Effect of Different Volumes of Interval Training and Continuous Exercise on Interleukin-22 in Adults with Metabolic Syndrome: A Randomized Trial

Manual therapy and exercise effects on inflammatory cytokines: a narrative overview

Background

Matching disease and treatment mechanisms is a goal of the Precision Medicine Initiative. Pro- and anti-inflammatory cytokines (e.g., Tumor Necrosis Factor-alpha, Transforming Growth Factor-beta, and Interleukin-2, 10, and 12) have gained a significant amount of interest in their potential role in persistent pain for musculoskeletal (MSK) conditions. Manual therapy (MT) and exercise are two guideline-recommended approaches for treating MSK conditions. The objective of this narrative overview was to investigate of the effects of MT and exercise on pro- and anti-inflammatory cytokines and determine the factors that lead to variability in results.

Methods

Two reviewers evaluated the direction and variabilities of MT and exercise literature. A red, yellow, and green light scoring system was used to define consistencies.

Results

Consistencies in responses were seen with acute and chronic exercise and both pro- and anti-inflammatory cytokines. Chronic exercise is associated with a consistent shift towards a more anti-inflammatory cytokine profile (Transforming Growth Factor-beta, and Interleukin-2 and 13, whereas acute bouts of intense exercise can transiently increase pro-inflammatory cytokine levels. The influence of MT on cytokines was less commonly studied and yielded more variable results.

Conclusion

Variability in findings is likely related to the subject and their baseline condition or disease, when measurement occurs, and the exercise intensity, duration, and an individual's overall health and fitness.

The effect of exercise intensity on chronic inflammation: A systematic review and meta-analysis

OBJECTIVES

Chronic inflammation is independently associated with the incidence and progression of chronic disease. Exercise has been found to reduce chronic inflammation, however the role of exercise intensity (work rate) is unknown. This review aimed to determine the pooled effect of higher- compared to lower-intensity aerobic and resistance exercise on chronic inflammation in adults.

DESIGN

Systematic review and meta-analysis.

METHODS

Five electronic databases were searched. Intervention trials that assessed the effect of ≥2 different exercise intensities on peripheral markers of chronic inflammation [c-reactive protein (CRP), interleukin (IL)-6, tumour necrosis factor (TNF)-α and IL-10] in adults were included. Random-effect meta-analyses were conducted to calculate the mean difference in change scores between groups [effect size (ES)]. Sub-group analyses were performed to explore the influence of age, chronic disease, body mass index and intervention duration on inflammation heterogeneity.

RESULTS

Of 3952 studies identified, 27 were included. There were no significant effects of exercise intensity on IL-6 (ES=-0.039, 95%CI=-0.353-0.275; p=0.806), TNF-α (ES=0.296, 95%CI=-0.184-0.777; p=0.227) and IL-10 (ES=0.007, 95%CI=-0.904-0.919; p=0.987). A significant pooled ES was observed for higher- versus lower-intensity exercise on CRP concentrations, in studies of middle-aged adults (ES=-0.412, 95%CI=-0.821- -0.004, p=0.048) or interventions >9 weeks in duration (ES=-0.520, 95%CI=-0.882--0.159, p=0.005).

CONCLUSIONS

Exercise intensity did not influence chronic inflammatory response. However, sub-analyses suggest that higher-intensity training may be more efficacious than lower-intensity for middle-aged adults, or when longer duration interventions are implemented (>9 weeks), in the most commonly-reported analyte (CRP).