The Effects of Caffeine on Exercise Physiology and Time-trial Performance in a Hot Environment

St. Mary's University, Twickenham

Status: Not yet enrolling

Conditions: Caffeine; Thermoregulation

Treatments: Other: Hot environment; Other: Thermoneutral environment

Study type: Interventional

Funder types: Other

Identifiers

NCT07129200

SMU_ETHICS_2024-25_1111

Details and patient eligibility

About

Maintaining a stable core temperature is vital for physiological function; yet, exercise in heat can be problematic, and there is risk of exertional heat-related illness (Flouris & Schlader, 2015; Leyk et al., 2019; Périard et al., 2021; Tyler et al., 2016; Veltmeijer et al., 2015). While aerobic fitness improves heat tolerance (Alhadad et al., 2019), strategies like acclimation and pre-cooling also mitigate heat stress (Casadio et al., 2016; Lorenzo et al., 2010; Ross et al., 2013; Siegel et al., 2010). Caffeine, an ergogenic aid (Del Corso et al., 2011; John et al., 2024), is known to enhance performance via adenosine antagonism and increased catecholamines in normothermic environments (Fredholm et al., 1999; Graham & Spriet, 1991). However, effects in heat are inconsistent (Ganio et al., 2009; Zhang et al., 2014), possibly due to caffeine reducing the ability to thermoregulate effectively. Therefore, the aim of this study is to investigate the effects of a moderate dose of caffeine (5 mg/kg) on thermoregulation during a 30-minute running time trial in 35°C heat.

Enrollment: 15 estimated patients

Sex: Male

Ages: 18 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy trained runners

Exclusion criteria

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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15 participants in 2 patient groups, including a placebo group

Caffeine

Experimental group

Description:

5 mg/kg dose of caffeine (in pill form)

Treatment:

Other: Thermoneutral environment

Other: Hot environment

Placebo

Placebo Comparator group

Description:

5 mg/kg dose of placebo (maltodextrin - in pill form)

Treatment:

Other: Thermoneutral environment

Other: Hot environment