Effect of ingesting carbohydrate only or carbohydrate plus casein protein hydrolysate during a multiday cycling race on left ventricular function, plasma volume expansion and cardiac biomarkers

Mountain Bike Racing Stimulates Osteogenic Bone Signaling and Ingesting Carbohydrate-Protein Compared With Carbohydrate-Only Prevents Acute Recovery Bone Resorption Dominance

ABSTRACT

Oosthuyse, T, Bosch, AN, Kariem, N, and Millen, AME. Mountain bike racing stimulates osteogenic bone signaling and ingesting carbohydrate-protein compared with carbohydrate-only prevents acute recovery bone resorption dominance. J Strength Cond Res 35(2): 292-299, 2021-Mountain biking, unlike road cycling, includes vibrational accelerations but whether it stimulates osteogenic signaling remains unknown. Furthermore, exercise nutrition influences bone turnover, and the effect of ingesting protein during multiday racing was investigated. We measured plasma bone turnover markers, C-terminal telopeptide of type1-collagen (β-CTX) and N-terminal propeptides of type1-procollagen (P1NP), and osteocyte mechanosensory signaling factor, sclerostin (SOST), corrected for plasma volume change, before (pre-day 1) and 20-60 minutes after (post-day 3) a multiday mountain bike race in 18 male cyclists randomly assigned to ingest carbohydrate-only (CHO-only) or carbohydrate-with-casein protein hydrolysate (CHO-PRO) during racing. Fourteen cyclists (n = 7 per group) completed the race, and data were analyzed with p < 0.05 accepted as significant. Plasma SOST decreased similarly in both groups (mean ± SD, CHO-only: 877 ± 451 to 628 ± 473 pg·ml-1, p = 0.004; CHO-PRO: 888 ± 411 to 650 ± 443 pg·ml-1, p = 0.003), suggesting that osteocytes sense mountain biking as mechanical loading. However, the bone formation marker, P1NP, remained unchanged in both groups, whereas the bone resorption marker, β-CTX, increased in CHO-only (0.19 ± 0.034 to 0.31 ± 0.074 ng·ml-1, p = 0.0036) but remained unchanged in CHO-PRO (0.25 ± 0.079 to 0.26 ± 0.074 ng·ml-1, p = 0.95). Mountain bike racing does stimulate osteogenic bone signaling but bone formation is not increased acutely after multiday mountain biking; investigation for a delayed effect is warranted. The acute recovery increase in bone resorption with CHO-only is prevented by ingesting CHO-PRO during racing.

Arterial Stiffness and Left Ventricular Diastolic Function in Endurance Athletes

The present study investigated the relationship between arterial stiffness and left ventricular diastolic function in endurance-trained athletes. Sixteen young male endurance-trained athletes and nine sedentary of similar age men participated in this study. Resting measures in carotid-femoral pulse wave velocity were obtained to assess arterial stiffness. Left ventricular diastolic function was assessed using 2-dimensional echocardiography. The athletes tended to have lower arterial stiffness than the controls (P=0.071). Transmitral A-waves in the athletes were significantly lower (P=0.018) than the controls, and left ventricular mass (P=0.034), transmitral E-wave/A-wave (P=0.005) and peak early diastolic mitral annular velocity at the septal site (P=0.005) in the athletes were significantly greater than the controls. A significant correlation was found between arterial stiffness and left ventricular diastolic function (E-wave: r=- 0.682, P=0.003, E-wave/A-wave: r=- 0.712, P=0.002, peak early diastolic mitral annular velocity at the septal site: r=- 0.557, P=0.025) in the athletes, whereas no correlation was found in controls. These results suggest that lower arterial stiffness is associated with higher left ventricular diastolic function in endurance-trained athletes.