CaffeineNCT01167478
Neurophysiological Reserve With Caffeine Manipulation
A study testing Caffeine in people with Caffeine and Placebo, run by University of Sao Paulo at 1 site in Brazil.
Trial summary
The objective of this study is to verify if there is a neurophysiologic reserve when caffeine and placebo perceived as caffeine are manipulated in closed- and opened-loop exercises. Parameters of excitability level of skeletal muscle and Central Nervous System (CNS), and peripheral metabolism will be measured Read more about this study
- Who is it for?
- Ages 18 to 35 years, men only
- What is being tested?
- Caffeine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteBrazil
- Study dates
- Mar 2011to Sep 2011
- Phase
- Interventional
- Are there results?
- None posted in the registry
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
- Men only
- No healthy volunteers
- Adult
Who may be able to join
- trained cyclists
- trained in long distance races
Who cannot join
- Maximum oxygen uptake lower than 55 ml/kg/min
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Neurophysiological Reserve: Peripheral and Central Effects of Caffeine Manipulation
The objective of this study is to verify if there is a neurophysiologic reserve when caffeine and placebo perceived as caffeine are manipulated in closed- and opened-loop exercises. Parameters of excitability level of skeletal muscle and Central Nervous System (CNS), and peripheral metabolism will be measured
Read the detailed description
A neurophysiological reserve related to central mechanisms is supposed to be present, which should be observed when an increased central drive occurs. In theory, according to the central regulation model of effort, an increased performance could be due to the elevation on Central Nervous System excitability and activity, since exercise is not peripherally limited. Conversely, the absence of muscle performance improvement to the increased central drive promoted by caffeine would be an evidence for a peripherally localized neurophysiological limit and would indicate the absence of reserve. Therefore, if present, this reserve could be verified by using peripheral and central measures derived from electric-stimulation, evoked twitch and interpolated twitch techniques, associated to measures of EMG and peripheral metabolism, when caffeine is manipulated during closed- and opened-loop exercise.
In addition, there should also be possible to access the reserve without stimulant substance manipulation (placebo effect). By teleological argument derived from the central regulation model of effort, a neurophysiological reserve would be a natural mechanism to protect the cellular integrity. Therefore, it would be reasonable to hypothesize that, if present, a reserve would be observed by an increase in performance promoted by an elevation in central drive when placebo is perceived as caffeine. Unfortunately, however, no study utilized this experimental approach, including measures of central and peripheral activity during closed- and opened-loop exercise, to consistently respond the reserve question.
- Being tested
- Caffeine
- Keywords
- Exercise, Caffeine, Reserve
- Medical subject headings
- Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CaffeineDietary supplement
After ingestion of 6 mg.kg-1 of body mass of caffeine, subjects will perform the one exercise trial.
CaffeineDietary supplement
6 mg/kg of body mass of caffeine will be ingested by subjects before exercise.
| Study group | Role | What they receive |
|---|---|---|
| Caffeine | Experimental | Not described Receives: Dietary Supplement: Caffeine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Neurophysiological reserve evidenced by caffeine
The time to cover a 4-km trial (closed-loop) or the time to exhaustion in an incremental intensity test (opened-loop) can show if the caffeine manipulation affects the performance. In addition, measures of CNS excitability such as EMG during the closed-loop exercise or at the exhaustion point in the opened-loop exercise, and measures such as the amplitude of H reflex, the rate of increase in H reflex/M wave relationship, can indicate if some central or peripheral alteration occurred during the exercises.
Measured: Immediately after the administration (around 10 minutes)
Neurophysiological reserve evidenced by caffeine
The time to cover a 4-km trial (closed-loop) or the time to exhaustion in an incremental intensity test (opened-loop) can show if the placebo manipulation affects the performance. In addition, measures of CNS excitability such as EMG during the closed-loop exercise or at the exhaustion point in the opened-loop exercise, and measures such as the amplitude of H reflex, the rate of increase in H reflex/M wave relationship, can indicate if some central or peripheral alteration ocurred during the exercises.
Measured: Immediately after the administration (around 10 minutes)
Secondary outcomes (1)
Neurophysiological reserve evidenced by placebo
The placebo should also promote decrease in time of trial or increase in mean power output during a closed-loop exercise, elevation in time to exhaustion and maximal power output during an opened-loop exercise, and increase in maximal voluntary isometric contraction (MVIC) and time to contraction in a target force. Also, there should be a higher CNS excitability such as: 1) higher EMG during closed-loop exercise and higher EMG at the exhaustion point in an opened-loop exercise; 2) increased amplitude of H reflex; 3) elevation on the rate of increase in H reflex/M wave relationship.
Measured: Immediately after the administration (around 10 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Jul 2010 (estimated)
- Study startMar 2011
- Primary completionJun 2011
- Study completionSep 2011
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for CaffeineStudies of the same condition, open and under way.
- More trials run by University of Sao PauloThe sponsor's other registered studies.
- 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
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Sao Paulo
- Sponsor type
- University, hospital or other
- Collaborators
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Responsible party
- Principal investigator, Flavio de Oliveira Pires, University of Sao Paulo
- Investigators
- Carlos Ugrinowitsch, PhD, Principal investigator, University of Sao Paulo
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01167478
- Sponsor's protocol ID
- EEFE026
- Other IDs
- 2010/01317-0
- Status last verified
- Dec 2014
- First submitted
- 21 Jul 2010
- Last updated
- 5 Dec 2014
- Results posted
- No
- Data monitoring committee
- No
Publications
Lambert EV, St Clair Gibson A, Noakes TD. Complex systems model of fatigue: integrative homoeostatic control of peripheral physiological systems during exercise in humans. Br J Sports Med. 2005 Jan;39(1):52-62. doi: 10.1136/bjsm.2003.011247.
PubMed 15618343
Study at a glance
From the registry record, last updated by the sponsor on 5 Dec 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Neurophysiological Reserve: Peripheral and Central Effects of Caffeine Manipulation
- ClinicalTrials.gov ID
- NCT01167478
- Acronym / sponsor ID
- EEFE026
- Keywords
- Exercise, Caffeine, Reserve
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University of Sao PauloUniversity, hospital or other
- Collaborators
- Fundação de Amparo à Pesquisa do Estado de São Paulo
- Study start
- Mar 2011
- Primary completion
- Jun 2011 (actual)
- Study completion
- Sep 2011 (actual)
- First posted
- 22 Jul 2010 (estimated)
- 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.
The objective of this study is to verify if there is a neurophysiologic reserve when caffeine and placebo perceived as caffeine are manipulated in closed- and opened-loop exercises. Parameters of excitability level of skeletal muscle and Central Nervous System (CNS), and peripheral metabolism will be measured
Detailed description
A neurophysiological reserve related to central mechanisms is supposed to be present, which should be observed when an increased central drive occurs. In theory, according to the central regulation model of effort, an increased performance could be due to the elevation on Central Nervous System excitability and activity, since exercise is not peripherally limited. Conversely, the absence of muscle performance improvement to the increased central drive promoted by caffeine would be an evidence for a peripherally localized neurophysiological limit and would indicate the absence of reserve. Therefore, if present, this reserve could be verified by using peripheral and central measures derived from electric-stimulation, evoked twitch and interpolated twitch techniques, associated to measures of EMG and peripheral metabolism, when caffeine is manipulated during closed- and opened-loop exercise.
In addition, there should also be possible to access the reserve without stimulant substance manipulation (placebo effect). By teleological argument derived from the central regulation model of effort, a neurophysiological reserve would be a natural mechanism to protect the cellular integrity. Therefore, it would be reasonable to hypothesize that, if present, a reserve would be observed by an increase in performance promoted by an elevation in central drive when placebo is perceived as caffeine. Unfortunately, however, no study utilized this experimental approach, including measures of central and peripheral activity during closed- and opened-loop exercise, to consistently respond the reserve question.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Double blind (participant, investigator)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Caffeine | Experimental | Dietary Supplement: Caffeine |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- trained cyclists
- trained in long distance races
Key exclusion criteria (1 listed)
- Maximum oxygen uptake lower than 55 ml/kg/min
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 |
|---|---|---|
| CaffeineAfter ingestion of 6 mg.kg-1 of body mass of caffeine, subjects will perform the one exercise trial. | Dietary supplement | Caffeine |
| Caffeine6 mg/kg of body mass of caffeine will be ingested by subjects before exercise. | Dietary supplement | Caffeine |
Primary outcome
Neurophysiological reserve evidenced by caffeine
Time frame: Immediately after the administration (around 10 minutes)
The time to cover a 4-km trial (closed-loop) or the time to exhaustion in an incremental intensity test (opened-loop) can show if the caffeine manipulation affects the performance. In addition, measures of CNS excitability such as EMG during the closed-loop exercise or at the exhaustion point in the opened-loop exercise, and measures such as the amplitude of H reflex, the rate of increase in H reflex/M wave relationship, can indicate if some central or peripheral alteration occurred during the exercises.
Neurophysiological reserve evidenced by caffeine
Time frame: Immediately after the administration (around 10 minutes)
The time to cover a 4-km trial (closed-loop) or the time to exhaustion in an incremental intensity test (opened-loop) can show if the placebo manipulation affects the performance. In addition, measures of CNS excitability such as EMG during the closed-loop exercise or at the exhaustion point in the opened-loop exercise, and measures such as the amplitude of H reflex, the rate of increase in H reflex/M wave relationship, can indicate if some central or peripheral alteration ocurred during the exercises.
1 secondary outcome
Neurophysiological reserve evidenced by placebo
Time frame: Immediately after the administration (around 10 minutes)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Dec 2014.
- Background: PubMed 15618343Lambert EV, St Clair Gibson A, Noakes TD. Complex systems model of fatigue: integrative homoeostatic control of peripheral physiological systems during exercise in humans. Br J Sports Med. 2005 Jan;39(1):52-62. doi: 10.1136/bjsm.2003.011247.
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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. This study is not recruiting at the moment.
Carlos Ugrinowitsch, PhD principal investigator
University of Sao Paulo
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine in people with Caffeine and Placebo, run by University of Sao Paulo at 1 site in Brazil.
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 2 inclusion and 1 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: finished, as of the sponsor's last update on 5 Dec 2014. 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 Brazil. 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.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Neurophysiological reserve evidenced by caffeine (time frame: Immediately after the administration (around 10 minutes)). The study lists 2 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 NCT01167478, which also lists 1 linked publication.
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 5 Dec 2014.