Healthy Adult Male
Conditions
Brief summary
This study is the first to examine the effects of core temperature elevation on kynurenine pathway (KP) metabolites in healthy young males. It was hypothesized that rise in core temperature due to both pasive heating and exercise will initiate a stress response, affecting the concentration of KP metabolites. Additionally, it was expected that the exercise would produce more pronounced effects due to the increased cardiovascular, mechanical, and metabolic demands associated with it. Thus, the the main purpose of the present study was to investigate and to compare the effects of two distinct heat stress modalities on KP metabolites.
Interventions
OTHEREndogenous heating
Exercise was used as the endogenous heating modality, the participant cycled at 60% of his VO2max until rectal temperature reached 39°C
OTHERExogenous heating
Hot-water immersion was used as the exogenous heating modality, where the participants sat immersed in a water bath at 43.5 ± 0.5°C and remained submerged until rectal temperature reached 39°C.
Sponsors
Lithuanian Sports University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 36 Years
Healthy volunteers
Yes
Inclusion criteria
* healthy adults; * age between 18 - 36 years; * physically active (exercising 2-3 times per week); * non-smoking.
Exclusion criteria
* a body mass index (BMI) \> 30 kg/m2; * neurological, cardiovascular, metabolic, and/or inflammatory diseases, or conditions that could be worsened by exposure to interventions and that could affect experimental variables; * involvement in temperature manipulation program for ≥ 3 months.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in glucose (mmol/L) | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | The glucose concentration (in mmol/L) was measured using an automatic blood glucose meter Glucocard X-mini-Plus (Arkray Inc, Japan). |
| Change in lactate (mmol/L) | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | The lactate concentration (in mmol/L) was measured using an Accutrend Plus System (Roche, Germany). |
| Changes in prolactin concentration (ng/mL) | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | The venous prolactin (in ng/mL) was measured using enzyme-linked immunosorbent assay kit and a Spark multimode microplate reader (Tecan, Austria). |
| Change in plasma metabolites of the kynurenine pathway (μm) | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | 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. |
| Rectal temperature (°C) | Day 1 (during both heating modalities until Tre reached 39°C, followed by a recovery phase until Trec reached 37.5°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. |
| Change in heart rate (bpm) | Day 1 (during both heating modalities until Tre reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | Heart rate (in bpm) was recorded using a heart rate sensor with a chest strap (Polar, Finland). |
| Change in physiological strain index | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | A physiological strain index (PSI) was used to indicate heat strain. PSI = 5 x (Tret - Tre0) x (39.5 - Tre0)\^-1+ 5 x (HRt - HR0) x (180 - HR0)\^-1, where rectal temperature (Tre) t and heart rate (HR) t are simultaneous measurements taken every 0.5°C of the heat exposure and Tre0 and HR0 are the initial measurements. |
| Changes in catecholamines concentration (ng/mL) | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | The venous adrenaline and noradrenaline concentrations (in ng/mL) was measured using enzyme-linked immunosorbent assay kits and a Spark multimode microplate reader (Tecan, Austria). |
| Changes in salivary cortisol concentration (µg/dL) | Day 1 (every 0.5 °C until rectal temperature (Trec) reached 39°C, followed by a recovery phase until Trec reached 37.5°C) | The saliva samples was collected to measure cortisol level (in µg/dL) using an ELISA kits and a Spark multimode microplate reader (Tecan, Austria). |
Countries
Lithuania
Outcome results
None listed