AthletesNATRITRAILNCT02519764
Evaluation of the Impact of a Hydration Protocol "at Thirst" on Natremia of the Ultra Trail du Mont-Blanc, 2015 Runners
A study testing Hydration when thirsty. and Not hydration when thirsty in people with Athletes and Healthy, run by Centre Hospitalier Universitaire de Nīmes at 2 sites in France.
Trial summary
The main objective of this study is to evaluate the impact of a hydration protocol "at thirst" compared to other "not at thirst" hydration protocols on the changes in serum sodium in runners of the Ultra Trail Mont-Blanc (UTMB) in 2015. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- What is being tested?
- Hydration when thirsty. and Not hydration when thirsty
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 198 participants
- Where
- 2 sitesFrance
- Study dates
- Aug 2015to 30 Aug 2015
- 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 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- The subject must have given his/her informed and signed consent
- The subject must be insured or beneficiary of a health insurance plan
- The subject is participating in the 2015 Mont-Blanc Ultra Trail and has no contra-indication for ultra-trail activities
Who cannot join
- The subject is participating in another study
- The subject is in an exclusion period determined by a previous study
- The subject is under judicial protection, under tutorship or curatorship
- The subject refuses to sign the consent
- It is impossible to correctly inform the subject
- The subject is pregnant or breastfeeding
- The subject will be excluded from the study in case of early drop out (before 15 km of trail).
Trial locations and contacts
2 sites in 1 country.
France2 sites
CHU de Nice - Hôpital St-Roch
Nice, 06001
CHRU de Nîmes - Hôpital Universitaire Carémeau
Nîmes, 30029
About this study
The main objective of this study is to evaluate the impact of a hydration protocol "at thirst" compared to other "not at thirst" hydration protocols on the changes in serum sodium in runners of the Ultra Trail Mont-Blanc (UTMB) in 2015.
Read the detailed description
The secondary objectives of this study are:
- To assess the relationship between hydration protocols and the dropout rate. B. To evaluate the correlation between body weight change before and after the race and serum sodium before and after the race.
- To evaluate the change in serum sodium into major types of conventional hydration protocols.
- To evaluate the incidence of adverse events (cramps, gastrointestinal symptoms, etc ...) depending on the hydration protocol and the serum sodium.
- Being tested
- Hydration when thirsty., Not hydration when thirsty
- Keywords
- volunteer runners who are participating in the 2015 Mont Blanc Ultra Trail, hydration protocol, natremia, Volunteers
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Hydration when thirsty.Other
Volunteers in this arm habitually follow a hydration protocol that advises hydration when thirst is felt.
Not hydration when thirstyOther
Volunteers in this arm habitually follow any other kind of hydration protocol, i.e. not a "hydration when thirsty" protocol.
| Study group | Role | What they receive |
|---|---|---|
| Hydration when thirsty | Experimental | Volunteers in this arm habitually follow a hydration protocol that advises hydration when thirst is felt. Receives: Other: Hydration when thirsty. |
| Not hydration when thirsty | Experimental | Volunteers in this arm habitually follow any other kind of hydration protocol, i.e. not a "hydration when thirsty" protocol. Receives: Other: Not hydration when thirsty |
What is being measured
The primary outcome is the main question the study is designed to answer.
Natremia (mmol/L)
Measured: Baseline
Natremia (mmol/L)
Measured: at finish, Days 0 to 2
Secondary outcomes (64)
Weight (kg)
Measured: Baseline
Weight (kg)
Measured: at finish, Days 0 to 2
What year did you first start running regularly?
(pre-race questionnaire)
Measured: Baseline
What year did you first start running ultra-trail races?
(pre-race questionnaire)
Measured: Baseline
How many 100 miles or Ultra-trails races have you completed?
(pre-race questionnaire)
Measured: Baseline
How many 100 miles or Ultra-trails races have you started but not finished?
(pre-race questionnaire)
Measured: Baseline
What was your AVERAGE WEEKLY running training distance during the 3 months before the UTMB?
(pre-race questionnaire)
Measured: Baseline
What was your HIGHEST running training distance IN ONE WEEK during the 3 months before the UTMB?
(pre-race questionnaire)
Measured: Baseline
What was your LONGEST race or training run during the 3 months before the UTMB?
(pre-race questionnaire)
Measured: Baseline
If you regularly take any medications, please list those here :
(pre-race questionnaire)
Measured: Baseline
What were the main factors you used to decide how much to drink during the race?
(You may select more than one factor, but please be sure to select at least one factor.)
Thirst(1) A pre-determined drinking schedule according to distance or time (2) The maximum amount I could tolerate (3) The amount of change in my body weight (4) My urine color (5) Other (please specify)
(pre-race questionnaire)
Measured: Baseline
What will you primarily drink during the race?
(Please select only one drink option.)?
Water only (1) Mostly water and some electrolyte containing drink (2) About an equal amount of water and electrolyte containing drink (3) Mostly electrolyte containing drink and some water (4) Only electrolyte containing drink (5) Other (please specify): (6)
Measured: before start of race, day -1
Indicate if you plan to use sodium supplements: yes/no
(pre-race questionnaire)
Measured: Baseline
What is the estimated number of sodium supplements you plan to use during the race?
(Please only enter a number for the supplements you use. In other words, you do not need to enter a zero if you did not use the supplement.)
Succeed S! Caps (1) Hammer Endurolyte Capsules (2) Hammer Endurolytes Fizz Tablets (3) SaltStick Caps (4) SaltStick Caps Plus (5) Nuun Electrolyte Enhanced Drink Tabs (6) GU Roctane Electrolyte Capsules (7) GU Brew Electrolyte Tablets (8) Lava Salts Capsules (9) Other (please specify) (10) Other (please specify) (10) Other (please specify) (10)
(pre-race questionnaire)
Measured: Baseline
Reflux/heartburn BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Bloating BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Stomach cramps/pain BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Nausea BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Vomiting BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal cramps/pain BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Flatulence BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Side ache/stitch BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Urge to defecate BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Loose stool/diarrhea BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal bleeding/bloody feces BEFORE THE START OF THE RACE ?
What GI symptoms did you experience… BEFORE THE START OF THE RACE ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Reflux/heartburn FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Bloating FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Stomach cramps/pain FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Nausea FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Vomiting FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal cramps/pain FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Flatulence FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Side ache/stitch FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Urge to defecate FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Loose stool/diarrhea FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal bleeding/bloody feces FROM THE START TO COURMAYEUR ?
What GI symptoms did you experience… FROM THE START TO COURMAYEUR ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Reflux/heartburn FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Bloating FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Stomach cramps/pain FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Nausea FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Vomiting FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal cramps/pain FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Flatulence FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Side ache/stitch FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Urge to defecate FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Loose stool/diarrhea FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal bleeding/bloody feces FROM COURMAYEUR TO CHAMONIX ?
What GI symptoms did you experience… FROM COURMAYEUR TO CHAMONIX ? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Did gastrointestinal (GI) symptoms affect your race performance? yes/no
(post-race questionnaire)
Measured: after race, days 0 to 2
Reflux/heartburn IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Bloating IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Stomach cramps/pain IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Nausea IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Vomiting IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal cramps/pain IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Flatulence IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Side ache/stitch IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Urge to defecate IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
Measured: after race, days 0 to 2
Loose stool/diarrhea IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Intestinal bleeding/bloody feces IN THE PAST (PRIOR TO UTMB) WHILE RUNNING?
What GI symptoms did you experience… IN THE PAST (PRIOR TO UTMB) WHILE RUNNING? Please mark the severity of each symptom using the scale of "None", "Mild", "Moderate", "Severe", or "Very Severe"
(post-race questionnaire)
Measured: after race, days 0 to 2
Did you use any medications (including prescription and over-the-counter) immediately before or during the 2015 UTMB? (post-race questionnaire)
If so, please list
Measured: after race, days 0 to 2
Did you have any muscle cramps during the 2015 UTMB?
Yes Almost, but was able to control any full-blown cramping No
(post-race questionnaire)
Measured: after race, days 0 to 2
If yes, In which muscles did you have an issue with cramping during the 2015 UTMB?
Calf muscles Quadriceps Hamstrings Hip flexors (muscles in front of pelvis and top of leg) Other(s) (please specify): ____________________
(post-race questionnaire)
Measured: after race, days 0 to 2
If yes, Indicate which race section(s) you had issues with muscle cramps (post-race questionnaire)
Start to Courmayeur Courmayeur to Chamonix
(post-race questionnaire)
Measured: after race, days 0 to 2
Have you had muscle cramps during prior ultra-trail runs? yes/no
(post-race questionnaire)
Measured: after race, days 0 to 2
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 Aug 2015 (estimated)
- Study startAug 2015
- Primary completion30 Aug 2015
- Study completion30 Aug 2015
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 AthletesStudies of the same condition, open and under way.
- More trials run by Centre Hospitalier Universitaire de NīmesThe 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
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Investigator
- Enrolment
- 198 participants (actual)
Sponsor and investigators
- Lead sponsor
- Centre Hospitalier Universitaire de Nīmes
- Sponsor type
- University, hospital or other
- Collaborators
- DOKEVER
- Responsible party
- Sponsor
- Investigators
- Olivier Marès, MD, Study director, Centre Hospitalier Universitaire de Nīmes
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02519764
- Sponsor's protocol ID
- LOCAL/2015/OM-01
- Other IDs
- 2015-A00675-44
- Acronym
- NATRITRAIL
- Status last verified
- Aug 2015
- First submitted
- 7 Aug 2015
- Last updated
- 19 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
Publications
Mouzat K, Raoul C, Polge A, Kantar J, Camu W, Lumbroso S. Liver X receptors: from cholesterol regulation to neuroprotection-a new barrier against neurodegeneration in amyotrophic lateral sclerosis? Cell Mol Life Sci. 2016 Oct;73(20):3801-8. doi: 10.1007/s00018-016-2330-y. Epub 2016 Aug 10.
PubMed 27510420
Study at a glance
From the registry record, last updated by the sponsor on 19 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Impact of a Hydration Protocol "at Thirst" on Natremia of the Ultra Trail du Mont-Blanc, 2015 Runners
- ClinicalTrials.gov ID
- NCT02519764
- Acronym / sponsor ID
- NATRITRAIL / LOCAL/2015/OM-01
- Keywords
- volunteer runners who are participating in the 2015 Mont Blanc Ultra Trail, hydration protocol, natremia, Volunteers
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 198 participants (actual)
- Lead sponsor
- Centre Hospitalier Universitaire de NīmesUniversity, hospital or other
- Collaborators
- DOKEVER
- Study start
- Aug 2015
- Primary completion
- 30 Aug 2015 (actual)
- Study completion
- 30 Aug 2015 (actual)
- First posted
- 11 Aug 2015 (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 main objective of this study is to evaluate the impact of a hydration protocol "at thirst" compared to other "not at thirst" hydration protocols on the changes in serum sodium in runners of the Ultra Trail Mont-Blanc (UTMB) in 2015.
Detailed description
The secondary objectives of this study are:
- To assess the relationship between hydration protocols and the dropout rate. B. To evaluate the correlation between body weight change before and after the race and serum sodium before and after the race.
- To evaluate the change in serum sodium into major types of conventional hydration protocols.
- To evaluate the incidence of adverse events (cramps, gastrointestinal symptoms, etc ...) depending on the hydration protocol and the serum sodium.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Hydration when thirsty | Experimental | Other: Hydration when thirsty.Volunteers in this arm habitually follow a hydration protocol that advises hydration when thirst is felt. |
| Not hydration when thirsty | Experimental | Other: Not hydration when thirstyVolunteers in this arm habitually follow any other kind of hydration protocol, i.e. not a "hydration when thirsty" protocol. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- The subject must have given his/her informed and signed consent
- The subject must be insured or beneficiary of a health insurance plan
- The subject is participating in the 2015 Mont-Blanc Ultra Trail and has no contra-indication for ultra-trail activities
Key exclusion criteria (7 listed)
- The subject is participating in another study
- The subject is in an exclusion period determined by a previous study
- The subject is under judicial protection, under tutorship or curatorship
- The subject refuses to sign the consent
- It is impossible to correctly inform the subject
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 |
|---|---|---|
| Hydration when thirsty.Volunteers in this arm habitually follow a hydration protocol that advises hydration when thirst is felt. | Other | Hydration when thirsty |
| Not hydration when thirstyVolunteers in this arm habitually follow any other kind of hydration protocol, i.e. not a "hydration when thirsty" protocol. | Other | Not hydration when thirsty |
Primary outcome
Natremia (mmol/L)
Time frame: Baseline
Natremia (mmol/L)
Time frame: at finish, Days 0 to 2
64 secondary outcomes
Weight (kg)
Time frame: Baseline
Weight (kg)
Time frame: at finish, Days 0 to 2
What year did you first start running regularly?
Time frame: Baseline
What year did you first start running ultra-trail races?
Time frame: Baseline
How many 100 miles or Ultra-trails races have you completed?
Time frame: Baseline
How many 100 miles or Ultra-trails races have you started but not finished?
Time frame: Baseline
What was your AVERAGE WEEKLY running training distance during the 3 months before the UTMB?
Time frame: Baseline
What was your HIGHEST running training distance IN ONE WEEK during the 3 months before the UTMB?
Time frame: Baseline
What was your LONGEST race or training run during the 3 months before the UTMB?
Time frame: Baseline
If you regularly take any medications, please list those here :
Time frame: Baseline
What were the main factors you used to decide how much to drink during the race?
Time frame: Baseline
What will you primarily drink during the race?
Time frame: before start of race, day -1
Indicate if you plan to use sodium supplements: yes/no
Time frame: Baseline
What is the estimated number of sodium supplements you plan to use during the race?
Time frame: Baseline
Reflux/heartburn BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Bloating BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Stomach cramps/pain BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Nausea BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Vomiting BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Intestinal cramps/pain BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Flatulence BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Side ache/stitch BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Urge to defecate BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Loose stool/diarrhea BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Intestinal bleeding/bloody feces BEFORE THE START OF THE RACE ?
Time frame: after race, days 0 to 2
Reflux/heartburn FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Bloating FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Stomach cramps/pain FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Nausea FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Vomiting FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Intestinal cramps/pain FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Flatulence FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Side ache/stitch FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Urge to defecate FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Loose stool/diarrhea FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Intestinal bleeding/bloody feces FROM THE START TO COURMAYEUR ?
Time frame: after race, days 0 to 2
Reflux/heartburn FROM COURMAYEUR TO CHAMONIX ?
Time frame: after race, days 0 to 2
Bloating FROM COURMAYEUR TO CHAMONIX ?
Time frame: after race, days 0 to 2
Stomach cramps/pain FROM COURMAYEUR TO CHAMONIX ?
Time frame: after race, days 0 to 2
Nausea FROM COURMAYEUR TO CHAMONIX ?
Time frame: after race, days 0 to 2
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 19 Nov 2025.
- Results publication: PubMed 27510420Mouzat K, Raoul C, Polge A, Kantar J, Camu W, Lumbroso S. Liver X receptors: from cholesterol regulation to neuroprotection-a new barrier against neurodegeneration in amyotrophic lateral sclerosis? Cell Mol Life Sci. 2016 Oct;73(20):3801-8. doi: 10.1007/s00018-016-2330-y. Epub 2016 Aug 10.
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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.
Olivier Marès, MD study director
Centre Hospitalier Universitaire de Nīmes
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Hydration when thirsty. and Not hydration when thirsty in people with Athletes and Healthy, run by Centre Hospitalier Universitaire de Nīmes at 2 sites in France.
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 3 inclusion and 7 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 19 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in France. 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?
Natremia (mmol/L) (time frame: Baseline). 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 NCT02519764, 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 19 Nov 2025.