Clinical trial NCT06737224: The Impact of a 48-hour Fast with or Without Exercise on Immune Cell Metabolism and Glycemic Control in Healthy Active Adults
Official title: The Impact of a 48-hour Fast with or Without Exercise on Immune Cell Function, Bioenergetics, and Glycemic Control in Healthy Active Adults: a Randomized Crossover Trial
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Fasting
Immune Function
Glucose Tolerance
Keywords: Exercise
Immunometabolism
Glycemic control
Lead sponsor: University of British Columbia
Sponsor class: OTHER
First posted: 2024-12-17
Enrollment: 15
Sex: ALL
Minimum age (years): 19
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: Randomized crossover, within-subject, repeated measures
Primary purpose: OTHER

Brief summary: Many individuals engage in fasting for its purported health benefits but the effects of fasting on immune cell and whole body metabolism are not well understood in humans. Moreover, how exercising during a prolonged fast impacts immunometabolic outcomes is unclear. This study will determine how a 2 day fast - performed with or without daily exercise - impacts immune cell bioenergetics, immune cell function, and whole-body glycemic control in healthy active individuals.

Detailed description: Participants will perform two, 48-hour fasts separated by 5 days while wearing a continuous glucose monitor to measure glycemic responses. The order of the trials will be randomized for each participant. The two trials will include an exercise condition (FAST+EX) and a control, non-exercise condition (FAST). During the FAST+EX trial, participants will perform 60 minutes of cycling on each of the two days of the fast. Each bout of exercise will be 60 minutes in duration and consist of 50 minutes of cycling at 60% of predicted heart rate reserve (HRR) followed by 5 x 1-minute intervals at 90% of predicted HRR with 1-minute of passive recovery between each interval. During the FAST trial, participants will be asked to refrain from any structured exercise during the days of the fast. To start the trial, participants will arrive at the lab following an overnight fast. They will consume a standardized meal replacement (Ensure Plus Calories) and blood will be drawn 2 hours post-ingestion. Participants will come to the lab 24 and 48 hours later for subsequent blood draws prior to breaking their fast with the same standardized meal replacement. Another blood sample will be taken 2 hours post-prandial. Participants will be asked to replicate food consumption in each condition for the 24-hour period after they break their fast, and consume the same standardized meal replacement on the morning following the completion of each fast to measure free-living glycemic control 24-hours after a fast performed with or without exercise. There will be a five-day wash out period in between the completion of both trials for all participants.

Eligibility criteria: Inclusion Criteria:

* Aged between 19 and 35 years.
* Physically active (engaging in ≥150 minutes of weekly moderate to vigorous physical activity).

Exclusion Criteria:

* History of cardiometabolic diseases or inflammatory diseases (e.g., chronic obstructive pulmonary disease (COPD), rheumatoid arthritis, cardiovascular disease).
* Individuals currently following a ketogenic diet, low-calorie diet, periodic fasting regimen, or consuming ketogenic supplements (e.g., exogenous ketone drinks).
* Cigarette/vaping smoking.
* Physical limitation that will impair the ability of the participant to perform exercise.
* Individuals having a body mass index (BMI) over 30 kg/m2.
* Cancer diagnosis in the past 5 years.
* Taking anti-inflammatory drugs (e.g., ibuprofen, aspirin, naproxen).
* Being unable to read or communicate in English.

Primary outcomes:
measure: Monocyte mitochondrial respiration
timeFrame: Baseline and 48 hours
Secondary outcomes:
measure: Alteration in immune cell functions
timeFrame: Baseline and 48 hours
measure: Change in glucose tolerance
timeFrame: Baseline, after 48 hours of fasting, and 24 hours after breaking the fast in free-living condition)
measure: Blood pressure
timeFrame: Baseline, 24 hours into the fast, and at the end of the fast (48 hours)
measure: Rate and level of ketosis
timeFrame: Baseline, 24 hours and 48 hours during fasting
measure: Compensatory movement behaviour
timeFrame: During and 48 hours after the fast
measure: Hunger sensation
timeFrame: At baseline, 12:00, 18:00 during the first and second day of the fast.
measure: Sleep quality
timeFrame: Baseline the morning before starting the fast, after 24 hours of fasting, and again after 48 hours of fasting.
measure: Affect during exercise
timeFrame: Before, during (e.g., at 10, 20, 30, 40, and 50 minutes as well as during intervals 1,2,3,4, and 5 at the end of the intervals as well as during the passive recovery) and following the two exercises conditions (post 5 minutes in a seated position).
measure: Remembered Enjoyment
timeFrame: 10 minutes after each exercise session.
measure: Rate of perceived exertion
timeFrame: During both exercise sessions at 10, 20, 30, 40, and 50 minutes as well as during intervals 1, 2, 3, 4, and 5 at the end of the intervals.
measure: Glucose homeostasis
timeFrame: During and 24 hours after both condition
Other outcomes:
Locations:
city: Kelowna
country: Canada
facility: University of British Columbia Okanagan Campus
state: British Columbia
Study officials:
References: