Caffeine Increases Maximal Fat Oxidation During Exercise in Endurance-trained Men: is There a Diurnal Variation

Not Applicable

Completed

• Conditions: Energy Metabolism; Athletic Performance
• Interventions: Behavioral: Test in the morning; Behavioral: Test in the afternoon

• Registration Number: NCT04320446
• Lead Sponsor: Universidad de Granada

Brief Summary

Maximal fat oxidation during exercise (MFO) and the intensity of exercise that elicits MFO (Fatmax) has been recognized as potential determinants of endurance performance.

The purpose of this study was to determine the possible interaction between the effects of diurnal variation (morning vs. afternoon) and caffeine ingestion on MFO, Fatmax and VO2 max in endurance-trained men. Specifically, the investigators sought to elucidate whether the stimulant actions of caffeine could reverse the decrements of MFO and Fatmax observed in the morning.

Detailed Description

Body weight, height, body composition (DXA), exercise test (MFO and VO2max assessment) will be measured during the 4 evaluations.

Participants were randomized into 4 exercise test conditions:

1. Exercise test in the morning with placebo intake

2. Exercise test in the evening with placebo intake

3. Exercise test in the morning with caffeine intake

4. Execrise test in the evening with caffeine intake

Study Timeline

• Study Start: 2019-06-01
• Primary Completion: 2019-11-30
• Study Completion: 2019-11-30
• Status Verified: 2020-03
• Study First Submitted: 2020-03-19
• Study First Submitted QC: 2020-03-24
• Last Update Submitted: 2020-03-24
• Study First Posted: 2020-03-25
• Last Update Posted: 2020-03-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 15

Inclusion Criteria

• Having a body mass index (BMI) ranged from 18.5 to 28 kg/m2
• not suffering any specific disease which can be aggravated by physical exercise
• having previous experience in endurance training (i.e. self-reporting at least 2 years of cycling or running training including more than 3 training sessions/week).
• Participant must be capable and willing to provide consent, understand exclusion criteria, instructions and protocols.

Exclusion Criteria

• Being smoker
• Taking medication or drugs
• Any non-controlled medical condition which could influence results or could be worsened by the participation in the study
• Are deemed unsuitable by the investigator for any other reason, that prevent data collection.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo	Test in the afternoon	A dose of 3 mg/kg of placebo (i.e. 100% purity microcrystalline cellulose, Acofarma, Spain) was ingested before the beginning of each test.
Caffeine	Test in the morning	A dose of 3 mg/kg of caffeine (i.e. a vegetable extraction from green coffee beans, Harrison Sport Nutrition®, Spain) was ingested before the beginning of each test.
Caffeine	Test in the afternoon	A dose of 3 mg/kg of caffeine (i.e. a vegetable extraction from green coffee beans, Harrison Sport Nutrition®, Spain) was ingested before the beginning of each test.
Placebo	Test in the morning	A dose of 3 mg/kg of placebo (i.e. 100% purity microcrystalline cellulose, Acofarma, Spain) was ingested before the beginning of each test.

Primary Outcome Measures

Name	Time	Method
MFO	Through study completion, an average of 1 month	Maximal fat oxidation during exercise

Secondary Outcome Measures

Name	Time	Method
FATmax	Through study completion, an average of 1 month	The intensity of exercise that elicits MFO
VO2max	Through study completion, an average of 1 month	Cardiorrespiratory fitness measured by maximal oxygen uptake

Trial Locations

Locations (1)

Instituto Mixto Universitario Deporte Salud; 🇪🇸 Granada, Spain