The Effect of Cold Exposure on Physiological Markers

The Effect of Cold Water Immersion on Physiological Markers

The goal of this observational study is to examine how different physiological markers change over a two-day period after long-duration whole-body cold-water immersion in healthy young men and women. Specifically, the study aims to address the following questions:

• How do kynurenine pathway metabolites change after cold exposure?
• How do stress markers change after cold exposure?
• How do cytokine levels change after cold exposure?
• How do white blood cells count and distribution change after cold exposure?

Study Overview

• Status: Completed
• Conditions: Healthy Adult Participants
• Intervention / Treatment: Other: Cold water immerssion

• Study Type: Interventional
• Enrollment (Actual): 41
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Lithuania
  • Kaunas, Lithuania, LT-44221
    • Lithuanian Sports University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy adults;
• Age between 18 and 36 years;
• No excessive sporting activities;
• No participation in any temperature-manipulation program or exposure to extreme temperatures within the past 12 weeks.

Exclusion Criteria

• Smokers;
• Use of medication that could affect natural thermoregulation;
• Body mass index greater than 30 kg/m²;
• History of asthma, neurological conditions, cardiovascular disease, or any condition that could be adversely affected by cold exposure.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cold water immerssion; Participants in this arm underwent a long-duration intermittent whole-body cold water immersion protocol. The intervention lasted for 170 minutes in total, using water maintained at a constant temperature of 14°C.	Other: Cold water immerssion; This intervention consisted of intermittent whole-body immersion in 14 °C water. After 20 min of immersion, the subject exited from the bath and rested for 10 min by sitting in the room environment, and then the same procedure was repeated. The cold stress continued until 170 min in total (120 min maximum total immersion time).
No Intervention: Control; Participants in this arm remained at an ambient temperature of 24 °C without whole-body cold water immersion protocol. The control intervention lasted for 170 minutes in total.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in plasma metabolites of the kynurenine pathway (μm)	An ultra-performance liquid chromatography-tandem mass spectrometry system (UPLC-MS/MS) was used to measure venous plasma levels of tryptophan, kynurenine, kynurenic acid, 3-hydroxy-kynurenine, quinolinic acid, nicotinamide and picolinic acid (in μm). The UPLC-MS/MS system uses a Xevo TQ-XS triple quadrupole mass spectrometer (Waters) with a Z-spray electrospray interface, and the system operates in electrospray positive multiple reaction monitoring mode.	2 days
Body temperature (°C)	Rectal temperature (in °C) was measured using a thermocouple (Rectal Probe, Ellab, Denmark) inserted to a depth of 12 cm past the anal sphincter, skin temperature (in °C) was measured with thermistors (Skin/Surface Probe, DM852, Ellab).	1 day
Cold strain index	A cold strain index (CSI) was used to indicate cold strain. CSI = 6.67 x (Tre t - Tre 0) x (35 - Tre 0)^-1 + 3.33 x (Tsk t - Tsk 0) x (20 - Tsk 0)^-1, where rectal temperature (Tre) 0 and skin temperature (Tsk) 0 are initial measurements and Tre t and Tsk t are simultaneous measurements taken at the end of the cold exposure.	1 day
Free cortisol concentration (µg/dl)	The saliva samples was collected to measure free cortisol level (in µg/dl) using an ELISA kit and a Spark multimode microplate reader (Tecan, Austria).	2 days
Cytokines concentrations (pg/ml)	The venous tumor necrosis factor alpha and interleukin-6 (in pg/ml) were measured using an ELISA kits and a Gemini Analyzer (Stratec Biomedical GmbH, Birkenfeld, Germany)	2 days
Total cortisol concentration (nmol/l)	The venous total cortisol consentration (in nmol/l) was measured using an ELISA kit and an automated enzyme immunoassay analyzer (AIA-2000; Tosoh Corp., Tokyo, Japan).	2 days
Catecholamines concentration (ng/ml)	The venous adrenaline and noradrenaline concentrations (in ng/ ml) were measured using an Elisa kit and a Spark multimode microplate reader (Tecan, Austria).	2 days
Complete blood count (10^9/L)	Complete blood count with 5 different white blood count components (absolute neutrophils, lymphocytes, monocytes, eosinophils, basophils) analysis (in 10^9/L) was performed using an automated hematology analyzer (XE-5000, Sysmex Corp, Kobe, Japan).	2 days
Glucose (mmol/l)	The glucose concentration (in mmol/l) was measured using a Cardiocheck PA analyzer (Polymer Technology Systems Inc, Indianapolis, IN, USA).	2 days

Collaborators and Investigators

• Sponsor: Lithuanian Sports University

Study record dates

Study Major Dates

• Study Start (Actual): May 13, 2013
• Primary Completion (Actual): May 6, 2018
• Study Completion (Actual): May 6, 2018

Study Registration Dates

• First Submitted: March 26, 2026
• First Submitted That Met QC Criteria: March 26, 2026
• First Posted (Actual): April 1, 2026

Study Record Updates

• Last Update Posted (Actual): April 7, 2026
• Last Update Submitted That Met QC Criteria: April 1, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: LithuanianSportsU-29

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No