Cold ExposureNCT06223087
Effects of Winter Swimming on Blood Indicators and Oxidative Stress in Males
An observational study of Cold Exposure, run by University School of Physical Education, Krakow, Poland at 1 site in Poland.
Trial summary
Exposure of the human body to cold water triggers numerous beneficial physiological changes. The study aimed to assess the impact of regular winter swimming on blood morphological, rheological, and biochemical indicators and activity of antioxidant enzymes in males. Read more about this study
- Who is it for?
- Ages 25 to 60 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Cold Exposure
- What is being tested?
- winter swimming
- How many people
- 30 participants
- Where
- 1 sitePoland
- Study dates
- 1 Jan 2021to 31 Dec 2024
- 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 25 to 60 years
- Men only
- Healthy volunteers accepted
- Adult
Study population: Experienced in winter swimming, regularly swimming in cold water (open water) at least once a week in the period November - March
Who may be able to join
- Good health, practitioners of winter swimming
- control group: never did winter swimming and had a sedentary lifestyle.
Who cannot join
- medical contraindications to winter bathing
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Effects of Winter Swimming on Blood Morphological, Rheological, and Biochemical Indicators and Oxidative Stress in Males
Exposure of the human body to cold water triggers numerous beneficial physiological changes. The study aimed to assess the impact of regular winter swimming on blood morphological, rheological, and biochemical indicators and activity of antioxidant enzymes in males. The study includes winter swimmers and a control group. Blood samples were taken twice - before the start (November) of the winter swimming season and after its end (March). The average duration of ice water baths was 3-5 minutes, with a minimum frequency of once a week. The water temperature during the swimming did not exceed 10°C, approaching 0°C during the winter period.
- Conditions
- Cold Exposure
- Being tested
- winter swimming
- Keywords
- blood, rheology, cold, blood morphology, biochemistry, exercise
- Medical subject headings
- Common Cold, Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
winter swimmingOther
Intervention involves bathing/swimming in cold water during the winter months in open waters
| Study group | Role | What they receive |
|---|---|---|
| control | group not practicing winter swimming | |
| winter swimmers | group practicing winter swimming Receives: Other: winter swimming |
What is being measured
The primary outcome is the main question the study is designed to answer.
blood sampling: platelets and leukocytes
Measurements of:
Platelets [thousands/μl], Leukocytes [thousands/μl], Neutrophils [thousands/μl], Eosinophils [thousands/μl], Basophils [thousands/μl], Lymphocytes [thousands/μl], Monocytes [thousands/μl].
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: erythrocytes
Measurement of:
Erythrocytes [mln/μl],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: haemoglobin
Determination of:
Haemoglobin [g/dl], mean corpuscular haemoglobin concentration (MCHC) [g/dl],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: haematocrit
Determination of:
haematocrit [%], red blood cell distribution width coefficient of variation (RDW-CV) [%],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: haemoglobin mass
Determination of:
mean corpuscular haemoglobin (MCH) [pg],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: Erythrocytes
Determination of mean corpuscular volume (MCV) [fl], red blood cell distribution width standard deviation (RDW-SD) [fl],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: rheology part 1
Determination of red cell elongation index (EI) [arbitrary unit: AU], erythrocyte aggregation amplitude (AMP) [AU],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: rheology part 2
Determination of:
aggregation index (AI) [%],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling:rheology part 3
Determination of:
half-time of total aggregation (t1/2) [s].
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: oxidative stress
Measurement of catalase (CAT) [nmol/min/ml], and glutathione peroxidase (GPx) [nmol/min/ml].
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: oxidative stress - superoxide dismutase
Measurement of superoxide dismutase (SOD) [U/ml],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood biochemistry: Urea
Measurement of:
Urea [mmol/l].
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: Testosterone
Determination of Testosterone concentration [ng/dl],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood sampling: Cortisol
Determination of Cortisol concentration [µg/dl],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
blood biochemistry: Creatine
Determination of Creatinine concentration [µmol/l],
Measured: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Jan 2024
- Study start1 Jan 2021
- Primary completion31 Dec 2023
- Study completion31 Dec 2024
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 Cold ExposureStudies 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
- 30 participants (actual)
Sponsor and investigators
- Lead sponsor
- University School of Physical Education, Krakow, Poland
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Aneta Teleglow, University School of Physical Education, Krakow, Poland
- Investigators
- Aneta Teleglow, Principal investigator, University of Physical Education, Kraków, Poland
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06223087
- Sponsor's protocol ID
- 296/BS/INP/2021
- Status last verified
- Jun 2026
- First submitted
- 30 Dec 2023
- Last updated
- 23 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Teleglow A, Konieczny K, Dobija I, Kusmierczyk J, Tota L, Rembiasz K, Maciejczyk M. Effect of regular winter swimming on blood morphological, rheological, and biochemical indicators and activity of antioxidant enzymes in males. BMC Sports Sci Med Rehabil. 2024 Jun 21;16(1):138. doi: 10.1186/s13102-024-00932-3.
PubMed 38907310
Study at a glance
From the registry record, last updated by the sponsor on 23 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Winter Swimming on Blood Morphological, Rheological, and Biochemical Indicators and Oxidative Stress in Males
- ClinicalTrials.gov ID
- NCT06223087
- Acronym / sponsor ID
- 296/BS/INP/2021
- Conditions
- Cold Exposure
- Keywords
- blood, rheology, cold, blood morphology, biochemistry, exercise
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 30 participants (actual)
- Lead sponsor
- University School of Physical Education, Krakow, PolandUniversity, hospital or other
- Study start
- 1 Jan 2021 (actual)
- Primary completion
- 31 Dec 2023 (actual)
- Study completion
- 31 Dec 2024 (actual)
- First posted
- 25 Jan 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.
Exposure of the human body to cold water triggers numerous beneficial physiological changes. The study aimed to assess the impact of regular winter swimming on blood morphological, rheological, and biochemical indicators and activity of antioxidant enzymes in males. The study includes winter swimmers and a control group. Blood samples were taken twice - before the start (November) of the winter swimming season and after its end (March). The average duration of ice water baths was 3-5 minutes, with a minimum frequency of once a week. The water temperature during the swimming did not exceed 10°C, approaching 0°C during the winter period.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| control | – | –group not practicing winter swimming |
| winter swimmers | – | Other: winter swimminggroup practicing winter swimming |
Who may qualify
- Ages
- 25 to 60 years
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Experienced in winter swimming, regularly swimming in cold water (open water) at least once a week in the period November - March
Key inclusion criteria (2 listed)
- Good health, practitioners of winter swimming
- control group: never did winter swimming and had a sedentary lifestyle.
Key exclusion criteria (1 listed)
- medical contraindications to winter bathing
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 |
|---|---|---|
| winter swimmingIntervention involves bathing/swimming in cold water during the winter months in open waters | Other | winter swimmers |
Primary outcome
blood sampling: platelets and leukocytes
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Measurements of: Platelets [thousands/μl], Leukocytes [thousands/μl], Neutrophils [thousands/μl], Eosinophils [thousands/μl], Basophils [thousands/μl], Lymphocytes [thousands/μl], Monocytes [thousands/μl].
blood sampling: erythrocytes
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Measurement of: Erythrocytes [mln/μl],
blood sampling: haemoglobin
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of: Haemoglobin [g/dl], mean corpuscular haemoglobin concentration (MCHC) [g/dl],
blood sampling: haematocrit
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of: haematocrit [%], red blood cell distribution width coefficient of variation (RDW-CV) [%],
blood sampling: haemoglobin mass
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of: mean corpuscular haemoglobin (MCH) [pg],
blood sampling: Erythrocytes
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of mean corpuscular volume (MCV) [fl], red blood cell distribution width standard deviation (RDW-SD) [fl],
blood sampling: rheology part 1
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of red cell elongation index (EI) [arbitrary unit: AU], erythrocyte aggregation amplitude (AMP) [AU],
blood sampling: rheology part 2
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of: aggregation index (AI) [%],
blood sampling:rheology part 3
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of: half-time of total aggregation (t1/2) [s].
blood sampling: oxidative stress
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Measurement of catalase (CAT) [nmol/min/ml], and glutathione peroxidase (GPx) [nmol/min/ml].
blood sampling: oxidative stress - superoxide dismutase
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Measurement of superoxide dismutase (SOD) [U/ml],
blood biochemistry: Urea
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Measurement of: Urea [mmol/l].
blood sampling: Testosterone
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of Testosterone concentration [ng/dl],
blood sampling: Cortisol
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of Cortisol concentration [µg/dl],
blood biochemistry: Creatine
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Determination of Creatinine concentration [µmol/l],
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 23 Jun 2026.
- Derived from this study: PubMed 38907310Teleglow A, Konieczny K, Dobija I, Kusmierczyk J, Tota L, Rembiasz K, Maciejczyk M. Effect of regular winter swimming on blood morphological, rheological, and biochemical indicators and activity of antioxidant enzymes in males. BMC Sports Sci Med Rehabil. 2024 Jun 21;16(1):138. doi: 10.1186/s13102-024-00932-3.
- Individual participant dataSharing planned: No
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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.
Aneta Teleglow principal investigator
University of Physical Education, Kraków, Poland
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 Cold Exposure, run by University School of Physical Education, Krakow, Poland at 1 site in Poland.
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 23 Jun 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 Poland. 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?
blood sampling: platelets and leukocytes (time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming). The study lists 15 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 NCT06223087, 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 23 Jun 2026.