{"id":{"repo_id":"birmingham","oai_identifier":"oai:etheses.bham.ac.uk:471"},"canonical_url":"https://search.dev.ndltd.org/etd/birmingham/oai:etheses.bham.ac.uk:471","repository":{"repo_id":"birmingham","name":"University of Birmingham","base_url":"https://etheses.bham.ac.uk/cgi/oai2"},"display":{"title":"Mechanisms of fatigue during prolonged exercise in the heat","abstract":"Increase in body temperature is a major factor limiting endurance performance in the heat and it is shown in this thesis that the effects of raised body temperature on performance, perception and neuroendocrine response to exercise are mediated by an interaction of body temperatures. Prolactin has been used as an indicator of hypothalamic activity and the pathways regulating its release have been investigated using pindolol as a 5-HT\\(_{1A}\\) antagonist. The prolactin response to a buspirone challenge has been shown to be approximately 50% serotonergic and 50% dopaminergic, but with a wide inter-subject variation. Passive heating is a potent stimulus for prolactin release and it was shown that 5-HT\\(_{1A}\\) stimulation plays virtually no part in this process, raising the possibility that prolactin release during hyperthermic exercise may also be largely due to withdrawal of dopamine inhibition. A comparison of exercise tolerance in the heat and the sensitivity of central serotonergic and dopaminergic pathways further indicates the importance of dopamine in central fatigue. The action of caffeine in enhancing endurance performance has been shown not to involve the hypothalamus and this draws attention to other pathways that may be involved in central fatigue including the basal ganglia and limbic system.","abstract_html":"Increase in body temperature is a major factor limiting endurance performance in the heat and it is shown in this thesis that the effects of raised body temperature on performance, perception and neuroendocrine response to exercise are mediated by an interaction of body temperatures. Prolactin has been used as an indicator of hypothalamic activity and the pathways regulating its release have been investigated using pindolol as a 5-HT<span class=\"etd-inline-math\"><sub>1A</sub></span> antagonist. The prolactin response to a buspirone challenge has been shown to be approximately 50% serotonergic and 50% dopaminergic, but with a wide inter-subject variation. Passive heating is a potent stimulus for prolactin release and it was shown that 5-HT<span class=\"etd-inline-math\"><sub>1A</sub></span> stimulation plays virtually no part in this process, raising the possibility that prolactin release during hyperthermic exercise may also be largely due to withdrawal of dopamine inhibition. A comparison of exercise tolerance in the heat and the sensitivity of central serotonergic and dopaminergic pathways further indicates the importance of dopamine in central fatigue. The action of caffeine in enhancing endurance performance has been shown not to involve the hypothalamus and this draws attention to other pathways that may be involved in central fatigue including the basal ganglia and limbic system.","abstract_has_math":true,"creators":["Bridge, Matt"],"institution":"University of Birmingham","degree_name":"d_ph","degree_level":"d_ph","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002","date_published":"2002","updated_at":"2026-07-24T01:10:58Z","subjects":["RC1200 Sports Medicine","QP Physiology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.sponsor","label":"Sponsor","values":["na"]},{"key":"dc:creator","label":"Author","values":["Bridge, Matt"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2002"]},{"key":"dc:date.issued","label":"Date","values":["2002"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Sport & Exercise Science","School of Sport, Exercise and Rehabilitation Sciences"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Birmingham"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["http://etheses.bham.ac.uk//id/eprint/471/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["d_ph"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["d_ph"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["RC1200 Sports Medicine","QP Physiology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://etheses.bham.ac.uk//id/eprint/471/1/Bridge02PhD.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Increase in body temperature is a major factor limiting endurance performance in the heat and it is shown in this thesis that the effects of raised body temperature on performance, perception and neuroendocrine response to exercise are mediated by an interaction of body temperatures. Prolactin has been used as an indicator of hypothalamic activity and the pathways regulating its release have been investigated using pindolol as a 5-HT\\(_{1A}\\) antagonist. The prolactin response to a buspirone challenge has been shown to be approximately 50% serotonergic and 50% dopaminergic, but with a wide inter-subject variation. Passive heating is a potent stimulus for prolactin release and it was shown that 5-HT\\(_{1A}\\) stimulation plays virtually no part in this process, raising the possibility that prolactin release during hyperthermic exercise may also be largely due to withdrawal of dopamine inhibition. A comparison of exercise tolerance in the heat and the sensitivity of central serotonergic and dopaminergic pathways further indicates the importance of dopamine in central fatigue. The action of caffeine in enhancing endurance performance has been shown not to involve the hypothalamus and this draws attention to other pathways that may be involved in central fatigue including the basal ganglia and limbic system."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Mechanisms of fatigue during prolonged exercise in the heat"]}]}],"canonical_facts":{"dc:contributor.sponsor":["na"],"dc:creator":["Bridge, Matt"],"dc:date":["2002"],"dc:date.issued":["2002"],"dc:description.abstract":["Increase in body temperature is a major factor limiting endurance performance in the heat and it is shown in this thesis that the effects of raised body temperature on performance, perception and neuroendocrine response to exercise are mediated by an interaction of body temperatures. Prolactin has been used as an indicator of hypothalamic activity and the pathways regulating its release have been investigated using pindolol as a 5-HT\\(_{1A}\\) antagonist. The prolactin response to a buspirone challenge has been shown to be approximately 50% serotonergic and 50% dopaminergic, but with a wide inter-subject variation. Passive heating is a potent stimulus for prolactin release and it was shown that 5-HT\\(_{1A}\\) stimulation plays virtually no part in this process, raising the possibility that prolactin release during hyperthermic exercise may also be largely due to withdrawal of dopamine inhibition. A comparison of exercise tolerance in the heat and the sensitivity of central serotonergic and dopaminergic pathways further indicates the importance of dopamine in central fatigue. The action of caffeine in enhancing endurance performance has been shown not to involve the hypothalamus and this draws attention to other pathways that may be involved in central fatigue including the basal ganglia and limbic system."],"dc:format":["application/pdf"],"dc:identifier.uri":["http://etheses.bham.ac.uk//id/eprint/471/1/Bridge02PhD.pdf"],"dc:publisher.department":["School of Sport & Exercise Science","School of Sport, Exercise and Rehabilitation Sciences"],"dc:publisher.institution":["University of Birmingham"],"dc:relation.isreferencedby":["http://etheses.bham.ac.uk//id/eprint/471/"],"dc:subject":["RC1200 Sports Medicine","QP Physiology"],"dc:title":["Mechanisms of fatigue during prolonged exercise in the heat"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["d_ph"],"dc:type.qualificationname":["d_ph"]},"updated_at":"2026-07-24T01:10:58Z"}