Effect of Repeatedly Applied Cold Water Immersion on Subclinical Atherosclerosis, Inflammation, Fat Accumulation and Lipid Profile Parameters of Volunteers

This study was designed as a cohort observational studyfollowing the group of volunteers practicing CWI. Totally forty volunteers agreed to participate in the study by signing the informed consent, approved by the local ethics committee of UPJŠ Košice. Volunteers were examined in Cardiology and General Medicine outpatient clinics of Faculty of medicine, UPJŠ Košice (1st Department of Internal Medicine; outpatient clinics of Medicomp Košice Ltd.). They underwent the anamnesis and examination with a focus in the first step on matching the inclusion criteria: SCORE for the assessment of the cardiovascular risk as low (≤1%), patients without the suspected diagnosis of the familialhypercholesterolemia, respectively with TC level above 8 mmol/L, respectively TG concentrations above 2.3 mmol/L, male gender, age between 21 and 60, signed informed consent to participate in the study.

Patients with one or more exclusion criteria were not included: volunteers with lipid-lowering therapy or those that received hypolipidemics in the period shorter than 3 months before the study, values of blood lipids outside the inclusion criteria, glucose intolerance and DM,presence of advanced cardiovascular (plague or coronary artery disease, TIA, stroke, etc.) or chronic inflammatory diseases, infection or diseases possible affecting measured parameters and significant lifestyle changes in the last period of 6 months before the CWI.

After the initial examination, 35 volunteers fulfilled the criteria. Volunteers of the study underwent controlled, repeated CWI (5 months 15/11/18 - 15/03/19)based on a following pre-prepared protocol in the cooperation of our physicians and the sport club: Full body CWI in open standing, except the head (same location, timing), frequency three times a weekin the duration of 7-10 minutes. Swimming was permitted. Volunteers must not use neoprene aids (gloves, shoes), caps were allowed. Volunteers should be in the final phase submerged in water, above which there should only be the head and neck. The upper limbs were below the water surface. Non-neoprene footwear was permitted. Volunteers entered the water continuously without stopping. The time of stay in water was calculated from the first contact of the foot with water. On average, the whole body needed to be immersed in water within 30 seconds. The entire study was performed in the nearby lake, where all participants in the active arm were exposed to the same weather and water conditions, which were monitored. Volunteers who did not follow the protocol in more than 15% of the episodes, respectively, with weight, fat or muscle mass changes over 5%, with significant dietary changes were excluded from the study. Equivalent sham control group (N=30) was included fulfilling the inclusion criteria, without the CWI.