The association between time-of-day of habitual exercise training and changes in relevant cancer health outcomes among cancer survivors

Objective To assess the relationship between time-of-day of exercise training and changes in relevant cancer health outcomes among cancer survivors. Methods Retrospective analysis of data collected from 2016–2019 from a hospital-based exercise oncology program. Descriptive statistics were calculated for demographic, clinical, and exercise timing characteristics (e.g. AM, PM, or mix) among survivors with available data for exercise training time (n = 233). For the total sample and a breast cancer sub-analysis, univariate analysis of covariance, adjusted for age, was carried out by exercise training time, for change in the following outcomes collected during the program’s assessment sessions: cardiorespiratory fitness and muscular endurance (human performance variables), physical function, anthropometrics, self-reported fatigue, and quality of life (QoL). Change in body mass index (BMI) and body weight was included in the breast cancer analysis. Results Overall, 37.3% of survivors habitually engaged in AM exercise (e.g. ≥ 75% AM training), 34.3% in PM exercise, and 28.3% in a mix of AM and PM exercise training throughout the program. Median time in the program was 17 weeks. Significant improvements in most human performance and physical function variables were observed in the total sample regardless of exercise training time-of-day. Among breast cancer survivors, PM but not AM or mixed was associated with improvements in fitness, and lower-body muscular endurance and function. Mixed exercise timing was linked with greater increase in waist circumference (total sample: 3.02cm, 95%CI 1.55, 4.49; breast cancer: 3.57cm 95%CI 0.96, 6.18), body weight (breast cancer: 1.6kg, 95%CI 0.3, 2.8) and BMI (breast cancer: 0.6kg/m2, 95%CI 0.1, 1.0). AM and PM exercise, but not mixed, was associated with improvements in fatigue and QoL. Conclusion Time-of-day of exercise training may differentially impact changes in human performance and physical function variables. Mixed exercise training time may result in less favorable outcomes related of weight management variables among cancer survivors.

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Updated systematic review of exercise studies in breast cancer survivors: attention to the principles of exercise training

British Journal of Sports Medicine ◽

10.1136/bjsports-2017-098389 ◽

2017 ◽

Vol 53 (8) ◽

pp. 504-512 ◽

Cited By ~ 31

Author(s):

Sarah E Neil-Sztramko ◽

Kerri M Winters-Stone ◽

Kelcey A Bland ◽

Kristin L Campbell

Keyword(s):

Breast Cancer ◽

Systematic Review ◽

Exercise Training ◽

Cancer Survivors ◽

Randomised Controlled Trials ◽

Breast Cancer Survivors ◽

Exercise Prescription ◽

Controlled Trials ◽

Exercise Interventions ◽

Randomised Controlled

ObjectivesTo update our previous evaluation of the exercise interventions used in randomised controlled trials of breast cancer survivors in relation to (1) the application of the principles of exercise training in the exercise prescription; (2) the reporting of the components of the exercise prescription; and (3) the reporting of adherence of participants to the prescribed interventions.DesignSystematic review.Data sourcesThe OVID Medline, Embase, CINAHL and SPORTDiscus electronic databases were searched from January 2010 to January 2017.Eligibility criteriaRandomised controlled trials of at least 4 weeks of aerobic and/or resistance exercise in women diagnosed with breast cancer, reporting on physical fitness or body composition outcomes.ResultsSpecificity was appropriately applied by 84%, progression by 29%, overload by 38% and initial values by 67% of newly identified studies. Reversibility was reported by 3% anddiminishing returns by 22% of newly identified studies. No studies reported all components of the exercise prescription in the methods, or adherence to the prescribed intervention in the results. Reporting of reversibility has increased from 2010, but no other improvements in reporting were noted from the previous review.Summary/ConclusionNo studies of exercise in women with breast cancer attended to all principles of exercise training, or reported all components of the exercise prescription in the methods, or adherence to the prescription in the results. Full reporting of the exercise prescribed and completed is essential for study replication in research and translating research findings into the community, and should be prioritised in future trials.

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