Caffeine, Thermoregulation
Conditions
Keywords
caffeine, thermoregulation, time trial, exercise physiology
Brief summary
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.
Interventions
OTHERHot environment
Hot environment of 35 degrees Celsius
OTHERThermoneutral environment
Thermoneutral environment of 18 degrees Celsius
Sponsors
St. Mary's University, Twickenham
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
MALE
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy trained runners
Exclusion criteria
\-
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Blood lactate concentration | From baseline to completion, up to 31 days | Change from baseline in blood lactate concentration measured at rest and at five different exercise intensities (65, 70, 75, 80, and 85% percent of maximal oxygen uptake) on a treadmill. |
| Heart rate | From baseline to completion, up to 31 days | Change from baseline in heart rate measured at rest and at five different exercise intensities (65, 70, 75, 80, and 85% percent of maximal oxygen uptake) on a treadmill. |
| Rating of perceived exertion | From baseline to completion, up to 31 days | Change from baseline in rating of perceived exertion measured (using the 6-20 Borg scale) at five different exercise intensities (65, 70, 75, 80, and 85% percent of maximal oxygen uptake) on a treadmill. |
| Oxygen uptake | From baseline to completion, up to 31 days | Change from baseline in oxygen uptake measured at five different exercise intensities (65, 70, 75, 80, and 85% percent of maximal oxygen uptake) on a treadmill. |
| Time trial performance | From baseline to completion, up to 31 days | Change from baseline in distance covered during a 30 minute time trial on a treadmill. |
Contacts
Primary ContactMark Glaister
Outcome results
None listed