Lower rate-pressure product during submaximal walking: a link to fatigue improvement following a physical activity intervention among breast cancer survivors

Abstract

PURPOSE Research showing a link between exercise-induced changes in aerobic fitness and reduced fatigue after a cancer diagnosis has been inconsistent. We evaluated associations of fatigue and rate-pressure product (RPP), a reliable index of myocardial oxygen demand, at rest and during submaximal walking following a physical activity intervention among post-primary treatment breast cancer survivors (BCS). METHODS Secondary analyses of 152 BCS in a randomized controlled trial testing a physical activity intervention (INT) versus usual care (UC) were performed. The INT group completed counseling/group discussions along with supervised exercise sessions tapered to unsupervised exercise. Evaluations were made at baseline and immediately post-intervention (M3) on measures of physical activity (accelerometry), graded-walk test, and average fatigue over the previous 7 days. RPP was calculated by dividing the product of heart rate and systolic blood pressure by 100. RESULTS Resting and submaximal RPPs were significantly improved in both groups at M3, however, the magnitude of change (Δ) was greater in the INT group from stage 1 (ΔRPP1; INT −13±17 vs. UC −7±18; p=0.03) through stage 4 (ΔRPP4; INT −21±26 vs. UC −9±24; p<0.01) of the walk test. The INT group reported significantly reduced fatigue (INT −0.7±2.0 vs. UC +0.1±2.0; p=0.02) which was positively associated with ΔRPP during stages 2–4 of the walk test but not Δaerobic fitness. CONCLUSIONS Lower RPP during submaximal walking was significantly associated with reduced fatigue in BCS. IMPLICATIONS FOR CANCER SURVIVORS Exercise/physical activity training programs that lower the physiological strain during submaximal walking may produce the largest improvements in reported fatigue.

Ease of walking associates with greater free-living physical activity and reduced depressive symptomology in breast cancer survivors: pilot randomized trial

“…At the onset of physical exertion, there is an intensity-dependent rise in heart rate to ensure tissue perfusion matches metabolic demands. For a given workload, a lower heart rate is a phenotypic response to habitual exercise training that parallels greater physiologic reserve [41]. In the present study, heart rate and VO 2 were significantly reduced during the standardized walking test post-intervention.…”

Benefits of Aerobic Exercise for Breast Cancer Survivors: A Systematic Review of Randomized Controlled Trials

“…All included studies were of low risk in terms of selective reporting and attrition bias. Only five studies were of low risk of bias in terms of allocation concealment (Carter et al, 2016;Irwin et al, 2008;Murtezani et al, 2014;Roveda et al, 2016;Saarto et al, 2012), while three studies were of low risk of bias in terms of blinding the participants/personnel (Campbell et al, 2017;Fairey et al, 2005;. The summary of risk of bias assessment is shown in Figure 2, and the reasons for authors' judgments are shown in Table S2 of Supplementary material.…”

Effects of a multicomponent physical activity behavior change intervention on fatigue, anxiety, and depressive symptomatology in breast cancer survivors: randomized trial

“…Exercise has demonstrated promise as a nonpharmacologic therapy for these symptoms with potential underlying mechanisms including beneficial changes in inflammation, hormone profiles, body composition, cardiorespiratory endurance, and autonomic function . These exercise benefits, along with others, documented by exercise training trials have motivated the development and testing of physical activity behavior change interventions aimed at translating these findings to a larger number of breast cancer survivors by focusing on increasing physical activity adherence.…”