Effects of Exercise on Select Biomarkers and Associated Outcomes in Chronic Pain Conditions: Systematic Review.

ABSTRACT

BACKGROUND: Chronic pain is highly prevalent. Current management is challenged by lack of validated objective measures like biological markers. Clinical pain studies employing exercise interventions have evaluated biomarkers; however, it is unclear how exercise impacts biomarkers involved in pain pathways and whether these markers are associated with relevant pain-related outcomes. This systematic review evaluates data from clinical studies employing exercise interventions in chronic musculoskeletal nonmalignant pain conditions in which biomarkers in pain pathways were measured. METHOD: Published research studies from several databases were examined using the Jadad Scale for assessing the quality of clinical studies. RESULTS: Twelve research studies were reviewed. Jadad scores ranged from 5 to 11 out of 13 points. Inflammatory markers were most commonly measured followed by neurotransmitter-related genes and metabolite-detecting genes. After exercise interventions, changes in biomarkers involved in neurotransmission and inflammation suggest a hypoalgesic exercise effect. Significant biomarker associations were found with pain intensity, fatigue, depression, anxiety, and quality of life. However, there were varying methodologies in the studies reviewed. DISCUSSION: It remains a question whether biomarkers can be used as objective measures for risk assessment, diagnosis, or evaluation or as surrogate endpoints in chronic pain. Adequate sample sizes, optimal exercise dose determination, study replications, and longitudinal research studies with consistent methodologies are warranted. Regardless, the potential translational value of biomarkers in chronic pain is evident. Advancing nursing research in biomarkers is vital for moving the nursing discipline and clinical chronic pain practice forward. Developing a biobehavioral perspective in chronic pain is also necessary for comprehensive management.