both following treatment and at longer-term follow-up compared with a no-treatment control group (Mead et al., 2009), although, some methodological weaknesses were noted in the trials (e.g., inadequate blinding of outcome assessment). Evidence also exists that exercise may help relieve depressive symptoms of older adults who have osteoarthritis (OA) (Yohannes and Caton, 2010). The Arthritis Foundation and CDC, in their National Public Health Agenda for Osteoarthritis (2010), recommended promotion of low-impact aerobic and strength-building exercise for adults with OA in the hip and/or knee. OA research indicates that land-based exercise decreases pain, fatigue, and stiffness and improves performance on functional assessments (Callahan et al., 2008; Hughes et al., 2006). A Cochrane review of exercise for knee OA concluded that both land-based and aquatic exercise has short-term benefit in terms of reduced pain and improved physical functioning (Bartels et al., 2007; Fransen and McConnell, 2008).
Physical activity appears to be helpful to people with other chronic illnesses as well. For example, aerobic physical activity, alone or when included in multicomponent interventions, has also been shown to be beneficial to patients with fibromyalgia syndrome, having moderate-sized effects on pain, fatigue, depressed mood, and quality of life (Häuser et al., 2009, 2010). A Cochrane review on exercise for fibromyalgia indicated that moderate aerobic exercise may benefit overall well-being and physical function, whereas strength training appears more beneficial in terms of reducing pain, tender points, and depression (Busch et al., 2007). A limited number of studies have been conducted to test the effects of exercise on dementia. Results of the studies have been mixed, and the methodology has been of low to moderate quality, but some studies have indicated that participation in exercise is associated with such outcomes as better mobility and physical performance and improvement in activities of daily living (ADLs) (Blankevoort et al., 2010; Littbrand et al., 2011; Potter et al., 2011; Vreugdenhil et al., 2011); however, it is unclear whether exercise has an effect on cognitive functioning in this population (Littbrand et al., 2011).
Although substantial evidence has accrued for the benefits of physical activity for people with a range of chronic illnesses, there is limited evidence to indicate what type, duration, and intensity of exercise is most helpful for improving function, quality of life, and disease progression for most chronic illnesses, nor are there sufficient evidence-based programs to help individuals with chronic illnesses to successfully adopt and maintain exercise. A survey conducted of physical activity programs for the elderly in seven U.S. communities highlights the problems of both insufficient demands from this population as well as insufficient program capacity. The survey showed that the programs were serving only approximately 6 percent of the elderly population; however, less than 4 percent of the programs had waiting lists for their services (Hughes et al., 2005).