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

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.

Study Overview

• Status: Completed
• Conditions: Athletic Performance; Energy Metabolism
• Intervention / Treatment: Behavioral: Test in the morning; Behavioral: Test in the afternoon

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 Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Granada, Spain, 18016
    • Instituto Mixto Universitario Deporte Salud

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 40 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Male

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Caffeine; 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.	Behavioral: Test in the morning; The exercise test was performed between 8 a.m and 11 a.m; Other Names: MFO-morning, Fatmax-morning, and VO2max-morning; Behavioral: Test in the afternoon; The exercise test was performed between 5 p.m. and 8 p.m.a; Other Names: (MFO-afternoon, Fatmax-afternoon, and VO2max-afternoon
Placebo Comparator: Placebo; A dose of 3 mg/kg of placebo (i.e. 100% purity microcrystalline cellulose, Acofarma, Spain) was ingested before the beginning of each test.	Behavioral: Test in the morning; The exercise test was performed between 8 a.m and 11 a.m; Other Names: MFO-morning, Fatmax-morning, and VO2max-morning; Behavioral: Test in the afternoon; The exercise test was performed between 5 p.m. and 8 p.m.a; Other Names: (MFO-afternoon, Fatmax-afternoon, and VO2max-afternoon

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MFO	Maximal fat oxidation during exercise	Through study completion, an average of 1 month

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Universidad de Granada
• Investigators: Principal Investigator: Jonatan Ruiz Ruiz, Dr., Universidad de Granada

Publications and helpful links

General Publications

• Ramirez-Maldonado M, Jurado-Fasoli L, Del Coso J, R Ruiz J, Amaro-Gahete FJ. Caffeine increases maximal fat oxidation during a graded exercise test: is there a diurnal variation? J Int Soc Sports Nutr. 2021 Jan 7;18(1):5. doi: 10.1186/s12970-020-00400-6.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2019
• Primary Completion (Actual): November 30, 2019
• Study Completion (Actual): November 30, 2019

Study Registration Dates

• First Submitted: March 19, 2020
• First Submitted That Met QC Criteria: March 24, 2020
• First Posted (Actual): March 25, 2020

Study Record Updates

• Last Update Posted (Actual): March 25, 2020
• Last Update Submitted That Met QC Criteria: March 24, 2020
• Last Verified: March 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: Nº 507/CEIH/2018

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No