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Completed

NCT Number: NCT06223087

Effects of Winter Swimming on Blood 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.

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Key information

Conditions

Cold Exposure Behavior Common Cold Infections Motor Activity Picornaviridae Infections RNA Virus Infections Respiratory Tract Diseases Respiratory Tract Infections Virus Diseases

Age range

25 year–60 year

Sex eligibility

Male

Study type

Observational

Primary location

University of Physical Education

Krakow, 31571, Poland

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Good health, practitioners of winter swimming
  • control group: never did winter swimming and had a sedentary lifestyle.

Exclusion criteria

  • medical contraindications to winter bathing

Treatment and study plan

winter swimming

Other

Intervention involves bathing/swimming in cold water during the winter months in open waters

Primary outcomes

  1. 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].

  2. 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],

  3. 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],

  4. 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) [%],

  5. 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],

  6. 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],

  7. 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],

  8. 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) [%],

  9. 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].

  10. 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].

  11. 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],

  12. 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].

  13. 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],

  14. 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],

  15. 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],

Sponsors and collaborators

Lead sponsor

University School of Physical Education, Krakow, Poland

Other

Registry information

Official study title

Effects of Winter Swimming on Blood Morphological, Rheological, and Biochemical Indicators and Oxidative Stress in Males

Important dates

Study start
2021
Primary completion
2023
Study completion
2024
First posted
Jan 25, 2024
Registry last updated
Jun 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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