Effects of Caffeine on Cerebral Blood Flow in Clinically Healthy Young People
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 45
- 试验地点
- 2
- 主要终点
- Changes in Mean Velocity (Vocabulary problem)
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
盲法说明
Three groups were randomly constituted, with 15 young people each: control group without caffeine, group with relatively small amount of caffeine (45 mg) administered and group with greater amount of caffeine (120 mg). Participants were not aware to which group they belong.
入排标准
- 年龄范围
- 18 Years 至 30 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •clinically healthy young people
排除标准
- •Individuals with hypertension, high cholesterol, diabetes, arrhythmias, carotid sinus syndrome, severe carotid stenosis and who were in an unstable clinical situation.
结局指标
主要结局
Changes in Mean Velocity (Vocabulary problem)
时间窗: 30 minutes
With solving vocabulary problems, changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Mean Velocity (Hypoventilation)
时间窗: 30 minutes
By performing Hypoventilation, changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Peak systolic velocity (Basal)
时间窗: 30 minutes
Changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Peak systolic velocity (Vocabulary problems)
时间窗: 30 minutes
With solving vocabulary problems, changes in Peak systolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Vend-diastolic velocity (Math problems)
时间窗: 30 minutes
With solving math problems, changes in Vend-diastolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Mean Velocity (Basal)
时间窗: 30 minutes
Changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Mean Velocity (Hyperventilation)
时间窗: 30 minutes
By performing Hyperventilation, changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Mean Velocity (Math problem.)
时间窗: 30 minutes
With solving math problems, changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Peak systolic velocity (Hyperventilation)
时间窗: 30 minutes
By performing Hyperventilation, changes in Peak systolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Vend-diastolic velocity (Vocabulary problems)
时间窗: 30 minutes
With solving vocabulary problems, changes in Vend-diastolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Vend-diastolic velocity (Hypoventilation)
时间窗: 30 minutes
By performing Hypoventilation, changes in Vend-diastolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Vend-diastolic velocity (Short-term memory test)
时间窗: 30 minutes
With short-term memory test, changes in Vend-diastolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Mean Velocity (Short-term memory test)
时间窗: 30 minutes
With short-term memory test, changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Peak systolic velocity (Hypoventilation)
时间窗: 30 minutes
By performing Hypoventilation, changes in Peak systolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Peak systolic velocity (Short-term memory test)
时间窗: 30 minutes
With short-term memory test, changes in Peak systolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Vend-diastolic velocity (Basal)
时间窗: 30 minutes
Changes in Mean Velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Vend-diastolic velocity (Hyperventilation)
时间窗: 30 minutes
By performing Hyperventilation, changes in Vend-diastolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
Changes in Peak systolic velocity (Math problems)
时间窗: 30 minutes
With solving math problems, changes in Peak systolic velocity, measure in m/s from baseline to 30 minutes after caffeine ingestion.
次要结局
- Changes in Heart Rate (Basal)(30 minutes)
- Changes in Heart Rate (Hypoventilation)(30 minutes)
- Changes in Heart Rate (Short-term memory test)(30 minutes)
- Changes in Heart Rate (Hyperventilation)(30 minutes)
- Changes in Heart Rate (Vocabulary problems)(30 minutes)
- Changes in Heart Rate (Math problems)(30 minutes)
研究者
Helder Santos, PhD
Professor
Escola Superior de Tecnologia da Saúde de Coimbra