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

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: Completed
• Conditions: Energy Metabolism
• Intervention / Treatment: Behavioral: 34-hour fasting in sedentary conditions; Behavioral: 34-hour fasting with high-intensity exercise

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Time Frame
Respiratory Exchange Ratio	24-hour after starting the fasting period

Secondary Outcome Measures

Outcome Measure	Time Frame
Respiratory Exchange Ratio	34-hour after starting the fasting period
Serum insulin concentration	24-hour after starting the fasting period
Serum insulin concentration	34-hour after starting the fasting period
Serum glucose concentration	24-hour after starting the fasting period
Serum glucose concentration	34-hour after starting the fasting period
Dimensional Change Card Sort Test (NIH toolbox)	24-hour after starting the fasting period
Dimensional Change Card Sort Test (NIH toolbox)	34-hour after starting the fasting period
List Sorting Working Memory Test (NIH toolbox)	24-hour after starting the fasting period
List Sorting Working Memory Test (NIH toolbox)	34-hour after starting the fasting period
Flanker Test (NIH toolbox)	24-hour after starting the fasting period
Flanker Test (NIH toolbox)	34-hour after starting the fasting period

Collaborators and Investigators

• Sponsor: Universidad de Granada
• Collaborators: University Hospital Virgen de las Nieves

Study record dates

Study Major Dates

• Study Start (Actual): May 29, 2023
• Primary Completion (Actual): June 11, 2025
• Study Completion (Actual): June 18, 2025

Study Registration Dates

• First Submitted: June 5, 2023
• First Submitted That Met QC Criteria: June 15, 2023
• First Posted (Actual): June 27, 2023

Study Record Updates

• Last Update Posted (Actual): December 26, 2025
• Last Update Submitted That Met QC Criteria: December 18, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Other Study ID 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