Influence of the Time of Day in the Effect of Caffeine on Maximal Fat Oxidation During Exercise in Women (CIRCAF_WOM)

Influence of the Time of Day in the Effect of Caffeine on Maximal Fat Oxidation During Exercise in Women. A Randomized, Crossover, Double-blind, and Placebo-controlled Study

Caffeine is a natural stimulant with well-recognized metabolic benefits, however, there is a lack of studies investigating the time-of-day caffeine influence to enhance fat oxidation in women. The aim of this study was to evaluate the influence of the time of the day on the effect of caffeine on maximal rate of fat oxidation during aerobic exercise in women.

Study Overview

• Status: Completed
• Conditions: Dietary Supplement
• Intervention / Treatment: Dietary supplement: Acute caffeine supplementation

Detailed Description

Caffeine is a natural stimulant with well-recognized sports performance benefits. Aside its performance-enhancing effect, caffeine has the potential of increasing fat utilization during aerobic exercise at submaximal intensities, lowering-down the contribution of carbohydrate as a fuel. This property of caffeine may provoke a glycogen-sparing effect in the skeletal muscle and liver for exercise situations where carbohydrate availability may be a challenge. Additionally, the capacity of caffeine to enhance fat utilization during exercise could be of interest for improving health outcomes as it may increase the rate of change in body composition in exercise programs. Maximal fat oxidation rate (MFO) during exercise is a remarkable physiological indicator associated with metabolic flexibility/body weight loss and endurance performance To date, it is unknown if caffeine increases MFO in the same proportion during morning and evening exercise trials in women. For this reason, the aim of the present study was to evaluate the influence of the time of the day on the effect of caffeine on MFO in women. We hypothesised that caffeine would increase MFO during morning and evening exercise and this effect would be of similar magnitude at both times of day.

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Madrid
    • Pozuelo De Alarcón, Madrid, Spain, 28223
      • Universidad Francisco de Vitoria

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• To be non-smokers.
• To have low caffeine intake (i.e., < 50 mg of caffeine per day in the previous 2 months)
• To show no previous history of cardiopulmonary diseases or having suffered musculoskeletal injuries in the previous 6 months.
• To have a regular duration of their menstrual cycle for the previous 6 months.
• To confirm no existence of any type of menstrual disorders such as dysmenorrhea, amenorrhea, or strong symptoms associated with pre-menstrual syndrome.

Exclusion Criteria:

-

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Caffeine intake; Test in the morning A dose of 3 mg/kg of caffeine (Bulk Powders, Essex, United Kingdom) was ingested before the beginning of each test. Test in the evening A dose of 3 mg/kg of caffeine (Bulk Powders, Essex, United Kingdom) was ingested before the beginning of each test.	Dietary supplement: Acute caffeine supplementation; To evaluate the influence of the time of the day (i.e., morning vs evening) on the effect of caffeine on maximal fat oxidation in women.
Placebo Comparator: Placebo intake; Test in the morning A dose of 3 mg/kg of placebo (Cellulose, Guinama, Valencia, Spain) was ingested before the beginning of each test. Test in the evening A dose of 3 mg/kg of placebo (Cellulose, Guinama, Valencia, Spain) was ingested before the beginning of each test	Dietary supplement: Acute caffeine supplementation; To evaluate the influence of the time of the day (i.e., morning vs evening) on the effect of caffeine on maximal fat oxidation in women.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
MFO	Maximal fat oxidation during exercise	2-months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
FATmax	The intensity of exercise that elicits MFO	2-months
RPE	Rate of percevied exertion during exercise	2-months
FAT AND CHO oxidation	Fat and carbohydrates oxidation	2-months

Collaborators and Investigators

• Sponsor: Universidad Francisco de Vitoria
• Collaborators: Universidad de Granada; Universidad Rey Juan Carlos; Camilo Jose Cela University

Study record dates

Study Major Dates

• Study Start (Actual): February 9, 2021
• Primary Completion (Actual): April 9, 2021
• Study Completion (Actual): April 9, 2021

Study Registration Dates

• First Submitted: May 18, 2023
• First Submitted That Met QC Criteria: May 18, 2023
• First Posted (Actual): May 30, 2023

Study Record Updates

• Last Update Posted (Actual): May 30, 2023
• Last Update Submitted That Met QC Criteria: May 18, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Purinergic Antagonists; Purinergic Agents; Phosphodiesterase Inhibitors; Purinergic P1 Receptor Antagonists; Central Nervous System Stimulants; Caffeine
• Other Study ID Numbers: UFVitoria_2

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