Acute biochemical and physiological responses to prolonged road cycling in competitive youth athletes: a...

Road cycling requires high-intensity efforts from athletes due to the prolonged and intense training sessions. The impact of the effort is reflected in physiological changes described by acute biochemical responses. Monitoring these metabolic signals is essential for optimizing training and safeguarding health. This report aims to analyze the behavior of acute biochemical and physiological changes induced by a prolonged road cycling session in competitive youth athletes, to identify safe and effective training strategies.

Eighteen competitive youth cyclists rode for 115-km prolonged road cycling session. Anthropometric data (body weight, height, body fat percentage, muscle mass, limb circumferences) and physiological measures (blood pressure, fasting glucose) were collected. Venous blood samples were analyzed for urea, creatinine, uric acid, total cholesterol, triglycerides, sodium, potassium, calcium, chloride, and lactate using spectrophotometry.

Postexercise, significant increases were observed in urea (P<0.001, d=1.53), creatinine (P<0.001, d=1.13), uric acid (P<0.001, d=1.25), triglycerides (P=0.01, d=0.71), potassium (P=0.003, d=0.88), calcium (P<0.001, d=1.15), glucose (P=0.006, d=0.77), and lactate (P<0.001, d=1.48). In contrast, total cholesterol significantly decreased (P=0.005, d=0.79), while sodium and chloride remained unchanged. Thigh circumference increased significantly (45.23 to 51 cm; P<0.001), indicating transient muscle swelling, whereas calf circumference showed no significant change. Resting lactate levels were within normal ranges for trained individuals (0.5-2.2 mmol/L).

These results highlight the pronounced acute metabolic stress induced by prolonged cycling, including protein catabolism, lipid mobilization, electrolyte shifts, and altered carbohydrate metabolism. Regular biochemical assessment is recommended to optimize training, performance, and athlete safety.