Effect of a Physical Exercise Session Performed During a 24-34 Hour Fasting Period on Energy Metabolism and Cognitive Function in Healthy Adults (IMS)

December 18, 2025 updated by: Guillermo Sanchez Delgado, Universidad de Granada

Efecto de Una sesión de Ejercicio físico Realizada Durante un Periodo de Ayuno de 24-34 Horas Sobre el Metabolismo energético y la función Cognitiva en Adultos Sanos: Estudio Piloto

This study explores the impact of high-intensity exercise during fasting on energy metabolism and cognitive function in healthy adults. Changes in respiratory exchange ratio, blood substances, and cognitive performance will be measured after 24 and 34 hours of fasting with and without exercise in a randomized crossover design.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
25

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Spain
    • Granada
      • Granada, Granada, Spain, 18007
        • Instiuto Mixto Universitario Deporte y Salud

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • 18-40 years old.
  • Body mass index: 18.5-30.0 Kg/m2.
  • Stable body weight (5kg range within the last 3 months)
  • Being able to consume all the food items provided as part of the study.
  • Not having change the time zone or have shifted sleeping hours equivalent to more than 3 hours on the previous 2 weeks.

Exclusion Criteria:

  • Diagnosed with any chronic condition that, in the research team's opinion or based on the American College of Sports Medicine guidelines, could contraindicate the implementation of 34-hour fasting periods and/or high-intensity exercise.
  • Diagnosed with a chronic endocrine, digestive, rheumatic, neurological, cardiac, pulmonary, autoimmune, or infectious condition that affects energy metabolism.
  • Presenting any signs or symptoms of illness that, in the research team's opinion or based on the American College of Sports Medicine guidelines, could contraindicate the implementation of 34-hour fasting periods and/or high-intensity exercise.
  • Pregnant or breastfeeding.
  • Using medications or supplements that may alter energy metabolism.
  • Currently undergoing or having undergone any type of nutritional intervention or treatment in the past 3 months.
  • Engaging in more than 5 hours per week of habitual moderate-to-vigorous cycling.
  • Any other condition that, in the research team's opinion, discourages participation in the study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Fasting, then fasting+exercise
Behavioral: 34-hour fasting in sedentary conditions
Participants will fast for 34h after a standardized breakfast, refraining from physical activity.
Behavioral: 34-hour fasting with high-intensity exercise
Participants will fast for 34h after a standardized breakfast, performing a high-intensity exercise session 6-10 hours aprox. after starting the fasting period.
Experimental: Fasting + Exercise, then fasting
Behavioral: 34-hour fasting in sedentary conditions
Participants will fast for 34h after a standardized breakfast, refraining from physical activity.
Behavioral: 34-hour fasting with high-intensity exercise
Participants will fast for 34h after a standardized breakfast, performing a high-intensity exercise session 6-10 hours aprox. after starting the fasting period.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Respiratory Exchange Ratio
Time Frame: 24-hour after starting the fasting period
24-hour after starting the fasting period

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Respiratory Exchange Ratio
Time Frame: 34-hour after starting the fasting period
34-hour after starting the fasting period
Serum insulin concentration
Time Frame: 24-hour after starting the fasting period
24-hour after starting the fasting period
Serum insulin concentration
Time Frame: 34-hour after starting the fasting period
34-hour after starting the fasting period
Serum glucose concentration
Time Frame: 24-hour after starting the fasting period
24-hour after starting the fasting period
Serum glucose concentration
Time Frame: 34-hour after starting the fasting period
34-hour after starting the fasting period
Dimensional Change Card Sort Test (NIH toolbox)
Time Frame: 24-hour after starting the fasting period
24-hour after starting the fasting period
Dimensional Change Card Sort Test (NIH toolbox)
Time Frame: 34-hour after starting the fasting period
34-hour after starting the fasting period
List Sorting Working Memory Test (NIH toolbox)
Time Frame: 24-hour after starting the fasting period
24-hour after starting the fasting period
List Sorting Working Memory Test (NIH toolbox)
Time Frame: 34-hour after starting the fasting period
34-hour after starting the fasting period
Flanker Test (NIH toolbox)
Time Frame: 24-hour after starting the fasting period
24-hour after starting the fasting period
Flanker Test (NIH toolbox)
Time Frame: 34-hour after starting the fasting period
34-hour after starting the fasting period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Universidad de Granada

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University Hospital Virgen de las Nieves

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 29, 2023

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 11, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 18, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 5, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 15, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 27, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 26, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 18, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • GSD-2023-002

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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