Purpose: The purpose of these studies was to observe the effect of dehydration on exercise performance while subjects were blinded to their hydration status. Methods: Study 1: Seven male cyclists (weight: 71±8 kg, body fat: 14±6%, VO2peak: 59.4±6 ml∙kg-1·min-1) exercised for 2 hours on a cycle ergometer at 55% VO2peak, in a hot-dry environment (35°C, 30% rh), with a nasogastric (NG) tube under euhydrated (EUH-NT) and hypohydrated (DEH-NT) conditions. In both trials, thirst was matched by drinking 25 mL every 5 min. In the EUH-NT trial sweat losses were fully replaced via the NG tube. Following the 2 hours of steady state, the cyclists completed a 5-kilometer cycling time trial at 4% grade. Study 2: Eleven male cyclists (weight 75.8±6.4 kg, VO2peak: 64.9±5.6 mL·kg·min-1, body fat: 12.0±5.8%) performed three sets of criterium-like cycling, consisting of 20 min of steady state cycling at 50% peak power output, each followed by a 5-km time-trial at 3% grade. Subjects completed the protocol on two separate occasions either hypohydrated (HYP) or euhydrated (EUH). In both trials, subjects ingested 25 mL every 5 min during the steady-state and 25 mL every 1-km during the 5-km time-trials. In the EUH trial, sweat losses were fully replaced via intravenous infusion of isotonic saline while in the DEH trial, a sham IV was instrumented. Results: In Study 1, cyclists completed the 5-km time trial faster in the EUH-NT trial compared to the DEH-NT trial (23.2±0.2 vs. 22.3±0.3 km·h-1, P<0.05), while producing higher power output (295±29 vs. 270±26 W, P<0.05). In Study 2, during the second and third time-trials, subjects displayed faster speed in the EUH trial (27.5±3.0 and 27.2±3.1 km·h-1) compared to the HYP trial (26.2±2.9 and 25.5±3.3 km·h-1; both P<0.05). Core temperature (Tre) was also higher in the HYP trial throughout the third steady-state (P<0.05) and continued to be higher throughout the third 5-km time-trial (P<0.05). Conclusions: These data suggest that full fluid replacement, even in a blinded manner, provided a performance advantage by maintaining better hydration state. This benefit seems to be associated with the lower thermoregulatory strain, due to lower core temperatures.
","abstract_html":"<p>Purpose: The purpose of these studies was to observe the effect of dehydration on exercise performance while subjects were blinded to their hydration status. Methods: Study 1: Seven male cyclists (weight: 71±8 kg, body fat: 14±6%, VO2peak: 59.4±6 ml∙kg-1·min-1) exercised for 2 hours on a cycle ergometer at 55% VO2peak, in a hot-dry environment (35°C, 30% rh), with a nasogastric (NG) tube under euhydrated (EUH-NT) and hypohydrated (DEH-NT) conditions. In both trials, thirst was matched by drinking 25 mL every 5 min. In the EUH-NT trial sweat losses were fully replaced via the NG tube. Following the 2 hours of steady state, the cyclists completed a 5-kilometer cycling time trial at 4% grade. Study 2: Eleven male cyclists (weight 75.8±6.4 kg, VO2peak: 64.9±5.6 mL·kg·min-1, body fat: 12.0±5.8%) performed three sets of criterium-like cycling, consisting of 20 min of steady state cycling at 50% peak power output, each followed by a 5-km time-trial at 3% grade. Subjects completed the protocol on two separate occasions either hypohydrated (HYP) or euhydrated (EUH). In both trials, subjects ingested 25 mL every 5 min during the steady-state and 25 mL every 1-km during the 5-km time-trials. In the EUH trial, sweat losses were fully replaced via intravenous infusion of isotonic saline while in the DEH trial, a sham IV was instrumented. Results: In Study 1, cyclists completed the 5-km time trial faster in the EUH-NT trial compared to the DEH-NT trial (23.2±0.2 vs. 22.3±0.3 km·h-1, P<0.05), while producing higher power output (295±29 vs. 270±26 W, P<0.05). In Study 2, during the second and third time-trials, subjects displayed faster speed in the EUH trial (27.5±3.0 and 27.2±3.1 km·h-1) compared to the HYP trial (26.2±2.9 and 25.5±3.3 km·h-1; both P<0.05). Core temperature (Tre) was also higher in the HYP trial throughout the third steady-state (P<0.05) and continued to be higher throughout the third 5-km time-trial (P<0.05). Conclusions: These data suggest that full fluid replacement, even in a blinded manner, provided a performance advantage by maintaining better hydration state. This benefit seems to be associated with the lower thermoregulatory strain, due to lower core temperatures. </p>","abstract_has_math":false,"creators":["Adams, Jon David"],"institution":null,"degree_name":"Doctor of Philosophy in Kinesiology (PhD)","degree_level":"Dissertation","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Mauromoustakos, Andronikos T.","Ganio, Matthew S."],"advisors":["Kavouras, Stavros A."],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017-08-01T07:00:00Z","date_published":"2017-08-01T07:00:00Z","updated_at":"2026-07-24T01:00:28Z","subjects":["Exercise Performance","Hydration","Thermoregulation","Exercise Physiology","Exercise Science","Human and Clinical Nutrition"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarworks.uark.edu/etd/2394","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mauromoustakos, Andronikos T.","Ganio, Matthew S."]},{"key":"dc:contributor.advisor","label":"Advisor","values":["Kavouras, Stavros A."]},{"key":"dc:creator","label":"Author","values":["Adams, Jon David"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2024-02-06T08:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy in Kinesiology (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Exercise Performance","Hydration","Thermoregulation","Exercise Physiology","Exercise Science","Human and Clinical Nutrition"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarworks.uark.edu/etd/2394"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Purpose: The purpose of these studies was to observe the effect of dehydration on exercise performance while subjects were blinded to their hydration status. Methods: Study 1: Seven male cyclists (weight: 71±8 kg, body fat: 14±6%, VO2peak: 59.4±6 ml∙kg-1·min-1) exercised for 2 hours on a cycle ergometer at 55% VO2peak, in a hot-dry environment (35°C, 30% rh), with a nasogastric (NG) tube under euhydrated (EUH-NT) and hypohydrated (DEH-NT) conditions. In both trials, thirst was matched by drinking 25 mL every 5 min. In the EUH-NT trial sweat losses were fully replaced via the NG tube. Following the 2 hours of steady state, the cyclists completed a 5-kilometer cycling time trial at 4% grade. Study 2: Eleven male cyclists (weight 75.8±6.4 kg, VO2peak: 64.9±5.6 mL·kg·min-1, body fat: 12.0±5.8%) performed three sets of criterium-like cycling, consisting of 20 min of steady state cycling at 50% peak power output, each followed by a 5-km time-trial at 3% grade. Subjects completed the protocol on two separate occasions either hypohydrated (HYP) or euhydrated (EUH). In both trials, subjects ingested 25 mL every 5 min during the steady-state and 25 mL every 1-km during the 5-km time-trials. In the EUH trial, sweat losses were fully replaced via intravenous infusion of isotonic saline while in the DEH trial, a sham IV was instrumented. Results: In Study 1, cyclists completed the 5-km time trial faster in the EUH-NT trial compared to the DEH-NT trial (23.2±0.2 vs. 22.3±0.3 km·h-1, P<0.05), while producing higher power output (295±29 vs. 270±26 W, P<0.05). In Study 2, during the second and third time-trials, subjects displayed faster speed in the EUH trial (27.5±3.0 and 27.2±3.1 km·h-1) compared to the HYP trial (26.2±2.9 and 25.5±3.3 km·h-1; both P<0.05). Core temperature (Tre) was also higher in the HYP trial throughout the third steady-state (P<0.05) and continued to be higher throughout the third 5-km time-trial (P<0.05). Conclusions: These data suggest that full fluid replacement, even in a blinded manner, provided a performance advantage by maintaining better hydration state. This benefit seems to be associated with the lower thermoregulatory strain, due to lower core temperatures.
"]},{"key":"dc:title","label":"Title","values":["The Effect of Blinded Hydration State on Thermoregulation and Performance in Male Cyclists"]}]}],"canonical_facts":{"dc:contributor":["Mauromoustakos, Andronikos T.","Ganio, Matthew S."],"dc:contributor.advisor":["Kavouras, Stavros A."],"dc:creator":["Adams, Jon David"],"dc:date":["2017"],"dc:date.available":["2024-02-06T08:00:00Z"],"dc:description.abstract":["Purpose: The purpose of these studies was to observe the effect of dehydration on exercise performance while subjects were blinded to their hydration status. Methods: Study 1: Seven male cyclists (weight: 71±8 kg, body fat: 14±6%, VO2peak: 59.4±6 ml∙kg-1·min-1) exercised for 2 hours on a cycle ergometer at 55% VO2peak, in a hot-dry environment (35°C, 30% rh), with a nasogastric (NG) tube under euhydrated (EUH-NT) and hypohydrated (DEH-NT) conditions. In both trials, thirst was matched by drinking 25 mL every 5 min. In the EUH-NT trial sweat losses were fully replaced via the NG tube. Following the 2 hours of steady state, the cyclists completed a 5-kilometer cycling time trial at 4% grade. Study 2: Eleven male cyclists (weight 75.8±6.4 kg, VO2peak: 64.9±5.6 mL·kg·min-1, body fat: 12.0±5.8%) performed three sets of criterium-like cycling, consisting of 20 min of steady state cycling at 50% peak power output, each followed by a 5-km time-trial at 3% grade. Subjects completed the protocol on two separate occasions either hypohydrated (HYP) or euhydrated (EUH). In both trials, subjects ingested 25 mL every 5 min during the steady-state and 25 mL every 1-km during the 5-km time-trials. In the EUH trial, sweat losses were fully replaced via intravenous infusion of isotonic saline while in the DEH trial, a sham IV was instrumented. Results: In Study 1, cyclists completed the 5-km time trial faster in the EUH-NT trial compared to the DEH-NT trial (23.2±0.2 vs. 22.3±0.3 km·h-1, P<0.05), while producing higher power output (295±29 vs. 270±26 W, P<0.05). In Study 2, during the second and third time-trials, subjects displayed faster speed in the EUH trial (27.5±3.0 and 27.2±3.1 km·h-1) compared to the HYP trial (26.2±2.9 and 25.5±3.3 km·h-1; both P<0.05). Core temperature (Tre) was also higher in the HYP trial throughout the third steady-state (P<0.05) and continued to be higher throughout the third 5-km time-trial (P<0.05). Conclusions: These data suggest that full fluid replacement, even in a blinded manner, provided a performance advantage by maintaining better hydration state. This benefit seems to be associated with the lower thermoregulatory strain, due to lower core temperatures.
"],"dc:identifier":["https://scholarworks.uark.edu/etd/2394"],"dc:subject":["Exercise Performance","Hydration","Thermoregulation","Exercise Physiology","Exercise Science","Human and Clinical Nutrition"],"dc:title":["The Effect of Blinded Hydration State on Thermoregulation and Performance in Male Cyclists"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy in Kinesiology (PhD)"]},"updated_at":"2026-07-24T01:00:28Z"}