Slow movement patterns are inefficient in terms of the time taken to complete a given activity; they are also physiologically inefficient and therefore associated with higher levels of fatigue. Essentially, the energy cost required to complete a standardized physical task will be relatively high for patients with pain compared to their age and gender-matched cohort because of slow inefficient movement patterns (Lee et al. 2002, 2007). For example, in a group of 50 patients with back pain in primary care, when compared to an age- and gender-matched cohort, it was found that the patients not only had a mean compromise in walking performance of approximately 20 % but also had a 20 % higher level of effort associated with the performance of that task (Lee et al. 2002). For patients with pain and illness (n = 100 patients with pain and HIV), walking task performance was compromised by 50 % (Simmonds et al. 2005). The high level of perceived effort and physiological inefficiency during task performance may be partially explained by the relatively greater magnitude and duration of all muscle activity during any task performance in people with pain. Figure 11.3 shows the relatively high magnitude and duration of muscle activity throughout the gait cycle in individuals with back pain and/or leg pain, compared to a pain-free cohort. This overall “stiffening effect” compromises movement efficiencies and is relatively fatiguing. Moreover, for individuals with pain, because movement is slower and task performance takes longer, this relatively high and fatiguing level of muscle activity persists for a relatively longer period of time.

The presence of depression as well as pain compounds the magnitude of psychomotor slowing. In a group of 24 individuals with chronic pain and depression (as measured by scores greater than 5 on the Patient Health Questionnaire) (PHQ9), a 60 % compromise in walking performance was found. The subjects in this study had a mean age of 54 years but had a mean movement speed equivalent to that of an 80–89-year-old person (Simmonds and Turner 2014). Clearly patients with pain and especially those with illness or depression have major mobility burdens that are incredibly fatiguing.

In an effort to improve movement without increasing pain or effort, we conducted a series of experiments to test the use of interval “sprint training,” music, and also different visual and audio cues in a virtual reality environment (Wilson et al. 2008; Song et al. 2011; Wang et al. 2013; Prasanna et al. 2010, 2013; Powell and Simmonds 2014; Simmonds and Zikos 2014). The details of the experiments have been reported elsewhere, but in essence, it was found that at the group level, “something” is generally better than “nothing,” that is, control condition to improve physical performance and specifically movement speed, but there is no evidence to support any single optimal approach. For example, in a repeated measure single-case series of individuals with fibromyalgia, the effectiveness of fast versus slow music versus no music on walking speed was tested and found that average gait speed was higher with fast music and lower with slow music, as compared to baseline (Prasanna et al. 2010, 2013). More importantly, the increase in performance was not matched with any increase in pain. This suggests that music could be a simple cost-effective intervention that translates easily to a clinical or lifestyle situation.

Within a virtual reality environment interfaced with a treadmill, audio cues (audible footsteps at slow, normal, and fast speeds) and visual cues (fast, slow, and no optic flow) were manipulated as individuals with musculoskeletal pain walked on an instrumented treadmill (Powell et al. 2006; Powell et al. 2010a, b). Essentially, both audio and visual cues led to individuals walking faster compared to baseline and a control (no cue) condition. Again, there was no increase in pain despite an increased level of activity. It has also been shown that in patients with fibromyalgia, computer game play can improve mood and also physical performance (Simmonds et al. 2012a, b; Simmonds and Zikos 2014).

Taken together, the results suggest that although patients with pain have generalized psychomotor slowing, speed of movement can be manipulated in a variety of simple ways without any aggravation of pain or symptoms. The mechanisms underlying this manipulation have not been specifically tested but could include focused attention to the stimuli with secondary distraction from pain since “busy” virtual reality screens appear to have a greater effect on reducing pain and increasing movement speed (unpublished data). Nevertheless, it remains to be seen whether the change in movement speed persists and faster movement speeds transfer to overground walking, during daily life, and maintained over the long term.

Accumulating evidence indicates that pain is associated with compromised cognition that includes reduced processing speed and mental flexibility as well as attentional and working memory deficits sufficient to impact daily activities (Wilson et al. 2008; Hart et al. 2000; Karp et al. 2006; Dick and Rashiq 2007; Abeare et al. 2010). The adverse impact of chronic pain on executive function may be due to the interruptive effect of pain and perceived pain-related threat on attentional processing (Dick and Rashiq 2007), but it is likely to be more complex than that and is probably linked to emotional state, as well as physical and social function. This problem of cognitive compromise in pain conditions adds to the therapeutic management challenge. Chronic pain, by its name and nature, is a chronic condition, and effective self-management is an ultimate goal. This often requires patients with pain to unlearn their misunderstandings about pain; self-regulate their thoughts, feelings, and behaviors; and learn new skills that enable effective self-management of chronic pain. Unlearning and relearning can be a challenge in ideal circumstances; unlearning and relearning in the context of unpleasant and distracting pain, emotional distress, and cognitive compromise adds to the challenge for patients and needs to be understood and taken into consideration by practitioners.

Numerous studies have demonstrated the benefits of physical exercise and activity for health promotion, disease prevention, disability management, and overall quality of life (Cepada and Carr 2006; Lønkvist et al. 2013; Burzynska et al. 2014; Bradt and Dileo 2014; Brocki et al. 2014; Klasnja et al. 2014). The mechanisms that underlie these effects are not completely clear and are most likely due to multiple physical, psychological, and social factors. To state the obvious, the beneficial effects of exercise or activity will only accrue if the exercise or activity is done and is maintained, hence the value of simple and enjoyable activities such as walking or dancing. Unfortunately and regardless of proven health benefits, many individuals have difficulty initiating and/or maintaining exercise programs or even assuming a more active lifestyle. Identifying perceived barriers to physical activity at an individual level is an essential component of physical therapy. The ten most common reasons for not engaging in physical activity are presented below (Centers for Disease Control (CDC) 2010). Noteworthy is that even at a general population level, fear of injury or reinjury is among the top ten barriers to physical activity. Among patients with pain, fear of injury will probably rank the highest, but other barriers will also play a role.

To date, a preponderance of evidence supports exercise and activity-based interventions for the improvement of physical, emotional, cognitive, and social function. Indeed the overriding gestalt from the exercise and activity literature suggests that no matter what variable is measured at baseline, it improves with exercise and/or activity. Activity is defined as any bodily movement produced by skeletal muscles that requires energy expenditure, whereas physical exercise is planned, structured, repetitive, and purposive in that improvement or maintenance of one or more physical fitness components is the goal (Caspersen et al. 1985).

There is also evidence to suggest that the nuances of exercise prescription are somewhat moot and that acute bouts of exercise versus chronic exercise, resistance exercise versus aerobic exercise, high intensity versus low intensity may be of less importance to impact long-term outcomes in a patient-centered approach to chronic pain than has been previously considered suggesting a primarily generalized and/or nonspecific effect of exercise/activity. This is an interesting contention that is in keeping with recent research supporting central and overlapping mechanisms that contribute to persistent pain states, for example, fibromyalgia, dysautonomia, chronic fatigue, and irritable bowel syndrome (Clauw and Ablin 2009).

Barriers to physical exercise and activity: “Just do it” is a reasonable tenet. However, the problem is how to best tailor guidance to physical activity interventions so that patients may overcome their barriers to exercise and activity. Initiation and adherence to continued movement and activity is important as initial improvements decline when exercise/activity is discontinued (Hooten et al. 2012; Häuser et al. 2010).

From a population standpoint, the Centers for Disease Control (http://​www.​cdc.​gov/​physicalactivity​/​everyone/​getactive/​barriers.​html) reports that the ten most common reasons why people do not engage in physical activity are as follows:

These reasons obviously apply to people with chronic pain and need to be considered and addressed within physical therapy while noting that individuals are likely to have unique circumstances that also need to be addressed. A patient-centered model focuses upon exercise/activities that are relevant to the patient and are enjoyable (Abdulla et al. 2013). This approach enhances the effectiveness of rehabilitation but more importantly promotes long-term adherence (Farrell et al. 2004). Where appropriate, clinicians should encourage early involvement of the entire family to increase physical activity, as this improves exercise adherence and non-activity-related family commitments are perceived as a barrier to physical activity http://​www.​cdc.​gov/​physicalactivity​/​everyone/​getactive/​barriers.​html.

With regard to exercise frequency, the recommended training effect dose is a minimum of 15 min for aerobic activity and a recommended “30 min most days or ≥5 days per week” (Garber et al. 2011). Though this recommendation is for healthy individuals, it was included in the American College of Sports Medicine consensus statement, and the recommendation probably applies to most individuals with chronic pain. The difference lies in the intensity of exercise that the individual can engage in based on their baseline level of physical condition. For example, deconditioned patients may need to engage in more frequent but short bouts of exercise/activity to accumulate a daily or weekly training effect. Likewise, the intensity of exercise/activity can be adjusted so that individuals work at a lower level of exertion but for a longer period of time.

A number of researchers have examined the relationships among measures as well as the predictive value of measures of mood, movement, and emotion across different patient groups. The findings show that the relationships are complex and enmeshed in both healthy pain-free individuals as well as those with chronic pain and chronic illness (Brunet et al. 2013). For example, Sabiston et al. (2008) examined the association between pain symptoms and affect and depression indicators of mental health among 145 breast cancer survivors over a 3-month period during which activity level was also monitored. Not surprisingly, they found that pain was negatively correlated with positive affect and physical activity and positively correlated with negative affect and depression. In addition, physical activity was positively correlated with positive affect and negatively correlated with depression. They also found that physical activity significantly mediated the relationship between pain and depression as well as between pain and positive affect (Sabiston et al. 2012, 2013).

In a series of clinical studies, the relationships among measures of physical performance, mood, and cognition were examined as well as the predictive value of physical performance on outcome (e.g., (Simmonds et al. 1998, 2005; Novy et al. 1999, 2002; Lee et al. 2001, 2003; Filho et al. 2002; Simmonds 2002, 2006, 2007; Shelton et al. 2009). Physical performance is measured with simple timed tests of function that include a timed 15 m fast walk and 5 sit-to-stand repetitions and a 6 min distance walk (6MDW). These tests have robust levels of reliability and strong validity (Simmonds et al. 1998, 2005; Lee et al. 2001; Novy et al. 2002; Simmonds 2002). The 6MDW was found to be the single best predictor of 5-year survival in patients with lymphoma, regardless of age or stage of disease. Moreover, in 47 patients with advanced non-small cell lung cancer, fatigue and the 6MWT distance were the strongest predictors of change in mental health-related quality of life, accounting for 13 and 9 % of the variance, respectively (unpublished data).

It is not surprising that the 6MDW is a good predictor of outcome and is negatively associated with depression and positively associated with social function. The ability to walk is fundamental to function, and the ability to walk a reasonable distance in a reasonable time enables one to potentially engage in social and recreational activities that are also associated with emotional health and well-being as well as improved cognitive function. The ability of simple quantitative measures of waking to predict outcome across a range of health conditions has led some to promote gait speed as the sixth vital sign.

In a recent meta-analysis, the effect of acute aerobic exercise on positive activated affect (PAA) was evaluated (Reed and Ones 2006). PAA included the affective component of well-being, energy, and positive activation. Key results showed that exercise was associated with increased PAA (d _corr = .47), while no exercise showed a negative association with PAA (d _corr = –.17). Moreover, within investigations of individuals with lower pre-exercise PAA scores, there were greater increases in PAA postexercise than with those that had mid and high PAA pre-exercise scores. Finally, this meta-analysis suggested that low-intensity exercise increases positive affect and that neither moderate nor higher intensity bouts of exercise have any significant additive effect.

Thus although exercise bouts of 20–30 min are recommended as a duration threshold for improved fitness levels (ASCM 2011; Berger and Motl 2000), conclusions from this meta-analysis show that shorter doses may suffice in improving affect, but the activity level must be maintained (Reed and Ones 2006). Notwithstanding the important contribution of physical fitness for overall physical health, level of fitness or change in fitness level is not necessary for activity to have beneficial effects on emotional state and cognitive function. For example, Loy et al. (2013) conducted a meta-analysis to identify parameters of exercise that promoted well-being. They found that a single bout of exercise (21–40 min of moderate intensity aerobic exercise) had a positive effect on affect (mean energy positive effect size change of .47 (95 % CI = .39–.56) but not surprisingly did not reduce perceived fatigue (mean effect size .03 (95 % CI = −.08–.13).

Several systematic reviews and meta-analyses have addressed the effect of exercise on depression. For example, a Cochrane Review by Cooney et al. (2013) evaluated 35 trials (1,356 participants) that compared exercise with no treatment or a control; the standardized mean difference for depression at the end of treatment was –.62 (95 % CI = −.08 to –.42), a moderate clinical effect. The authors further reported that there appeared to be little difference in effect between exercise therapies compared to pharmacological or psychological therapies. This suggests that individual treatment preferences should be considered by health-care providers but so also should the cost and the potentially negative consequences of specific treatments. For example, pharmacological therapies may have many more physiological and psychological consequences and little benefit other than on depressive symptoms. Exercise on the other hand can reduce depressive symptoms and has side effects that are positive in that they contribute to overall physiological, psychological, and social well-being.

Rethorst et al. (2009) conducted a meta-analysis of 58 trials (n = 2,982) on the effects of exercise on depression. The authors reported that exercise improved depression scores (0.8 SD units). There is also a suggestion that within a clinically depressed population, more frequent exercise (i.e., five times a week as opposed to two–four times a week) has a stronger treatment effect. There is also a suggestion of a U-shaped response to exercise bouts, that is, 30–40 min bouts of exercise appear optimum compared to shorter or longer exercise bouts. Whether optimal frequency and timing of exercise/activity that decreases depressive symptoms more effectively will contribute to better long-term adherence remains to be seen.

Adherence is a difficult issue that is not fully understood and often not managed well. However, there is evidence that shows at least for some patients a lifestyle approach to increasing physical activity may not only be beneficial but also adhered to (Stuifbergen et al. 2010). In a randomized trial of 84 participants with fibromyalgia that compared a fibromyalgia education program and a physical activity lifestyle program, the authors showed that the lifestyle physical activity program improved physical activity (daily activity counts increased by 54 %), reduced pain, and improved function (Fontaine et al. 2010).

Research on the effects of exercise on cognition and the mechanisms that underlie potential effects has burgeoned in recent years (Hötting and Röder 2013; Guiney et al. 2015; Law et al. 2011; Niemann et al. 2014). In a randomized trial by Hogan et al. (2013), an acute bout of moderate exercise, 15 min of stationary cycling, with healthy participants between the ages of 19 and 93 were compared with a control condition, and measures of cognitive function were included and compared across age ranges. The authors reported baseline differences on memory (b = −.28, p < .0001) and reaction time tests (.38, p = .001) as a factor of age but that exercise improved reaction time irrespective of age (b = .20, p = .014) but not accuracy of memory (b = −.09, p = .274).

Recent imaging research has contributed to major understandings of the brain and the mind under a variety of different conditions including pain, stress, illness, and aging. Although the implications are not clear and it is important not to over-interpret imaging findings, for example, it is known that chronic pain is associated with a reduction in gray matter in pain processing areas of the brain (Kuchinad et al. 2007) and that chronic aerobic exercise increases brain volume, at least in healthy elders (Colcombe et al. 2006). However, it must be emphasized that the mechanistic links between change in gray matter and pain, distress cognitive function, and exercise although seductive are also speculative at present.

Nevertheless, it is interesting that in a randomized controlled trial of elders (N = 59), ranging in age from 60 to 79 years, a 6-month aerobic training regimen compared to a low resistance and stretching intervention and control resulted in increased gray and white matter in the prefrontal and temporal cortices. By comparison, a control group of 20 younger, neurologically intact individuals (18–30 years) did not demonstrate any changes in brain volume. The reason for this is not clear, but it seems to reflect a limited capacity for change that may be age, pathology, or dose response related.

A meta-analysis by Colcombe and Kramer (2003) on exercise and cognition demonstrated that cognitive changes due to exercise primarily impacted executive function but the impact of exercise was moderated by the length and type of intervention as well as the duration of training sessions.

With regard to individuals with chronic pain and in one of the few studies that have measured cognitive function in patients with pain, a 4-week residential exercise program of 108 persons with chronic pain was administered that also included cognitive behavioral treatment. Ninety-five individuals were followed at 4 weeks and 9 months, and improvements were noted in physical and cognitive performance. Specifically, improvements at 4 weeks in physical performance (timed walk, repeated sit-to-stand, and stair climb) and cognitive performance (Stroop test) ranged between 40 and 100 %, and these improvements were maintained at follow-up (Wang et al. 2013).