Role of Physical Activity in Managing Chronic Pain in Older Adults
The prevalence estimates of chronic pain among the elderly (>65 years) in the United States may be as high as 60% to 75%, with rates even higher for older adults in assisted living facilities or nursing homes.1,2 Epidemiological studies indicate that the prevalence of chronic pain increases with age up to the 7th decade of life and then plateaus or slightly declines.3 The most common types of pain in older adults include low back pain, joint osteoarthritis (eg, knee and shoulder), and peripheral neuropathic pain (often secondary to diabetes).4,5 Pain promotes physical disability,6,7 reduces quality of life,8 and is costly to both the individual experiencing pain and the nation.9
A recent study indicated that the national cost of pain exceeded the cost of the nation’s priority health conditions (eg, cardiovascular disease, neoplasms, endocrine, nutritional and metabolic diseases), with costs ranging from $560 billion to $635 billion annually.9 Alarmingly, more than half a billion people are currently over age 65 in the US, with this number expected to triple by 2050.10 As the number of older adults rises, frailty and chronic conditions associated with pain are likely to increase proportionally. Thus, primary care physicians (PCPs) can expect to encounter a considerable challenge in pain management with elderly patients. Given the burden of chronic pain in the elderly, possible preventive measures are both prudent and of the utmost importance.
Prescribe Physical Activity Preventively
Regular physical activity is a well-accepted approach for the management of chronic pain and is often recommended as an adjunct to pharmacotherapy. Physical activity also may play an important role in the prevention of persistent pain in older adults. Unfortunately, adults become more sedentary with advancing age, and consequently most older adults do not attain the minimum physical activity recommendations set forth by the American College of Sports Medicine (ACSM).11,12 This paper will provide a review of the current evidence for the role of physical activity in the prevention of persistent pain in the elderly as well as make a case for the role of physical activity in combatting 2 known and common risk factors—obesity and the decline of central pain modulatory processes—for chronic pain in older adults.
Current Evidence and Recommendations
While the experience of pain and physical activity appear connected bidirectionally, mounting evidence from prospective epidemiological studies suggests that a physically active lifestyle may reduce the risk of developing chronic pain in older adults.13-15 In a prospective cohort study of twins, the association between physical activity and incident low back pain (LBP), 1 of the most common forms of chronic pain in older adults in the elderly, was investigated.15 Being engaged in strenuous physical activity at baseline was strongly protective of developing LBP (either of shorter and longer duration)at the 2-year follow-up. Additionally, a relationship was found between increasing frequency of strenuous physical activity and the magnitude of the protective effect.15 Strenuous physical activity was defined as heavy gardening, long walks (>30 minutes) or bike rides, team sports, or dancing.15
A 14-year prospective longitudinal study investigated the impact of aerobic exercise on musculoskeletal pain in older adults who were Runners’ Association members and community controls.13 Runners had markedly reduced pain levels relative to controls, despite the fact that fractures were somewhat more prevalent among the runners. Additionally, exercise was associated with a substantial reduction in musculoskeletal pain even after controlling for sex, baseline body mass index (BMI), and attrition. These large prospective studies provide compelling evidence for the protective effect of regular moderate-intensity physical activity for low back pain and musculoskeletal pain in older adults.
While the direction of causality could not be inferred, several large cross-sectional epidemiological studies support the relationship between chronic pain and regular physical activity in older adults.14-16 Evidence from the Nord-Trondelag Health Study (HUNT 3), involving more than 46,000 participants, found a linear relationship between chronic pain and the frequency, duration, and intensity of recreational exercise for participants over 65 years.14 However, a U-shaped relationship between chronic pain and exercise frequency was discovered for individuals age 20 to 64 years in which inactivity and excessive activity were associated with chronic pain.15 The different chronic pain-exercise relationships found between age groups was attributed to a lower total amount of physical activity among older adults compared to middle-age and younger adults. In line with this theoretical U-shaped relationship between chronic low back pain and physical activity, Heneweer and colleagues revealed that the extremes of low and high physical activity levels were associated with an increased risk for chronic low back pain in middle-age and older adults.16 This U-shaped relationship was especially true for women but less so in men. Further evidence supports heavy physical workloads; frequent lifting, bending, and twisting; and extreme sport activities may raise the risk for low back pain.17-19 While physical activity may act as a preventive factor for chronic pain, excessive physical activity may raise the risk for pain in some chronic pain conditions (Figure 1).16
While several large epidemiological studies offer a strong association between a physically active lifestyle that reduces the risk for the development of chronic pain, direct evidence is still lacking. Therefore, characteristics of optimal physical activity programs for the prevention of chronic pain presently are not known. As such, until high-quality evidence becomes available, older adults should be encouraged to meet the ACSM’s physical activity recommendations for older adults for the purpose of pain prevention (Table 1).20