Effects of 3-week repeated cold water immersion on leukocyte counts and cardiovascular factors: an exploratory study

Ninja Versteeg; Ron Clijsen; Erich Hohenauer

doi:10.3389/fphys.2023.1197585

Effects of 3-week repeated cold water immersion on leukocyte counts and cardiovascular factors: an exploratory study

Front Physiol. 2023 Aug 29:14:1197585. doi: 10.3389/fphys.2023.1197585. eCollection 2023.

Authors

Ninja Versteeg¹, Ron Clijsen^{1

2

3

4}, Erich Hohenauer^{1

2

3

4

5}

Affiliations

¹ Rehabilitation and Exercise Science Laboratory (RESlab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland.
² International University of Applied Sciences THIM, Landquart, Switzerland.
³ Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium.
⁴ Department of Health, Bern University of Applied Sciences, Berne, Switzerland.
⁵ Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland.

Abstract

Aim: This exploratory study aimed to investigate the effects of a 3-week repeated cold water immersion (CWI) intervention on leukocyte counts and cardiovascular factors (mean arterial pressure [MAP], heart rate [HR]) in healthy men. Methods: A total of n = 12, non-cold-adapted men (age: 25.2 ± 4.0 years; height: 177.8 ± 5.6 cm; weight: 73.8 ± 6.5 kg) were randomly allocated to the CWI or control (CON) group. The CWI group underwent a 3-week repeated CWI intervention (12min at 7°C, 4x/week). The CON group did not receive any cold exposure or therapy. Total leukocyte numbers and proportions (neutrophils, basophils, eosinophils, monocytes, lymphocytes) and cardiovascular factors (MAP, HR) were assessed at baseline and after the 3-week intervention period. Results: Total leukocyte count decreased in CWI (p = 0.027, 95% CI -2.35 to -0.20 × 10³/µL) and CON (p = 0.043, 95% CI -2.75 to -0.50 × 10³/µL). CWI showed a decrease in neutrophil number (p = 0.028, 95% CI -1.55 to -0.25 × 10³/µL) and proportion (p = 0.046, 95% CI -6.42 to 0.56%). In contrast, CON showed no significant change (p > 0.05). No differences were found for other leukocyte subtypes in CWI or CON (all p > 0.05). MAP (p = 0.028, 95% CI -17 to -8 mmHg) and HR (p = 0.027, 95% CI -7 to -2 bpm) were reduced in CWI, whereas CON showed no change (p > 0.05). Conclusion: The results suggest no relevant effects of 3-week repeated CWI on leukocyte counts in healthy men. Due to methodological limitations, the effects on the investigated cardiovascular factors remain unclear. Further studies with larger sample sizes are needed to examine the effects on immune function and cardiovascular health.

Keywords: blood count; cardiovascular factors; cold water immersion; cryotherapy; immune system; leukocytes.