What are the most effective interval training protocols for improving cycling endurance, and how do periodized plans impact the bodys physiological adaptations to high-intensity exercise, particularly in relation to changes in hormone production and utilization. Specifically, Id like to know more about the role of cortisol, testosterone, and growth hormone in mediating the effects of interval training on cardiovascular and muscular systems, and how this knowledge can be applied to create targeted, data-driven training plans that optimize endurance performance while minimizing the risk of overreaching and injury. For example, how do different types of interval workouts, such as sprint intervals, hill repeats, and tempo intervals, affect the production and utilization of these hormones, and what are the implications for recovery and adaptation. Additionally, are there any differences in the physiological responses to interval training between men and women, and how can this information be used to develop more effective, sex-specific training plans that take into account the unique hormonal and physiological profiles of each individual.