TemperatureNCT06685627
Core Temperature in Open Water Wetsuited Swimming.
An observational study of Temperature, run by University Hospital, Akershus at 1 site in Norway.
Trial summary
Swimming in cold water is intrinsically unsafe. One of the threats is a fall in core body temperature (Tcore), which adversely affects all body systems and increases the risk of death. Wetsuits mitigate, but do not negate this threat. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Temperature
- What is being tested?
- Open water wetsuited swimming.
- How many people
- 36 participants
- Where
- 1 siteNorway
- Study dates
- 27 Oct 2015to 18 Oct 2020
- Phase
- Observational
- 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 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Trained and highly trained swimmers were recruited from local swim clubs and via social media
Who may be able to join
- Trained and highly trained swimmers.
Who cannot join
- a history of cardiovascular disease, arrhythmias, or gastrointestinal abnormalities precluding the use of rectal temperature measurement.
Trial locations and contacts
1 site in 1 country.
Norway1 site
Institute of Clinical Medicine, University of Oslo, Oslo, Norway
Olso, Olso
About this study
Official title: Core Temperature in Open Water Wetsuited Swimming: a Cohort Study
Swimming in cold water is intrinsically unsafe. One of the threats is a fall in core body temperature (Tcore), which adversely affects all body systems and increases the risk of death. Wetsuits mitigate, but do not negate this threat. Environmental conditions may confound findings from laboratory studies or computer models, thus necessitating open water studies.
This study was designed to investigate the effects of open water wetsuited swimming on core body temperature at a range of different water temperatures between 8.4oC and 24.5oC.
- Conditions
- Temperature
- Being tested
- Open water wetsuited swimming.
- Keywords
- Core temperature, water, swim, wetsuit, cold
- Medical subject headings
- Common Cold
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Open water wetsuited swimming.Other
All swimmers used their own well-fitting wetsuits (5 mm maximum thickness in accordance with World Triathlon guidelines7) and were free to supplement additional neoprene hats, gloves and booties as desired. A safety paramedic attended all swims. Swim distance was self-determined
What is being measured
The primary outcome is the main question the study is designed to answer.
Core temperature
A self-inserted rectal pill was used to continuously measure core temperature in 76 open water swims by 31 wetsuited swimmers in water temperatures ranging from 8.4°C to 24.5°C. The Tcore curves were analysed by linear mixed model regression.
Measured: The thermistor was inserted 15 minutes prior to immersion and measured the core temperature until 30 minutes after egress from the water.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Nov 2024
- Study start27 Oct 2015
- Primary completion18 Oct 2020
- Study completion18 Oct 2020
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 TemperatureStudies 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Akershus
- Sponsor type
- University, hospital or other
- Collaborators
- Oslo University Hospital, Norwegian Armed Forces Medical Service, SINTEF MiNaLab
- Responsible party
- Principal investigator, William James Morton, University Hospital, Akershus
- Investigators
- Jonny Hisdal, PhD, Study director, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06685627
- Sponsor's protocol ID
- Akershus Universitetssykehus
- Status last verified
- Nov 2024
- First submitted
- 11 Nov 2024
- Last updated
- 12 Nov 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: IPD will be shared upon request from a validated body and subject to a data sharing agreement with the University of Oslo.
Publications
Morton WJ, Melau J, Olsen RA, Lovvik OM, Hisdal J, Sovik S. Thermal physiology of open water wetsuited swimming: A cohort study. Temperature (Austin). 2025 Mar 24;12(3):245-263. doi: 10.1080/23328940.2025.2479893. eCollection 2025.
PubMed 40926792
Study at a glance
From the registry record, last updated by the sponsor on 12 Nov 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Core Temperature in Open Water Wetsuited Swimming: a Cohort Study
- ClinicalTrials.gov ID
- NCT06685627
- Acronym / sponsor ID
- Akershus Universitetssykehus
- Conditions
- Temperature
- Keywords
- Core temperature, water, swim, wetsuit, cold
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- University Hospital, AkershusUniversity, hospital or other
- Collaborators
- Oslo University Hospital, Norwegian Armed Forces Medical Service, SINTEF MiNaLab
- Study start
- 27 Oct 2015 (actual)
- Primary completion
- 18 Oct 2020 (actual)
- Study completion
- 18 Oct 2020 (actual)
- First posted
- 12 Nov 2024 (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.
Swimming in cold water is intrinsically unsafe. One of the threats is a fall in core body temperature (Tcore), which adversely affects all body systems and increases the risk of death. Wetsuits mitigate, but do not negate this threat. Environmental conditions may confound findings from laboratory studies or computer models, thus necessitating open water studies.
This study was designed to investigate the effects of open water wetsuited swimming on core body temperature at a range of different water temperatures between 8.4oC and 24.5oC.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Trained and highly trained swimmers were recruited from local swim clubs and via social media
Key inclusion criteria (1 listed)
- Trained and highly trained swimmers.
Key exclusion criteria (1 listed)
- a history of cardiovascular disease, arrhythmias, or gastrointestinal abnormalities precluding the use of rectal temperature measurement.
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 |
|---|---|---|
| Open water wetsuited swimming.All swimmers used their own well-fitting wetsuits (5 mm maximum thickness in accordance with World Triathlon guidelines7) and were free to supplement additional neoprene hats, gloves and booties as desired. A safety paramedic attended all swims. Swim distance was self-determined | Other | – |
Primary outcome
Core temperature
Time frame: The thermistor was inserted 15 minutes prior to immersion and measured the core temperature until 30 minutes after egress from the water.
A self-inserted rectal pill was used to continuously measure core temperature in 76 open water swims by 31 wetsuited swimmers in water temperatures ranging from 8.4°C to 24.5°C. The Tcore curves were analysed by linear mixed model regression.
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 12 Nov 2024.
- Derived from this study: PubMed 40926792Morton WJ, Melau J, Olsen RA, Lovvik OM, Hisdal J, Sovik S. Thermal physiology of open water wetsuited swimming: A cohort study. Temperature (Austin). 2025 Mar 24;12(3):245-263. doi: 10.1080/23328940.2025.2479893. eCollection 2025.
- Individual participant dataSharing planned: Yes. IPD will be shared upon request from a validated body and subject to a data sharing agreement with the University of Oslo.
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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.
Jonny Hisdal, PhD study director
Institute of Clinical Medicine, University of Oslo, Oslo, Norway
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Temperature, run by University Hospital, Akershus at 1 site in Norway.
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 1 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 12 Nov 2024. 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 Norway. 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?
Core temperature (time frame: The thermistor was inserted 15 minutes prior to immersion and measured the core temperature until 30 minutes after egress from the water.). 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 NCT06685627, 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 12 Nov 2024; AzTrials last refreshed its copy on 1 Nov 2026.