Exercise and the gut microbiome: implications for supportive care in cancer.

PURPOSE: Growing recognition of the gut microbiome as an influential modulator of cancer treatment efficacy and toxicity has led to the emergence of clinical interventions targeting the microbiome to enhance cancer and health outcomes. The highly modifiable nature of microbiota to endogenous, exogenous, and environmental inputs enables interventions to promote resilience of the gut microbiome that have rapid effects on host health, or response to cancer treatment. While diet, probiotics, and faecal microbiota transplant are primary avenues of therapy focused on restoring or protecting gut function in people undergoing cancer treatment, the role of physical activity and exercise has scarcely been examined in this population. METHODS: A narrative review was conducted to explore the nexus between cancer care and the gut microbiome in the context of physical activity and exercise as a widely available and clinically effective supportive care strategy used by cancer survivors. RESULTS: Exercise can facilitate a more diverse gut microbiome and functional metabolome in humans; however, most physical activity and exercise studies have been conducted in healthy or athletic populations, primarily using aerobic exercise modalities. A scarcity of exercise and microbiome studies in cancer exists. CONCLUSIONS: Exercise remains an attractive avenue to promote microbiome health in cancer survivors. Future research should elucidate the various influences of exercise modalities, intensities, frequencies, durations, and volumes to explore dose-response relationships between exercise and the gut microbiome among cancer survivors, as well as multifaceted approaches (such as diet and probiotics), and examine the influences of exercise on the gut microbiome and associated symptom burden prior to, during, and following cancer treatment.

Exercise-induced changes to the human gut microbiota and implications for colorectal cancer: a narrative review.

Physical activity is associated with reduced risks of colorectal cancer (CRC) incidence, recurrence and mortality. While these findings are consistent, the mechanism/s underlying this association remain unclear. Growing evidence supports the many ways in which differing characteristics of the gut microbiota can be tumourigenic or protective against CRC. CRC is characterised by significant dysbiosis including reduced short chain fatty acid-producing bacteria. Recent findings suggest that exercise can modify the gut microbiota, and these changes are inverse to the changes seen with CRC; however, this exercise-microbiota interaction is currently understudied in CRC. This review summarises parallel areas of research that are rapidly developing: The exercise-gut microbiota research and cancer-gut microbiota research and highlights the salient similarities. Preliminary evidence suggests that these areas are linked, with exercise mediating changes that promote the antitumorigenic characteristics of the gut microbiota. Future mechanistic and population-specific studies are warranted to confirm the physiological mechanism/s by which exercise changes the gut microbiota, and the influence of the exercise-gut interaction on cancer specific outcomes in CRC.

The Effect of Exercise Prescription on the Human Gut Microbiota and Comparison between Clinical and Apparently Healthy Populations: A Systematic Review.

This study systematically reviewed all human longitudinal exercise interventions that reported changes in the gut microbiota; frequency, intensity, duration and type of exercise were assessed to determine the influence of these variables on changes to the gut microbiota in both healthy individuals and clinical populations (PROPERO registration: CRD42022309854). Using PRISMA guidelines, trials analysing gut microbiota change with exercise interventions were included independent of trial randomisation, population, trial duration or analysis technique. Studies were excluded when microbiota abundance was not reported or when exercise was combined with other interventions. Twenty-eight trials were included, of which twelve involved healthy populations only and sixteen involved mixed or clinical-only populations. The findings show that participation in exercise of moderate to high-intensity for 30-90 min ≥3 times per week (or between 150-270 min per week) for ≥8 weeks is likely to produce changes in the gut microbiota. Exercise appears to be effective in modifying the gut microbiota in both clinical and healthy populations. A more robust methodology is needed in future studies to improve the certainty of the evidence.

Safety, Feasibility, and Acceptability of a Multisite Individualized Exercise Intervention for People with Multiple Myeloma.

INTRODUCTION: High rates of disease- and treatment-related symptoms, such as bone lesions, in people with multiple myeloma (MM) create uncertainty on the safety and feasibility of exercise. This study determined the safety, feasibility, and acceptability of an individualized exercise medicine program for people with MM at any disease stage. METHODS: A multisite, randomized waitlist-controlled trial was conducted of an individualized, high-intensity aerobic, resistance, and impact-loading exercise program. The exercise sessions were supervised twice weekly by accredited exercise physiologists, with one additional unsupervised session per week, for 12 wk. Safety was determined by number of adverse and serious adverse events. Feasibility outcome measures were study eligibility, recruitment, adherence, and attrition. Acceptability was determined by qualitative interviews and subjective levels of enjoyment. RESULTS: Of 203 people with MM screened, 88% were eligible, with 34% accepting participation (60 people) and 20% attrition for the between-group analysis, meeting a priori criteria (≥25% and <25%, respectively). No adverse or serious adverse events attributed to testing and/or exercise training were reported. Attendance at supervised exercise sessions was 98%, with 45% completion of the home-based exercise sessions. Adherence rates were 35%, 63%, and 34% for the aerobic, resistance, and impact-loading protocols, with 55%, 80%, and 37% of participants meeting a priori criteria (75% of protocol). Acceptability of the exercise program was high (mean, 82%; 95% confidence interval, 78%-87%) and highly supported by qualitative responses. CONCLUSIONS: An individualized, high-intensity aerobic, resistance, and impact-loading exercise medicine program is safe and acceptable, and feasible by some measures for people with MM. Adherence to the prescribed exercise protocols was limited by comorbidities and disease symptoms. Strategies to improve unsupervised exercise completion are warranted in this population.

Aviation Rescue Firefighters physical fitness and predictors of task performance.

OBJECTIVES: Aviation Rescue Firefighters (ARFF) require physical fitness specific to the aviation environment. This study aims to determine the physical fitness of ARFF and predictors of performance on ARFF-specific tasks from laboratory-based fitness measures. DESIGN: Cross-sectional, observational study. METHODS: Forty-two male ARFF (mean±SD; age 38.4±7.6 years, body mass index 26.2±2.2kgm-2) completed a physical fitness testing battery, comprising maximal aerobic capacity (V˙O2max), lactate threshold, anaerobic power, body composition (dual-energy X-ray absorptiometry), muscular strength (3 repetition maximum (3RM) bench and leg press) and muscular endurance (maximum curl ups and push ups) under controlled laboratory conditions. On a separate occasion, ARFF completed timed work-related tasks including a hose drag, dummy drag, Stihl saw hold, stair climb and simulated ARFF emergency protocol. RESULTS: All participants finished the simulated ARFF emergency protocol under the criterion time (5min 50s); the average completion time was 4min and 31s. Performance time on the simulated ARFF emergency protocol was inversely correlated to V˙O2max (r=-0.514; p<0.001), anaerobic step test performance (r=-0.549; p<0.001), height (r=-0.325; p=0.038) and lean mass (r=-0.429; p=0.005). Higher fat mass (r=0.318; p=0.043) and % body fat (r=0.481; p=0.001) were associated with slower performance time. Muscular strength, muscular endurance and flexibility were not related to performance on the simulated ARFF emergency protocol. CONCLUSIONS: Aerobic and anaerobic capacities, as well as body composition are the strongest predictors of simulated ARFF emergency protocol performance. This study highlights the importance of aerobic and anaerobic fitness, compared to muscular strength or muscular endurance, for ARFF job-specific performance, employment and training.