If you are unable to keep that pace throughout the entire session then the pace was too intense and needs to be lowered the next time. 65%-70% ofwel max intensity is best for creating the optimal calorie burn without reaching the point where the work has become too intense and https://redbottom.us/categories/regular/health/222-the-comprehensive-guide-to-pediatric-nutrition-optimizing-health-from-infancy-to-adolescence