Advanced Search

Study Preview



Study Title and Description

Effects of caffeine on session ratings of perceived exertion.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on behavior*?
  • Comments Comments (
    0
    ) |

Primary Publication Information
  • Comments Comments (
    0
    ) |
TitleData
Title Effects of caffeine on session ratings of perceived exertion.
Author LG Killen,JM Green,EK O'Neal,JR McIntosh,J Hornsby,TE Coates,
Country
Year 2013
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Behavior - Design Details - INCLUDED Studies
Arms
No arms have been defined in this extraction form.

Design Details
Question... Follow Up Answer Follow-up Answer
Refid 22926324
  • Comments Comments (
    0
    ) |
What outcome is being evaluated in this paper? Behavior
  • Comments Comments (
    0
    ) |
What is the objective of the study (as reported by the authors)? The purpose of the current study was to determine the effects of caffeine ingestion (6 mg/kg body weight) on session ratings of perceived exertion (RPE).
  • Comments Comments (
    0
    ) |
Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Participants Fifteen individuals (males: n = 10, females: n = 5) of varying aerobic fitness volunteered as participants. All procedures were approved by the local review board for the protection of human subjects and each participant signed a written informed consent outlining study requirements before initiation of data collection. Participants reported to the lab with instructions to be well rested (C24 h with no heavy physical activity) and well hydrated. Each participant received two 473 mL bottles of water: one to be consumed between dinner and bed the night prior to the trial and the other within an hour of reporting to the lab. Water was administered in attempt to ensure participants reported adequately hydrated in both trials. The caffeine and placebo capsules were administered in sealed containers prior to each trial. Placebo capsules contained maltodextrin and were identical in appearance with the caffeine capsules. Additionally, participants consumed the exact number of capsules for each trial. They were also instructed to avoid alcohol and caffeine (excluding treatment) 4 days (Fisher 1986) prior to each testing session. Each participant completed a survey to determine the amount of caffeine consumed over an average of five days. This information was also used to identify habitual caffeine users. Upon completion of each trial (caffeine and placebo), a questionnaire using a ten-point Likert scale was administered (Hudson et al. 2008). For each question a response of zero indicated the symptom was ‘‘not at all experienced’’ with ten indicating the symptom was ‘‘extremely’’ experienced. The questionnaire was used to determine if the participant experienced any adverse symptoms (fatigue, elevated mood, nervousness, restlessness, tremors, stomach distress) and to what degree the symptoms had been experienced as a result of caffeine consumption. Statistical analysis Means and standard deviations for descriptive characteristics of participants were calculated. Subjective responses from the post-trial questionnaire were compared using a paired t test for each dependent measure. Results were considered significant at p\0.05.
  • Comments Comments (
    0
    ) |
How many outcome-specific endpoints are evaluated? 3
  • Comments Comments (
    0
    ) |
What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) fatigue
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately)
  • Comments Comments (
    0
    ) |
Notes also measured elevated mood, tremors and stomach distress
  • Comments Comments (
    0
    ) |
Clinical
  • Comments Comments (
    0
    ) |
Physiological Physiological
  • Comments Comments (
    0
    ) |
Other
  • Comments Comments (
    0
    ) |
What is the study design? Controlled Trial
  • Comments Comments (
    0
    ) |
Randomized or Non-Randomized? RCT
  • Comments Comments (
    0
    ) |
What were the diagnostics or methods used to measure the outcome? Subjective
  • Comments Comments (
    0
    ) |
Optional: Name of Method or short description Likert scale was administered (Hudson et al. 2008). For each question a response of zero indicated the symptom was ‘‘not at all experienced’’ with ten indicating the symptom was ‘‘extremely’’ experienced. The questionnaire was used to determine if the participant experienced any adverse symptoms (fatigue, elevated mood, nervousness, restlessness, tremors, stomach distress) and to what degree the symptoms had been experienced as a result of caffeine consumption.
  • Comments Comments (
    0
    ) |
Caffeine (general) Caffeine (general)
  • Comments Comments (
    0
    ) |
Coffee
  • Comments Comments (
    0
    ) |
Chocolate
  • Comments Comments (
    0
    ) |
Energy drinks
  • Comments Comments (
    0
    ) |
Gum
  • Comments Comments (
    0
    ) |
Medicine/Supplement
  • Comments Comments (
    0
    ) |
Soda
  • Comments Comments (
    0
    ) |
Tea
  • Comments Comments (
    0
    ) |
Measured Measured
  • Comments Comments (
    0
    ) |
Self-report
  • Comments Comments (
    0
    ) |
Children
  • Comments Comments (
    0
    ) |
Adolescents
  • Comments Comments (
    0
    ) |
Adults Adults
  • Comments Comments (
    0
    ) |
Pregnant Women
  • Comments Comments (
    0
    ) |
What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) placebo (0 mg caffeine) vs 6 mg/kg caffeine
  • Comments Comments (
    0
    ) |
What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) N/A
  • Comments Comments (
    0
    ) |
Provide a general description of results (as reported by the authors). Regarding subjective responses on the post-exercise survey, feelings of fatigue were significantly lower for caffeine (Fig. 6) while nervousness, restlessness, stomach distress, and tremors were significantly higher for caffeine (Fig. 6). Subjective responses for ‘elevated mood’ between caffeine and placebo trials approached but did not reach a priori level of significance for caffeine at p = 0.11.
  • Comments Comments (
    0
    ) |
Did the authors perform a dose-response analysis (or trend/related analysis)? No
  • Comments Comments (
    0
    ) |
What were the authors's observations re: trend analysis?
  • Comments Comments (
    0
    ) |
What were the author's conclusions? Participants reported feeling significantly more nervous and restless while also reporting more tremors and stomach distress (Fig. 6). Hudson et al. (2008) found similar results with participants reporting significant increases in restlessness, tremors, and stomach distress.
  • Comments Comments (
    0
    ) |
What were the sources of funding? None listed.
  • Comments Comments (
    0
    ) |
What conflicts of interest were reported? N/A
  • Comments Comments (
    0
    ) |
Does the exposure (dose) need to be standardized to the SR? Multiple metrics
  • Comments Comments (
    0
    ) |
Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest). mean body weight (as listed by study) = 74 kg 6 mg/kg caffeine = 6 mg/kg * 74 kg = 444 mg caffeine
  • Comments Comments (
    0
    ) |
List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot.  Characterize value as LOAEL/NOAEL, etc. if possible.  nervous - LOAEL = 444 mg/day restless - LOAEL = 444 mg/day fatigue - NOAEL = 444 mg/day
  • Comments Comments (
    0
    ) |
Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. ratings for fatigue improved following caffeine use
  • Comments Comments (
    0
    ) |
What is the importance of the study with respect to the adverseness of the outcome? Important
  • Comments Comments (
    0
    ) |


Baseline Characteristics
No baseline characteristics have been defined for this extraction form.



Results & Comparisons

No Results found.
Adverse Events
Arm or Total Title Description Comments

Quality Dimensions
No quality dimensions were specified.

Quality Rating
No quality rating data was found.