Stress hormones following intense cycling exercise: Insights into overtraining

It has been suggested that resting levels of stress hormones can reflect the cumulative stress associated with rigorous training and therefore may be used as a diagnostic tool to prevent overtraining in athletes. In order to establish whether one intense interval training session could affect resting cortisol concentrations on the following two days, blood was collected from seven collegiate cyclists both immediately after, and for two mornings following one interval cycling session. The validity of using salivary cortisol measures during and following intense training was also investigated. Data indicate that increases in cortisol following one bout of intense interval training do not affect baseline values assessed one and two days following the training session. Additionally, whereas salivary cortisol measures can be used to reflect large changes in serum cortisol post-exercise, it is unlikely that this index of cortisol status can be used to identify subtle changes in this hormone at rest.;Stress hormones and cycling performance were assessed in eight accomplished cyclists before, during and after a three-week intense interval cycling program. Training improved cycling performance which tended to peaked on the eighth day of recovery. Resting stress hormones were unchanged from baseline values throughout the study. Interestingly, weekly performance monitoring was shown to be useful for predicting when during the recovery period a cyclist demonstrated his peak performance.;Stress hormones and cycling performance were measured following both one and ten intense interval cycling sessions in seven collegiate cyclists. Additionally, stress hormones and performance were monitored following ten successive interval training sessions when performed while consuming either a moderate- or high-carbohydrate diet. Results from this study indicate that 4-6 days of recovery are required to achieve peak cycling performance and one day of interval training can cause early morning concentrations of cortisol and testosterone to be suppressed 24 hours after training. Ten successive interval training sessions caused blunted cortisol and testosterone responses to an interval training session but did not affect the catecholamine response. Following ten training sessions serum testosterone was suppressed for two days. No dietary affects on performance or stress hormones were observed.