Clinical trial NCT05866848: Effects of Caffeine on Cerebral Blood Flow
Official title: Effects of Caffeine on Cerebral Blood Flow in Clinically Healthy Young People
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Cardiovascular System
Keywords: Transcranial Doppler ultrasonography
Middle Cerebral Artery
functional tests
cognitive activities
caffeine
Lead sponsor: Escola Superior de Tecnologia da Saúde de Coimbra
Sponsor class: OTHER
First posted: 2023-05-19
Enrollment: 45
Sex: ALL
Minimum age (years): 18
Maximum age (years): 30
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: All subjects were submitted to 2 evaluation moments: the first baseline moment and the second moment, 30 minutes after caffeine ingestion, which constitutes the time required for caffeine absorption.

In each of the 2 moments, they performed 30 seconds of continuous breathing (hypoventilation), followed by 30 seconds of continuous rapid breathing (hyperventilation). VMCA measurements were stabilized between these tests. The study started with apnea testing because VMCA requires less time to return to baseline levels after hypoventilation than after hyperventilation.

When VMCA measurements were stable, a 30-second baseline period was followed by three 30-second cognitive tasks, with a 1-minute break between activities: short-term memory test; solve a vocabulary problem; and solving a math problem. Three versions of each cognitive task were used for the three conditions. The procedure was completed with a final rest period of 60 seconds.
Primary purpose: BASIC_SCIENCE

Brief summary: The goal of this clinical trial is to evaluate in clinically healthy young people if:

* after caffeine ingestion, there are variations in blood velocity of the middle cerebral arteries (VMCA),
* this variation is dependent on the administered dose.

Transcranial Doppler ultrasonography was used to record blood VMCA in three groups of 15 clinically healthy young adults each - no caffeine, low caffeine (45 mg) and high caffeine group (120 mg). Transcranial Doppler ultrasonography provided simultaneous bilateral VMCA measurements while subjects performed functional tests (hyperventilation and hypoventilation orders) and three cognitive activities (Test 1, short-term remembering, Test 2, solving a vocabulary problem, and Test 3, solving a math problem) each in 31-second tests with 1-minute rest between them. Participants were assessed before and 30 minutes after caffeine ingestion.

Detailed description: Were used in the study, Capsules dosed with 45mg and 120 mg of anhydrous caffeine and flour capsules as a placebo. In the preparation of the capsules, a semi-automatic capsulator No. 0 (Capsunorm® by Tecnyfarma®) were used, colorless hard gelatin capsules No. 0 by Acopharma® and anhydrous caffeine (Biochem®, C.A.S. 58-08-2).

Viasys Sonara transcranial Doppler unit and a 2 MHz probe were used to sample the middle cerebral artery at depths of 60 millimeters, using emission doppler pulsed performing spectral analysis in real time. Two probes (bilaterally) of 2MHz were placed at a depth between 55 and 60 mm, thus making it possible to analyse both middle cerebral arteries simultaneously.

Each participant was asked not to ingest caffeine and exercise vigorously for at least 12 hours before the assessment. In the case of smokers, they were also asked not to smoke for at least 2 hours before the evaluation. The laboratory had medium luminosity, silent and controlled temperature (23º/24ºC). To avoid inter-observer errors, all examinations were performed by the same investigator who was not aware of what dose was/had been administered to the participant.

Subjects were tested while seated in a reclining chair located in a dimly lit, sound-attenuated room and performed the activities with their eyes closed.

Eligibility criteria: Inclusion Criteria:

* clinically healthy young people

Exclusion Criteria:

* Individuals with hypertension, high cholesterol, diabetes, arrhythmias, carotid sinus syndrome, severe carotid stenosis and who were in an unstable clinical situation.

Primary outcomes:
measure: Changes in Mean Velocity (Basal)
timeFrame: 30 minutes
measure: Changes in Mean Velocity (Hypoventilation)
timeFrame: 30 minutes
measure: Changes in Mean Velocity (Hyperventilation)
timeFrame: 30 minutes
measure: Changes in Mean Velocity (Short-term memory test)
timeFrame: 30 minutes
measure: Changes in Mean Velocity (Vocabulary problem)
timeFrame: 30 minutes
measure: Changes in Mean Velocity (Math problem.)
timeFrame: 30 minutes
measure: Changes in Peak systolic velocity (Basal)
timeFrame: 30 minutes
measure: Changes in Peak systolic velocity (Hypoventilation)
timeFrame: 30 minutes
measure: Changes in Peak systolic velocity (Hyperventilation)
timeFrame: 30 minutes
measure: Changes in Peak systolic velocity (Short-term memory test)
timeFrame: 30 minutes
measure: Changes in Peak systolic velocity (Vocabulary problems)
timeFrame: 30 minutes
measure: Changes in Peak systolic velocity (Math problems)
timeFrame: 30 minutes
measure: Changes in Vend-diastolic velocity (Basal)
timeFrame: 30 minutes
measure: Changes in Vend-diastolic velocity (Hypoventilation)
timeFrame: 30 minutes
measure: Changes in Vend-diastolic velocity (Hyperventilation)
timeFrame: 30 minutes
measure: Changes in Vend-diastolic velocity (Short-term memory test)
timeFrame: 30 minutes
measure: Changes in Vend-diastolic velocity (Vocabulary problems)
timeFrame: 30 minutes
measure: Changes in Vend-diastolic velocity (Math problems)
timeFrame: 30 minutes
Secondary outcomes:
measure: Changes in Heart Rate (Basal)
timeFrame: 30 minutes
measure: Changes in Heart Rate (Hypoventilation)
timeFrame: 30 minutes
measure: Changes in Heart Rate (Hyperventilation)
timeFrame: 30 minutes
measure: Changes in Heart Rate (Short-term memory test)
timeFrame: 30 minutes
measure: Changes in Heart Rate (Vocabulary problems)
timeFrame: 30 minutes
measure: Changes in Heart Rate (Math problems)
timeFrame: 30 minutes
Other outcomes:
Locations:
city: Coimbra
country: Portugal
facility: Coimbra Health School
Study officials:
affiliation: Polytechnic Institute of Coimbra - Coimbra Health School
name: Hélder Santos, PhD
role: PRINCIPAL_INVESTIGATOR
References: