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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
41
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).
Lithuanian Sports University
Kaunas, Lithuania
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.
Time frame: 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).
Time frame: 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.
Time frame: 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).
Time frame: 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)
Time frame: 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).
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Time frame: 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).
Time frame: 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).
Time frame: 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).
Time frame: 2 days