An observational study in Cold Exposure, sponsored by University School of Physical Education, Krakow, Poland. Completed at 1 site in Poland. Open to male participants aged 25 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-23.
Sponsored by University School of Physical Education, Krakow, Poland · Observational
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.
219 studies on the registry are indexed under Common Cold; 23 are open to participants now.
This study's enrollment of 30 is below the median of 114 across 25 observational studies indexed under Common Cold.
Browse Common Cold studies →University School of Physical Education, Krakow, Poland is the lead sponsor of 21 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Experienced in winter swimming, regularly swimming in cold water (open water) at least once a week in the period November - March
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
group not practicing winter swimming
group practicing winter swimming
Other: winter swimming
Intervention involves bathing/swimming in cold water during the winter months in open waters
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 \[thousands/μl\].
Time frame: 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 \[mln/μl\],
Time frame: 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) \[g/dl\],
Time frame: 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) \[%\],
Time frame: 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) \[pg\],
Time frame: 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) \[fl\],
Time frame: 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) \[AU\],
Time frame: 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) \[%\],
Time frame: 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) \[s\].
Time frame: 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) \[nmol/min/ml\].
Time frame: 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) \[U/ml\],
Time frame: 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 \[mmol/l\].
Time frame: 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 \[ng/dl\],
Time frame: 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 \[µg/dl\],
Time frame: 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 \[µmol/l\],
Time frame: twice: before the start of cold swimming in November and 5 months later (March), after the end of winter swimming
Plan to share: No
Ran from Jan 2021 to primary completion in Dec 2023, 35 months.
Of 12 observational studies under Common Cold, half reached primary completion within 20 months of starting (the median), counting those still running; a quarter within 2 and three quarters within 35. This study's 35 months is above that.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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University School of Physical Education, Krakow, Poland