Heat Reactions To Acute Exercise In Female Breast Cancer Survivors

Student thesis: Doctoral Thesis


This thesis aimed to take a multidisciplinary approach in the assessment of female breast cancer survivors’ (BCS) responses to acute exercise under different thermal environments.

Heat reactions can be reflected through core and skin temperature and sudomotor (sweat) responses. This thesis began with a technical approach to identify an array of sweat analysis techniques’ (whole body sweat rate, local sweat rate and sweat conductivity) reliability in a female population. A newly developed wearable sweat rate monitor was included in this reliability study to establish local sweat rate in real-time. The use of these sweat techniques was deemed appropriate and practical in females when exercising at a moderate intensity under heat stress conditions.

Study 2 assessed the validity of the wearable sweat rate monitor and the routine sweat analysis techniques, which were deemed reliable in Study 1. Construct validity was determined utilising a 5-day short-term heat acclimation intervention that demonstrated significant phenotypic adaptation across classic physiological markers (core temperature and heart rate). Importantly, sudomotor function significantly adapted across the sweat analysis techniques employed and therefore, all markers were deemed sensitive to adaptation, reinforcing their validity.

Data collection for both Study 3 and 4 was simultaneous. Study 3 incorporated all the above techniques, alongside physiological, inflammatory and perceptual markers to assess heat reactions in female BCS when compared to healthy age-matched females. An acute exercise intervention that replicated the daily recommended exercise guidelines (30-minutes moderate intensity exercise) followed by a self-paced functional performance test (6-minute walk test) was employed, in both warm (25°C, 50%RH) and hot conditions (35°C, 50%RH). There was no compromise in any inflammatory or perceptual parameters between BCS and controls. All physiological markers were higher during the 35°C vs. 25°C trial; Tre (~0.25°C, p < 0.01), Tskin (~3.8°C, p0.05). Both groups covered a greater 6MWT distance in 25°C vs. 35°C (by ~20m; p< 0.01). Nevertheless, the control group covered more distance than BCS, regardless of environmental temperature (by ~40m, p=0.03), potentially due to a reduced cardiac stability or anticipatory regulatory mechanism in BCS.

Study 4 focused on health-related quality of life (HRQoL) and hot flash differences (using the Hot Flash Related Daily Interference Scale, HRFDIS) between female BCS and healthy females, in two differing thermal environments, taken at baseline and 24-hours post acute exercise bout. A general HRQoL questionnaire was employed for both groups (PROMIS® Scale v1.2 – Global Health) with an additional questionnaire specifically for the BCS group (FACIT Functional Assessment of Cancer Therapy – Breast, FACT-B). No differences were observed in any of the HRQoL measures between populations, regardless of an increased prevalence of hot flashes in BCS.

Taken together, evidence in this thesis supports the notion that BCS are not disadvantaged when participating within government daily exercise recommendations in both warm and hot environments. This research, amongst the abundance of literature promoting regular physical activity for reduced cancer recurrence and many other health benefits, seeks to educate and motivate this population to be active. To conclude, the results of this thesis aim to be the foundation for further investigation of this population, where currently there is sparsity of research into their physiological responses to exercise, and especially when under heat stress conditions.
Date of Award2022
Original languageEnglish
Awarding Institution
  • University of Brighton
SupervisorLouisa Beale (Supervisor), Melanie Flint (Supervisor) & Neil Maxwell (Supervisor)

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