Effect of Fasting Versus Feeding on the Bone Metabolic Response to Running

• Change in C-terminal telopeptide region of collagen type 1 (B-CTX) concentration from baseline [ Time Frame: At 08:00 h (Baseline), 09:00 h, 09:30 h, and 10:15 h (Pre-exercise), after 30 and 60 min of exercise, after 1, 2, and 3 h of recovery and at 1, 2, 3 and 4 day post-exercise ] [ Designated as safety issue: No ]
  B-CTX is a specific marker of bone resorption. It's circulating concentration is altered by both exercise and feeding
  
  

• Change in parathyroid hormone (PTH) concentration from baseline [ Time Frame: At 08:00 h (Baseline), 09:00 h, 09:30 h, and 10:15 h (Pre-exercise), after 30 and 60 min of exercise, after 1, 2, and 3 h of recovery and at 1, 2, 3 and 4 day post-exercise ] [ Designated as safety issue: No ]
  PTH is reported to induce both bone resorption and bone formation. It's circulating concentration is altered by both exercise and feeding.
  
  

Ten physically active males aged 28 ± 4 y (mean ± 1SD) completed two, counterbalanced, 8 d trials. After 3 d on a standardised diet, participants performed 60 min of treadmill running at 65% VO2max on Day 4 following an overnight fast (FAST) or a standardised breakfast (FED). Blood samples were collected at baseline, before exercise, during exercise, for 3h after exercise and on four consecutive follow-up days (FU1-FU4). Plasma/serum were analysed for β CTX, P1NP, OC, bone ALP, PTH, ACa, PO4, OPG, cortisol, leptin and ghrelin.