• Login
    View Item 
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    •   Home
    • Massey Documents by Type
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Human temperature regulation during exercise in the heat : effects of the menstrual cycle and ambient thermal profile : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy, School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand

    Icon
    View/Open Full Text
    01_front.pdf (543.5Kb)
    02_whole.pdf (5.696Mb)
    Export to EndNote
    Abstract
    Behavioural thermoregulation is the most effective means with which we regulate our body temperature at rest and during exercise. Yet, research into behavioural thermoregulation during exercise is still at an emergent stage, as it has not included females, or investigated different thermal profiles. In particular, limited studies are available to describe the behavioural and physiological differences between dry and humid heat for both sexes. Furthermore, it remains unknown whether ambient humidity or temperature alone contribute to the initiation of the behavioural responses during exercise in the heat. Therefore, the first part of this thesis investigated the effects of endogenous and exogenous female ovarian hormones on behavioural and autonomic responses, in both dry and humid heat environments matched according to the heat stress index, WBGT (Chapter Five and Six). The results from Chapter Five clearly show that behavioural and autonomic responses were less affected by menstrual phase, but were affected by the environmental conditions. In particular, trained women reduced their power output in order to nullify the autonomic strain from a humid heat environment. Chapter Six then extended this observation to (trained) women taking combined hormonal contraception, compared to eumenorrheic women in Chapter Five. The results from Chapter Six indicate that greater autonomic strain was observed in women with hormonal contraception, compared to eumenorrheic women, in both dry and humid heat, whilst the behavioural response was similar between those two groups. Furthermore, the behavioural response was different between dry and humid heat, with power output being lower in the humid heat environment compared to dry heat. The second part of this thesis investigated the effects of ambient temperature per se on the interaction of thermoregulatory, cardiovascular and perceptual responses to exercise (Chapter Seven), as well as assessing different exercise modalities (variable-intensity versus fixed-intensity exercise) and their effects on thermoregulation when the duration and average power output were matched (Chapter Eight). The results from Chapter Seven indicate that thermoregulatory and cardiovascular responses were not affected by ambient temperature but that perception was, when vapour pressure was matched between two different thermal profiles. The results from Chapter Eight indicate that self-pacing (behaviour) did not modulate thermoregulatory strain, when both self-paced and fixed-intensity were matched at the same exercise intensity and duration. In conclusion, this thesis extends the knowledge-base on behavioural thermoregulation in trained women and also provides evidence that behavioural and autonomic thermoregulation is influenced more by vapour pressure than ambient temperature of the environment in men. Furthermore, the findings of this thesis confirm that behavioural thermoregulation is effective in modulating physiological strain only when there is a reduction in metabolic heat production.
    Date
    2018
    Author
    Lei, Tze-Huan
    Rights
    The Author
    Publisher
    Massey University
    Description
    Figures 3 (p.12), 5 (p.15), 6 (p.17), 7 (p.23), 8 (p.27), 9 (p.29), 10 (p.32) & 11 (p.39) have been removed for copyright reasons, but may be accessed via their source listed in the References. Figure 11 is accessible via https://theconversation.com/blood-sweat-and-tears-the-menstrual-cycle-and-the-olympics-8099
    URI
    http://hdl.handle.net/10179/14959
    Collections
    • Theses and Dissertations
    Metadata
    Show full item record

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1
     

     

    Tweets by @Massey_Research
    Information PagesContent PolicyDepositing content to MROCopyright and Access InformationDeposit LicenseDeposit License SummaryTheses FAQFile FormatsDoctoral Thesis Deposit

    Browse

    All of MROCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Copyright © Massey University
    | Contact Us | Feedback | Copyright Take Down Request | Massey University Privacy Statement
    DSpace software copyright © Duraspace
    v5.7-2020.1-beta1