CaffeineEarly Phase 1NCT07466732
Effects of Caffeine Ingestion on Morning Cognitive and Muscle Repeated Sprint Performance in Males
A Early Phase 1 study testing Caffeine, Placabo and No Pill in people with Caffeine and Placebo - Control, run by Liverpool John Moores University at 1 site in United Kingdom.
Trial 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… Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Caffeine, Placebo - Control, No Pill
- What is being tested?
- Caffeine, Placabo and No Pill
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 8 Dec 2025to 25 Mar 2026
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site
Tom Reilly Building (LJMU)
Liverpool, Merseyside, L3 3AF
About this study
Official title: Effects of Caffeine Ingestion on Morning Cognitive and Muscle Repeated Sprint Performance in Males. Where a Standardized Approach Has Been Employed
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.
Read more
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.
- Conditions
- Caffeine, Placebo - Control, No Pill
- Being tested
- Caffeine, Placabo, No Pill
- Keywords
- Caffine, morning cognitive performance, morning repeated sprint performance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CaffeineDrug
300mg of of caffeine anhydrous in 3 capsules similar to PLACEBO in size and weight
PlacaboOther
3 capsules of PLACEBO similar to caffeine condition in size and weight
No PillOther
No capsules were given
| Study group | Role | What they receive |
|---|---|---|
| Group 1 | Experimental | 1) NoPill, 2) PLAC, 3) Caffeine (300 mg) Receives: Drug: Caffeine; Other: Placabo; Other: No Pill |
| Group 2 | Experimental | 1) PLAC, 22) Caffeine (300 mg) 3) NoPill Receives: Drug: Caffeine; Other: Placabo; Other: No Pill |
| Group 3 | Experimental | 1) Caffeine (300 mg) 2) NoPill, 3) PLAC Receives: Drug: Caffeine; Other: Placabo; Other: No Pill |
What is being measured
The primary outcome is the main question the study is designed to answer.
Morning repeated sprint performance test
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.
Measured: From enrolment to last experimental session (~4 weeks)
Morning repeated sprint performance test heart rate
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.
Measured: From familiarisation to the final experimental session (~4 weeks).
Rating of perceived exertion every sprint
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.
Measured: From familiarisation to the final experimental session (~4 weeks)
Blood lactate and glucose at the end of the 10 sprints
Blood taken from the finger tip and analysed for lactate and glucose levels in mmols. Takes 10 s.
Measured: From enrolment to last experimental session (4 weeks)
Core body temperature
Ear temperature taken at rest and after the warmup. Measured in degrees Celsius. Takes 3 seconds.
Measured: From enrolment to last experimental session (4 weeks)
Morning Rey Auditory Verbal Learning Test
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.
Measured: From familiarisation to the final experimental session (~4 weeks)
Morning Stroop word-colour interference test
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.
Measured: From familiarisation to the final experimental session (~4 weeks)
Secondary outcomes (13)
Morning grip strength
Morning grip strength assessed from left and right grip strength on a dynamometer (kg). Takes 4 minutes.
Measured: Time Frame: From enrolment to last experimental session (4 weeks)
Vertical jump (Counter movement Jump and hands on hips - best of 3)
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.
Measured: From enrolment to last experimental session (4 weeks)]
Witty Cognitive agility test 2x 90 s
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.
Measured: From enrolment to last experimental session (4 weeks)]
Morning Trail Making Test time to completion in seconds (TMT; parts A and B)
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.
Measured: From enrolment to last experimental session (4 weeks)
Morning profile of mood states questionnaire
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.
Measured: From familiarisation to the final experimental session (~4 weeks)
Sleep questions from the Liverpool Jet lag Questionnaire
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.
Measured: From familiarisation to the final experimental session (~4 weeks)
7-day food diary
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).
Measured: Baseline
Habitual caffeine consumption
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.
Measured: Baseline
Self-reported 2-week training diary
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.
Measured: 2 weeks before the main experiment
Chronotype
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.
Measured: Baseline
Poor sleep quality
Poor sleep quality (as indicated by the Pittsburgh sleep quality index global score >5).
Measured: Baseline
Depressed mood
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.
Measured: Baseline
Caffeine withdrawal symptoms score
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.
Measured: From familiarisation to the final experimental session (~4 weeks).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Mar 2026
- Study start8 Dec 2025
- Primary completion25 Mar 2026 (estimated)
- Study completion25 Mar 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for CaffeineStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Double blinded counterbalanced design with three conditions
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 15 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Liverpool John Moores University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ben J. Edwards, PhD, Liverpool John Moores University
- Investigators
- Ben J Edwards, PHD, Principal investigator, Liverpool John Moores University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07466732
- Sponsor's protocol ID
- 251127LJMUSPSREC93
- Status last verified
- Mar 2026
- First submitted
- 25 Feb 2026
- Last updated
- 13 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: IPD unavailable due to privacy or ethical restrictions
Publications
Walsh NP, Halson SL, Sargent C, Roach GD, Nedelec M, Gupta L, Leeder J, Fullagar HH, Coutts AJ, Edwards BJ, Pullinger SA, Robertson CM, Burniston JG, Lastella M, Le Meur Y, Hausswirth C, Bender AM, Grandner MA, Samuels CH. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med. 2020 Nov 3:bjsports-2020-102025. doi: 10.1136/bjsports-2020-102025. Online ahead of print.
PubMed 33144349Drust B, Waterhouse J, Atkinson G, Edwards B, Reilly T. Circadian rhythms in sports performance--an update. Chronobiol Int. 2005;22(1):21-44. doi: 10.1081/cbi-200041039.
PubMed 15865319Munnilari M, Bommasamudram T, Easow J, Tod D, Varamenti E, Edwards BJ, Ravindrakumar A, Gallagher C, Pullinger SA. Diurnal variation in variables related to cognitive performance: a systematic review. Sleep Breath. 2024 Mar;28(1):495-510. doi: 10.1007/s11325-023-02895-0. Epub 2023 Aug 17.
PubMed 37589927Mitchell PJ, Redman JR. Effects of caffeine, time of day and user history on study-related performance. Psychopharmacology (Berl). 1992;109(1-2):121-6. doi: 10.1007/BF02245489.
PubMed 1365645
Study at a glance
From the registry record, last updated by the sponsor on 13 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Caffeine Ingestion on Morning Cognitive and Muscle Repeated Sprint Performance in Males. Where a Standardized Approach Has Been Employed
- ClinicalTrials.gov ID
- NCT07466732
- Acronym / sponsor ID
- 251127LJMUSPSREC93
- Conditions
- Caffeine, Placebo - Control, No Pill
- Keywords
- Caffine, morning cognitive performance, morning repeated sprint performance
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 15 participants (estimated)
- Lead sponsor
- Liverpool John Moores UniversityUniversity, hospital or other
- Study start
- 8 Dec 2025 (actual)
- Primary completion
- 25 Mar 2026 (estimated)
- Study completion
- 25 Mar 2026 (estimated)
- First posted
- 12 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
- Model description
- Double blinded counterbalanced design with three conditions
| Arm | Type | Receives |
|---|---|---|
| Group 1 | Experimental | Drug: Caffeine, Other: Placabo, Other: No Pill1) NoPill, 2) PLAC, 3) Caffeine (300 mg) |
| Group 2 | Experimental | Drug: Caffeine, Other: Placabo, Other: No Pill1) PLAC, 22) Caffeine (300 mg) 3) NoPill |
| Group 3 | Experimental | Drug: Caffeine, Other: Placabo, Other: No Pill1) Caffeine (300 mg) 2) NoPill, 3) PLAC |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (6 listed)
- Depressed mood (from the Beck depression inventory)
- Page 9 of 11 - • Minimal knowledge of the effects of time-of-day or time-since-sleep on human performance
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Caffeine300mg of of caffeine anhydrous in 3 capsules similar to PLACEBO in size and weight | Drug | Group 1, Group 2, Group 3 |
| Placabo3 capsules of PLACEBO similar to caffeine condition in size and weight | Other | Group 1, Group 2, Group 3 |
| No PillNo capsules were given | Other | Group 1, Group 2, Group 3 |
Primary outcome
Morning repeated sprint performance test
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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.
13 secondary outcomes
Morning grip strength
Time frame: Time Frame: From enrolment to last experimental session (4 weeks)
Vertical jump (Counter movement Jump and hands on hips - best of 3)
Time frame: From enrolment to last experimental session (4 weeks)]
Witty Cognitive agility test 2x 90 s
Time frame: From enrolment to last experimental session (4 weeks)]
Morning Trail Making Test time to completion in seconds (TMT; parts A and B)
Time frame: From enrolment to last experimental session (4 weeks)
Morning profile of mood states questionnaire
Time frame: From familiarisation to the final experimental session (~4 weeks)
Sleep questions from the Liverpool Jet lag Questionnaire
Time frame: From familiarisation to the final experimental session (~4 weeks)
7-day food diary
Time frame: Baseline
Habitual caffeine consumption
Time frame: Baseline
Self-reported 2-week training diary
Time frame: 2 weeks before the main experiment
Chronotype
Time frame: Baseline
Poor sleep quality
Time frame: Baseline
Depressed mood
Time frame: Baseline
Caffeine withdrawal symptoms score
Time frame: From familiarisation to the final experimental session (~4 weeks).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Mar 2026.
- Background: PubMed 33144349Walsh NP, Halson SL, Sargent C, Roach GD, Nedelec M, Gupta L, Leeder J, Fullagar HH, Coutts AJ, Edwards BJ, Pullinger SA, Robertson CM, Burniston JG, Lastella M, Le Meur Y, Hausswirth C, Bender AM, Grandner MA, Samuels CH. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med. 2020 Nov 3:bjsports-2020-102025. doi: 10.1136/bjsports-2020-102025. Online ahead of print.
- Background: PubMed 15865319Drust B, Waterhouse J, Atkinson G, Edwards B, Reilly T. Circadian rhythms in sports performance--an update. Chronobiol Int. 2005;22(1):21-44. doi: 10.1081/cbi-200041039.
- Background: PubMed 37589927Munnilari M, Bommasamudram T, Easow J, Tod D, Varamenti E, Edwards BJ, Ravindrakumar A, Gallagher C, Pullinger SA. Diurnal variation in variables related to cognitive performance: a systematic review. Sleep Breath. 2024 Mar;28(1):495-510. doi: 10.1007/s11325-023-02895-0. Epub 2023 Aug 17.
- Background: PubMed 1365645Mitchell PJ, Redman JR. Effects of caffeine, time of day and user history on study-related performance. Psychopharmacology (Berl). 1992;109(1-2):121-6. doi: 10.1007/BF02245489.
- Individual participant dataSharing planned: No. IPD unavailable due to privacy or ethical restrictions
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Ben J Edwards, PHD principal investigator
Liverpool John Moores University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Caffeine, Placabo and No Pill in people with Caffeine and Placebo - Control, run by Liverpool John Moores University at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 13 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Morning repeated sprint performance test (time frame: From enrolment to last experimental session (~4 weeks)). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07466732, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Mar 2026.