Effects of Pre-Exercise Nutrition Strategies on Body Temperature and Thermoregulatory Responses

Overview

Carbohydrate ingestion, in particular fructose, has been shown in a handful of previous studies to elicit a thermic effect and increase core body temperature after ingestion. Carbohydrate foods and supplements are commonly consumed prior to endurance running competition, including situations where an athlete's ability to dissipate body heat is compromised. Thus, there is some potential for pre-exercise carbohydrate ingestion to have a deleterious effect on body heat regulation in hot and humid environments. Thus, this projects aims to study the effects of pre-exercise carbohydrate ingestion on core body temperature, perceived thermal stress, and perceived exertion during high-intensity running.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Basic Science
    • Masking: Double (Participant, Investigator)
  • Study Primary Completion Date: September 2017

Interventions

  • Other: Carbohydrate Beverage
    • 750 ml of a 13.5% carbohydrate (sucrose) beverage
  • Other: Placebo Beverage
    • 750 ml of an artificially-sweetened beverage

Arms, Groups and Cohorts

  • Experimental: Carbohydrate Beverage
  • Placebo Comparator: Placebo Beverage

Clinical Trial Outcome Measures

Primary Measures

  • Core Body Temperature
    • Time Frame: 80 minutes (60, 50, 40, 30, 20, and 10 min pre-run and at 1-km intervals during a 20 min 5-km run)
    • Core body temperature will be measured with a ingestible pill thermometer. Readings will be taken during a 60 minute rest period and at 1-km intervals during a 5-km run.

Secondary Measures

  • Thermal Sensation Scale
    • Time Frame: 80 minutes (60, 50, 40, 30, 20, and 10 min pre-run and at 1-km intervals during a 20 min 5-km run)
    • The Thermal Sensation Scale is a 0-8 numerical rating scale with descriptors of “unbearably cold” at 0, “neutral” at 4, and “unbearably hot” at 8. These ratings will be collected during a 60 minute rest period and at 1-km intervals during a 5-km run.
  • Feeling Scale
    • Time Frame: 80 minutes (60, 50, 40, 30, 20, and 10 min pre-run and at 1-km intervals during a 20 min 5-km run)
    • The Feeling Scale is a bipolar numerical rating scale ranging from -5 to +5, with descriptors of “very bad” at -5, “neutral” at 0, and “very good” at +5. These ratings will be collected during a 60 minute rest period and at 1-km intervals during a 5-km run.
  • Rating of Perceived Exertion
    • Time Frame: 80 minutes (60, 50, 40, 30, 20, and 10 min pre-run and at 1-km intervals during a 20 min 5-km run)
    • These ratings will be collected during a 60 minute rest period and at 1-km intervals during a 5-km run.

Participating in This Clinical Trial

Inclusion Criteria

  • Be currently running ≥20 miles per week – Have a projected 5-km maximal effort running time between 16:00-23:00 minutes Exclusion Criteria:

  • Any gastrointestinal disorders that cause swallowing problems or frequent nausea/vomiting

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 65 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Old Dominion University
  • Provider of Information About this Clinical Study
    • Principal Investigator: Patrick Wilson, PhD, Assistant Professor of Exercise Science – Old Dominion University

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