolerance were taken. Pain threshold was measured by systematic application of a blunt force measuring probe to four muscles (trapezius, biceps, rectus femoris, and tibilias anterior), the subject distinguishing when they considered the pressure to be painful. Pain tolerance was measured by ischemia, using a blood pressure cuff around the arm at 200mmHg of pressure while the subject performed a gripping exercise until they could no longer stand the pain.
The results revealed an increase in pain tolerance with increased aerobic capacity. After six weeks of training, the exercise group had increased their aerobic capacity by 15%, while no noticeable change was noted with that of the control group. Pain tolerance had improved for the majority of the exercise group (+20.3% for 10/12 participants) but not for the control (-3.7% for 5/12). No significant changes were noted in pain threshold for either group. Perhaps these results indicate more of a mental fitness in disregarding pain, as the physical ability to feel pain remain unchanged.
Though this study observed only a very small, specific sample with interesting measurements of fitness, pain tolerance, and pain threshold, there has previously been little to no research considering a relationship between endurance and pain tolerance. Regardless of how well these results translate to other populations, this study lends to a continued emphasis on strengthening in pain management. The mental requirements for cardiovascular improvement may be similar to one’s ability to deal with pain- namely via decreased attention to noxious stimuli. Acceptance of pain and continuing on in spite of it, however, takes a bit more finesse. Next on the agenda is then distinguishing between acceptable and unacceptable pain. Or consult your neighborhood-friendly physical therapist.
Resources
1. Jones MD, Booth J, Taylor JL, Barry BK. Aerobic training increases pain tolerance in healthy individuals. Med Sci Sports Exerc. 2014 Aug;46(8):1640-7. doi: 10.1249/MSS.0000000000000273. PubMed PMID: 24504426.