Effects of High-Intensity Interval Running Versus Cycling on Sclerostin, and Markers of Bone Turnover and Oxidative Stress in Young Men.

This study compared sclerostin's response to impact versus no-impact high-intensity interval exercise in young men and examined the association between exercise-induced changes in sclerostin and markers of bone turnover and oxidative stress. Twenty healthy men (22.3 ± 2.3 years) performed two high-intensity interval exercise trials (crossover design); running on treadmill and cycling on cycle ergometer. Trials consisted of eight 1 min running or cycling intervals at ≥ 90% of maximal heart rate, separated by 1 min passive recovery intervals. Blood samples were collected at rest (pre-exercise), and 5 min, 1 h, 24 h, and 48 h following each trial. Serum levels of sclerostin, cross-linked telopeptide of type I collagen (CTXI), procollagen type I amino-terminal propeptide (PINP), thiobarbituric acid reactive substances (TBARS), and protein carbonyls (PC) were measured. There was no significant time or exercise mode effect for PINP and PC. A significant time effect was found for sclerostin, CTXI, and TBARS with no significant exercise mode effect and no significant time-by-mode interaction. Sclerostin increased from pre- to 5 min post-exercise (47%, p < 0.05) and returned to baseline within 1 h following the exercise. CTXI increased from pre- to 5 min post-exercise (28%, p < 0.05), then gradually returned to baseline by 48 h. TBARS did not increase significantly from pre- to 5 min post-exercise but significantly decreased from 5 min to 48 h post-exercise. There were no significant correlations between exercise-induced changes in sclerostin and any other marker. In young men, sclerostin's response to high-intensity interval exercise is independent of impact and is not related to changes in bone turnover and oxidative stress markers.