Impact of Caffeine Intake on Autonomic Parameters in the Exercise of Strength
Condition: Autonomic Nervous System; Cardiovascular Outcomes
Study type: Interventional

Summary: 
      The objective of this study was to evaluate the variability of the heart rate of exercise
      physicists with and without caffeine intake. Practitioners of resisted physical exercise,
      specifically bodybuilding, who are young adults between the ages of 18 and 30 will
      participate in the study. To define the sample size, a sample calculation was performed based
      considering as variable the RMSSD index (square root of the square mean of the differences
      between the adjacent normal iRRs). The significant difference magnitude assumed was 12 ms,
      considering a standard deviation of 16.2 ms, with alpha risk of 5% and beta of 80%. A minimum
      of 14 subjects per group were required in the survey. A total of 32 subjects will participate
      in the research, being these divided and allocated in different groups. Sampling will be of
      the intentional kind.
    

Detailed description: 
      Caffeine supplementation has been studied in several sports modalities with the objective of
      investigating its repercussions on athletes' physical performance. Caffeine may lead to an
      obstruction of adenosine receptors (A1 and A2) and increase the activity of the Autonomic
      Nervous System (ANS) by releasing catecholamines in plasma, inducing tachycardia and
      elevating blood pressure. Such modulation of nervous system activity can be traced by
      assessing heart rate variability (HRV). HRV is one of the most practical methods to analyze
      the physiological functioning of ANS, both in pathological conditions of the individual and
      in the induction of other variables, being a noninvasive measure of cardiac autonomic
      modulation markers that analyzes the peak-R intervals a peak-R (RRI) of consecutive
      heartbeat. The objective of this study was to evaluate the variability of the heart rate of
      exercise physicists with and without caffeine intake. Practitioners of resisted physical
      exercise, specifically bodybuilding, who are young adults between the ages of 18 and 30 will
      participate in the study. To define the sample size, a sample calculation was performed based
      considering as variable the RMSSD index (square root of the square mean of the differences
      between the adjacent normal iRRs). The significant difference magnitude assumed was 12 ms,
      considering a standard deviation of 16.2 ms, with alpha risk of 5% and beta of 80%. A minimum
      of 14 subjects per group were required in the survey. A total of 32 subjects will participate
      in the research, being these divided and allocated in different groups. Sampling will be of
      the intentional kind.

      The expected benefits with the result of this research are to instigate the creation of new
      lines of research in this context, being able to intervene in a more effective way in
      practitioners of physical exercise of strength, with the possibility of prevention to the
      autonomic alterations that are associated with the consumption of stimulant supplements, such
      as caffeine, and its consequences on the cardiovascular system.
    

Intervention name(s): Placebo; Caffeine
Intervention type(s): Dietary Supplement; Other
Intervention description(s): On the first day of collection, the volunteers will not take placebo intake, the data will be collected in a standardized way, respecting the times defined for the analysis of the cardiac activity. Then the collection will be continued. On the next day of evaluation, volunteers will receive a capsule containing 300 mg of placebo and will be advised to consume 1 hour before the procedure.; On the first day of collection, the volunteers will not take caffeine intake, the data will be collected in a standardized way, respecting the times defined for the analysis of the cardiac activity. Then the collection will be continued. On the next day of evaluation, volunteers will receive a capsule containing 300 mg of caffeine and will be advised to consume 1 hour before the procedure.
Intervention MeSH terms: Caffeine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: It is a randomized, single-blind clinical trial
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: Caffeine; Exercise; Heart Rate Variability; Autonomic Nervous System; Cardiovascular Risk Factor