This observational study aims to evaluate multilevel physiological, molecular, metabolic, intestinal, immunological, and psychophysiological responses to rowing-specific exercise in elite rowers. The study is designed to investigate how maximal and prolonged rowing ergometer exercise influences integrated adaptive mechanisms related to mitochondrial function, metabolic regulation, intestinal permeability, immune activation, DNA damage response, and psychological status. Thirty members of the Polish Youth National Rowing Team, aged 19-24 years, will participate in the study during two different training periods. During the competitive phase, participants will perform a 2000-m maximal rowing ergometer test, whereas during the preparatory phase they will complete a 6000-m rowing ergometer test. Blood samples and physiological measurements will be collected before exercise, immediately after exercise, and after 1 hour of recovery. The study will assess gene expression, circulating biomarkers, flow cytometry parameters, blood morphology, lactate concentration, continuous glucose monitoring data, wearable metabolic sensor measurements, nutritional status, and psychological responses. The primary objective is to identify integrated biomarkers reflecting exercise load, recovery dynamics, and adaptive capacity in highly trained athletes. The study also aims to improve understanding of the interaction between metabolic, mitochondrial, intestinal, immunological, and psychophysiological responses to intensive exercise in rowing.
This study is designed to investigate integrated physiological, molecular, metabolic, intestinal, immunological, and psychophysiological responses to rowing-specific exercise in elite athletes. The study focuses on identifying biomarkers associated with exercise load, early recovery, and adaptive capacity in competitive rowers exposed to maximal and prolonged ergometer exercise. Modern exercise physiology indicates that the response to intensive physical effort involves coordinated interactions between metabolic, mitochondrial, immune, neuroendocrine, and intestinal regulatory systems. High-intensity rowing exercise induces substantial metabolic stress, activation of mitochondrial signaling pathways, inflammatory and stress-related responses, and transient disturbances in intestinal barrier integrity. In addition, psychological factors, including mood state and pre-competition anxiety, may modulate physiological responses to exercise and recovery processes. However, previous studies have typically evaluated isolated physiological or biochemical markers without integrating molecular, cellular, and psychophysiological responses within a rowing-specific exercise model. The study will include 30 competitive rowers, members of the Polish Youth National Rowing Team, aged 19 to 24 years, of both sexes. Assessments will be performed during two distinct phases of the annual training cycle. During the competitive phase (May-June 2026), participants will complete a 2000-m maximal rowing ergometer test. During the preparatory phase (November 2026), participants will perform a 6000-m rowing ergometer test. Both exercise protocols are routinely used within elite rowing training and performance monitoring. Blood samples and physiological measurements will be collected at three time points during each testing session: before exercise (baseline), immediately after exercise, and after 1 hour of recovery. Venous blood samples will be used for hematological, biochemical, molecular, and flow cytometric analyses. Capillary blood samples will be collected for lactate assessment. The study includes several integrated research modules: The metabolic and adaptive response module will evaluate exercise-induced mitochondrial and metabolic signaling through analysis of gene expression related to mitochondrial biogenesis and energy regulation, including PPARGC1A, TFAM, PRKAA1, and SOD2. Circulating biomarkers associated with metabolic stress and adaptive signaling, including GDF15, apelin, irisin, myonectin, HSP70, and BDNF, will also be assessed. Psychological questionnaires evaluating mood state, perceived recovery, and competitive anxiety will be administered to characterize psychophysiological status. The muscle-liver axis module will assess hormonal and metabolic regulation associated with glucose homeostasis and exercise adaptation. Measurements will include insulin, glucagon, FGF21, fetuin-A, IL-6, and myoglobin concentrations, together with expression of genes related to IL-6 signaling, gluconeogenesis, and glucose transport, including STAT3, SOCS3, PCK1, and SLC2A4 (GLUT4). Continuous glucose monitoring (CGM) and wearable metabolic monitoring systems will be used to evaluate glucose dynamics, lactate responses, hydration status, heart rate, and sodium loss during exercise and recovery. The intestinal permeability and exercise-induced endotoxemia module will investigate exercise-associated disruption of intestinal barrier integrity and activation of innate immune responses. The study will assess circulating markers of endotoxemia and immune activation, including lipopolysaccharide (LPS), lipopolysaccharide-binding protein (LBP), soluble CD14, soluble TLR2, and soluble TLR4. Flow cytometry will be used to characterize monocyte phenotypes and receptor expression (CD45, CD14, CD16, TLR2, TLR4), while RT-qPCR analyses will evaluate expression of TLR2 and TLR4 genes. The DNA damage response module will evaluate transient exercise-induced DNA damage and activation of cellular repair mechanisms. Biomarkers of oxidative DNA damage and DNA repair signaling, including 8-OHdG/8-oxo-dG, nucleosomes, HMGB1, AP sites, APE1/APEX1, and poly(ADP-ribose), will be analyzed together with expression of genes involved in DNA damage response and repair pathways, including CDKN1A, GADD45A, APEX1, and PARP1. Body composition analysis will be performed using the TANITA MC-780MA analyzer. Nutritional intake will be evaluated using dietary assessment questionnaires and food records to support interpretation of metabolic and physiological responses. All laboratory analyses will be performed according to standardized laboratory procedures and quality-control protocols. Blood morphology analyses will be conducted immediately after collection, while serum and plasma samples will be processed, centrifuged, and stored at -80°C until analysis. Molecular and flow cytometry analyses will be performed in specialized laboratory facilities using validated methods and equipment. The study is observational in nature and does not involve therapeutic intervention, pharmacological treatment, or experimental supplementation. All exercise procedures represent standard performance tests routinely used in elite rowing training. The project aims to improve understanding of integrated exercise physiology in high-performance athletes and to support development of personalized monitoring strategies for training optimization, recovery management, and early detection of excessive physiological strain.
Study Type
OBSERVATIONAL
Enrollment
30
A standardized maximal rowing ergometer exercise test performed over a distance of 2000 meters during the competitive phase of the training season to evaluate acute physiological and molecular responses to high-intensity exercise.
A standardized prolonged rowing ergometer exercise test performed over a distance of 6000 meters during the preparatory phase of the training season to evaluate physiological and molecular responses to prolonged submaximal exercise.
Changes from baseline in PPARGC1A (PGC-1α) gene expression
Marker of mitochondrial biogenesis and metabolic adaptation to exercise.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Changes from baseline in TFAM gene expression.
Marker of mitochondrial DNA maintenance and transcription.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Changes from baseline in PRKAA1 (AMPKα1) gene expression.
Marker of cellular energy sensing and metabolic stress response
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Changes from baseline in SOD2 gene expression.
Marker of mitochondrial antioxidant defense.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum growth differentiation factor 15 (GDF15) concentration
Marker of mitochondrial and metabolic stress
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum apelin concentration
Exercise-related myokine associated with metabolic regulation.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum heat shock protein 70 (HSP70) concentration
Marker of cellular stress response
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum brain-derived neurotrophic factor (BDNF) concentration
Marker of neuroplasticity and exercise-related neuroregulation.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum myonectin (CTRP15) concentration
Marker of lipid metabolism and energy homeostasis.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum insulin concentration
Marker of glucose regulation and metabolic adaptation.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum glucagon concentration
Marker of hepatic glucose production and gluconeogenesis.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum fetuin-A concentration
Marker of insulin sensitivity and hepatic metabolic response.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum fibroblast growth factor 21 (FGF21) concentration
Marker of metabolic adaptation and energy homeostasis
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum interleukin-6 (IL-6) concentration
Exercise-induced myokine involved in muscle-liver signaling.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in serum myoglobin concentration
Marker of muscle stress and exercise-induced muscle response.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in STAT3 gene expression.
Marker of IL-6 signaling pathway activation
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in SOCS3 gene expression.
Marker of negative feedback regulation of inflammatory signaling.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Changes from baseline in PCK1 gene expression.
Marker of gluconeogenesis regulation.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in SLC2A4 (GLUT4) gene expression.
Marker of skeletal muscle glucose transport
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in plasma lipopolysaccharide (LPS) concentration
Marker of exercise-induced endotoxemia.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in serum lipopolysaccharide-binding protein (LBP) concentration
Marker of endotoxin transport and immune activation.
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum soluble CD14 (sCD14) concentration
Marker of monocyte activation and endotoxin recognition
Time frame: At rest (before the exercise test), immediately after the end of the test, and after 1 hour of recovery.
Change from baseline in serum soluble toll-like receptor 4 (sTLR4) concentration
Marker of innate immune receptor activation.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in serum soluble toll-like receptor 2 (sTLR2) concentration
Marker of innate immune response to bacterial components.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in TLR4 gene expression.
Marker of endotoxin-induced inflammatory signaling
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in TLR2 gene expression.
Marker of innate immune activation.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in TLR4-positive monocyte expression.
Marker of monocyte receptor sensitivity to endotoxins.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in TLR2-positive monocyte expression
Marker of innate immune receptor activation on monocytes.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in serum 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentration
Marker of oxidative DNA damage.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in serum nucleosome concentration
Marker of chromatin fragmentation and cellular stress.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in serum high mobility group box 1 (HMGB1) concentration
Marker of cellular stress and inflammatory signaling.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in number of apurinic/apyrimidinic (AP) sites
Marker of DNA strand damage and base excision repair activity.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in APE1/APEX1 protein concentration
Marker of DNA repair pathway activation.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Change from baseline in poly(ADP-ribose) (PAR) concentration
Marker of PARP activation and DNA repair response
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in CDKN1A (p21) gene expression.
Marker of cell cycle arrest and DNA damage response.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in GADD45A gene expression.
Marker of genomic stress response.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in APEX1 gene expression.
Marker of DNA base excision repair regulation
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in PARP1 gene expression.
Marker of DNA damage sensing and repair signaling.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in blood lactate concentration.
Marker of exercise intensity and metabolic stress.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in hemoglobin concentration
Assessment of exercise-induced changes in hemoglobin concentration.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in hematocrit value
Assessment of exercise-induced changes in hematocrit value.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in red blood cell count
Assessment of exercise-induced changes in red blood cell count.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in mean corpuscular hemoglobin concentration (MCHC)
Assessment of exercise-induced changes in the average hemoglobin concentration within erythrocytes.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in mean corpuscular volume (MCV)
Assessment of exercise-induced changes in the average volume of circulating erythrocytes.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Changes from baseline in mean corpuscular hemoglobin (MCH)
Assessment of exercise-induced changes in the average hemoglobin content per erythrocyte.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
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Change from baseline in white blood cell count
Assessment of exercise-induced immune and inflammatory responses based on leukocyte, neutrophil, lymphocyte, and monocyte counts.
Time frame: At rest (before the exercise test), immediately after the end of the test, after 1 hour of recovery.
Profile of Mood States (POMS) score.
Assessment using the Profile of Mood States (POMS) questionnaire. Total scores range from 0 to 260, with higher scores indicating greater mood disturbance and psychological distress.
Time frame: Before exercise.
Sport Competition Anxiety Test (SCAT) score.
Assessment using the Sport Competition Anxiety Test (SCAT). Total scores range from 10 to 30, with higher scores indicating greater trait competitive anxiety.
Time frame: Before exercise.
Competitive State Anxiety Inventory-2 (CSAI-2) score.
Assessment using the Competitive State Anxiety Inventory-2 (CSAI-2). Total scores range from 27 to 108, with higher scores indicating greater pre-competition anxiety symptoms and self-confidence levels. The questionnaire assesses cognitive anxiety, somatic anxiety, and self-confidence.
Time frame: Before exercise.
Hooper Index score.
Assessment using the Hooper Index questionnaire, calculated as the sum of ratings for fatigue, stress, delayed-onset muscle soreness, and sleep quality. Total scores range from 4 to 28, with higher scores indicating poorer recovery status and greater overall training strain.
Time frame: Before exercise.
Change from baseline in mean interstitial glucose concentration
Mean interstitial glucose concentration (mg/dL) recorded using a continuous glucose monitoring system during the exercise session and throughout the 1-hour post-exercise recovery period. CGM-derived glucose values will be averaged across each assessment period and compared with pre-exercise baseline values.
Time frame: From pre-exercise baseline assessment through exercise and 1-hour post-exercise recovery.
Change from baseline in mean heart rate
Mean heart rate (beats per minute, bpm) continuously recorded using the ONAS10 wearable sensor during exercise and throughout the 1-hour post-exercise recovery period.
Time frame: From pre-exercise baseline through exercise and 1-hour post-exercise recovery.
Change from baseline in estimated lactate concentration
Estimated lactate concentration (mmol/L) continuously derived from sweat biomarker analysis using the ONAS10 wearable microfluidic biosensor during exercise and throughout the 1-hour post-exercise recovery period.
Time frame: From pre-exercise baseline through exercise and 1-hour post-exercise recovery.
Change from baseline in dehydration rate
Dehydration rate (%) estimated from sweat biomarker analysis using the ONAS10 wearable microfluidic biosensor during exercise and the 1-hour post-exercise recovery period.
Time frame: From pre-exercise baseline through exercise and 1-hour post-exercise recovery.
Change from baseline in sweat sodium concentration
Sweat sodium concentration (mg/L or mmol/L) continuously measured using the ONAS10 wearable microfluidic biosensor during exercise and throughout the 1-hour post-exercise recovery period.
Time frame: From pre-exercise baseline through exercise and 1-hour post-exercise recovery.
Change from baseline in estimated sodium loss
Estimated sodium loss (mg) derived from sweat analysis using the ONAS10 wearable microfluidic biosensor during exercise and the 1-hour post-exercise recovery period.
Time frame: From pre-exercise baseline through exercise and 1-hour post-exercise recovery.
Change from baseline in sweat rate
Sweat rate (mL/h) continuously estimated using the ONAS10 wearable microfluidic biosensor during exercise and throughout the 1-hour post-exercise recovery period.
Time frame: From pre-exercise baseline through exercise and 1-hour post-exercise recovery.