Caffeine, Placebo - Control, No Pill
Conditions
Keywords
Caffine, morning cognitive performance, morning repeated sprint performance
Brief summary
Athletes often compete in the morning when they are biologically weaker; normally in competition heats or quarterfinals to qualify for the finals scheduled in the evening. Some athletes may even choose to perform at submaximal levels in these qualifying rounds, especially when they are expected to perform multiple times in the same day (such as weightlifting at the Olympic Games). Gross muscular performance such as power output or force production is greater in the evening than the morning (\ 3-14% variation). Similarly, time-trial performance and repeated sprint performance (RSP; a good measure of performance in team sport) is \ 3 and 5 % greater in the evening than the morning. The reason for this daily variation in performance is attributed to central factors (such as the body clock), as well as motivational and peripheral factors, including higher core and muscle temperatures in the evening compared to the morning. The body clock located within the anterior hypothalamus consists of a group of neurons known as suprachiasmatic nuclei, which are responsible for controlling the rhythm of core temperature. This 'master clock' has an endogenous period (\ 24.2 h) slightly longer than the 24-h solar day; therefore, must be entrained by time cues (zeitgebers) to remain in sync with the environment, of these the light-dark cycle is the most powerful in humans. The most efficient nutritional ergogenic is caffeine. Recently caffeine has been investigated to reduce the negative influence of diurnal variations on repeated-sprint ability test (10 × 6 s cycle sprints, with 30 s of rest) at 60 min after ingestion of either 5 mg·kg-1 or placebo. A recent study reported that caffeine supplementation did not prevent the reduction in performance in the morning. However, placebo effect can be 3-5% and hence the use of a No-pill condition would ensure that any placebo effect is accounted for and that the true potential effect of caffeine can be established. To the best of our knowledge, no study has yet investigated a) caffeine (300 mg), NoPill or Placebo (300 mg dextrose) effects on cognitive and physiological morning performance.
Interventions
Sponsors
Liverpool John Moores University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)
Masking description
Both researcher and participants did not know what of the two pill options were caffeine
Intervention model description
Double blinded counterbalanced design with three conditions
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy adults * 18-35 years old * Injury-free * ≥ 2 years of weight/strength training experience * Not receiving any pharmacological treatment (including non-steroidal anti-inflammatory drugs, NSAIDs) throughout the study period * Low habitual caffeine consumers (≤ 150mg per day) * No preference to training regarding time-of-day
Exclusion criteria
* Depressed mood (from the Beck depression inventory) * Poor sleep quality (a Pittsburgh sleep quality index global score \>5 * Recent shift work or travel across multiple time-zones * 'Extreme' chronotype (assessed via the Composite Morningness Questionnaire * Risk factors and/or symptoms of cardiovascular disease. * Page 9 of 11 - • Minimal knowledge of the effects of time-of-day or time-since-sleep on human performance
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Morning repeated sprint performance test | From enrolment to last experimental session (~4 weeks) | Morning repeated sprint performance test (10 x 20 m with 30 s recovery) on a vulcanised surfaced runway. With time recorded at 5, 10, 15 and 20 m in seconds. |
| Morning repeated sprint performance test heart rate | From familiarisation to the final experimental session (~4 weeks). | Morning repeated sprint performance test (10 x 20 m with 30 s recovery) on a vulcanised surfaced runway. With heart rate using a heart rate monitor recorded at the end of each sprint. Takes \~ 1 second. |
| Rating of perceived exertion every sprint | From familiarisation to the final experimental session (~4 weeks) | Morning repeated sprint performance test (10 x 20 m with 30 s recovery) on a vulcanised surfaced runway. With ratine of perceived exertion recorded at the end of each sprint. Takes \~ 1 second. Measured on a 6 (no exertion) to 20 (maximal exertion) scale. |
| Blood lactate and glucose at the end of the 10 sprints | From enrolment to last experimental session (4 weeks) | Blood taken from the finger tip and analysed for lactate and glucose levels in mmols. Takes 10 s. |
| Core body temperature | From enrolment to last experimental session (4 weeks) | Ear temperature taken at rest and after the warmup. Measured in degrees Celsius. Takes 3 seconds. |
| Morning Rey Auditory Verbal Learning Test | From familiarisation to the final experimental session (~4 weeks) | Rey Auditory Verbal Learning Test: The RAVLT is a neuropsychological assessment designed to evaluate verbal memory. The test is designed as a list-learning paradigm in which the volunteer hears a list of 15 nouns and is asked to recall as many words from the list as possible. The number correct and the number that were given by the participant but not on the list (intrusions) are noted. This process is re-peated 4 more times. The process is repeated but with a second interference list (List B) is presented in the same manner, and the participant is asked to recall as many words as possible from List B and scoring recorded. . After the interference trial, the participant is immediately asked to recall the words from List A, which they heard five times previously and the number of correct words and intrusions are recorded. RAVTL total number, number of dis-tractions and retention are recorded and analysed. |
| Morning Stroop word-colour interference test | From familiarisation to the final experimental session (~4 weeks) | Stroop word-colour interference test. The participants were asked to read out their responses to words or colours for 45 s as quickly as possible and to leave no errors uncorrected. This was filmed and the number of errors and total amount completed was recorded and analysed. The first sheet had text (red, blue, yellow, black and green) in black ink (naming word test, W). The second sheet had blocks of colour corresponding to the text on the first sheet (naming colour test, C). With the third sheet, the participants had to read out the word (which was coloured differently to the word, e.g., the word was yellow and the colour red, referred to as the naming colour of word test, CW) and for the fourth sheet, the participants had to read out the colon (which was wrongly named, e.g., the colour was yellow but the word was red, referred to as the naming of word not colour test, WC). In this fourth sheet, the words were printed in the reverse order to the third sheet. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Morning grip strength | Time Frame: From enrolment to last experimental session (4 weeks) | Morning grip strength assessed from left and right grip strength on a dynamometer (kg). Takes 4 minutes. |
| Vertical jump (Counter movement Jump and hands on hips - best of 3) | From enrolment to last experimental session (4 weeks)] | Vertical jump height test (with hands on hips and countermovement jump to measure flight time and height reached; Optojump Next, Microgate, UK. For jump tests variables will be collected on a laptop with associated software (Optojump Next, Microgate, UK). Measured in cm of height. |
| Witty Cognitive agility test 2x 90 s | From enrolment to last experimental session (4 weeks)] | Performing Witty cognitive agility test (90 s responding to 6 lights on a metal frame where some are at waist level, some shoulder and some at head height at various distances from the volunteer). After each response the participant retreats behind a 1 m line back to starting position (Witty SEM system, Microgate, UK) - test done two times. Each light blocked and the light on the frame was recorded. From far left to far right the lights were numbered 1 to 5 and time was measured in milli seconds. |
| Morning Trail Making Test time to completion in seconds (TMT; parts A and B) | From enrolment to last experimental session (4 weeks) | To assess the effect of 300 mg caffeine (CAFF) vs placebo (PLAC) vs no-pill (NoPill) on morning Trail Making Test time to completion in seconds (TMT; parts A and B). In part A the circles are numbered 1-25, and the participant is instructed to draw lines to connect the numbers in ascending order. In part B, the circles include both numbers (1-13) and letters (A-L) and the participant is instructed to draw lines to connect the circles in ascending pattern but with the added task of alternating between numbers and letters (i.e., 1-A-2-B-3-C etc.). In both parts the participant is instructed to connect to the circles as fast as possible, without lifting the pencil from the paper. If an error is made, this is pointed out immediately and the participant is allowed to correct it. During the test, time to completion is measured, with a higher time indicative of the greater impairment. |
| Morning profile of mood states questionnaire | From familiarisation to the final experimental session (~4 weeks) | Morning profile of mood states questionnaire (POMS; Version 32) for moods: vigour, tension, calmness, happiness, confusion, depression and fatigue on a visual analogue scale (0=not at all and 4 = extremely). Each mood is the addition of scores for the 4 questions associated with the mood. \~ 60 s each task. |
| Sleep questions from the Liverpool Jet lag Questionnaire | From familiarisation to the final experimental session (~4 weeks) | Sleep questions from the Liverpool Jet lag Questionnaire: get to sleep, how well slept, waking time and alertness after waking. Measured on a -5 (later or worst) to +5 scale (more or earlier) where ZERO is compared to normal. |
| 7-day food diary | Baseline | 7-day food diary that was analysed using Nutritics® analysis software by a SENr registered Sports and Exercise Nutritionist. Data is presented in macro-nutrients and micro-nutrient diet (mg or g). |
| Habitual caffeine consumption | Baseline | Habitual caffeine consumption was assessed using the caffeine consumption questionnaire (CCQ), where caffeine intake was assessed in the morning, afternoon, evening and night. Total daily intake was expressed in mg. |
| Self-reported 2-week training diary | 2 weeks before the main experiment | No preference to training regarding time-of-day by a weekly self-reported 2-week training diary for type of exercise, duration, intensity and time of day. With time of day of exercise preference recorded. |
| Chronotype | Baseline | Extreme chronotype (assessed via the Composite Morningness Questionnaire) to assess morning, intermediate and evening types. Where Evening type scores 22 and less, Intermediate type 22-43 and Morning type 44 and above. |
| Poor sleep quality | Baseline | Poor sleep quality (as indicated by the Pittsburgh sleep quality index global score \>5). |
| Depressed mood | Baseline | Depressed mood severity from the Beck depression inventory (BDI).21 questions were answered (with 4 answers, 0 = I do not feel and 3 = I am so..). The values summated to scores where 0-9 is minimal depression, 10-18 mild and 19-29 moderate depression. 30-63 sever depression. This takes 60 s to complete. |
| Caffeine withdrawal symptoms score | From familiarisation to the final experimental session (~4 weeks). | Caffeine withdrawal symptoms (total score) assesses caffeine withdrawal symptoms. Participants were asked to rate each of the 32 questions in terms of how they were feeling at that moment on a 5-pt. scale from 0 (not at all) to 4 (extremely). Eight of the items are positively worded (e.g., energetic) and were reversed scored prior to analyses. At start and during the protocol. |
Countries
United Kingdom
Contacts
PRINCIPAL_INVESTIGATORBen J Edwards, PHD
Liverpool John Moores University
Outcome results
None listed