SUDDEN INCREASES IN TRAINING VOLUME PRODUCE CHANGES IN STRESS MARKERS

Rama, L., Alves, F., & Teixeira, A. M. (2010). Hormonal, immune, autonomic and mood states variation at the initial preparation phase of a winter season, in Portuguese male swimmers. A paper presented at the XIth International Symposium for Biomechanics and Medicine in Swimming, Oslo, June 1619, 2010.

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This study analyzed the variation of hormonal, immune, autonomic, and mood states after the first mesocycle of a winter swimming season. The behaviors of well-established fatigue markers were evaluated. Portuguese national-level male swimmers (N = 13) served as Ss. Training volume and intensity were recorded. Blood and saliva samples were collected at the beginning of the winter season, and after seven weeks of training at the same time of the day (between 15 and 17 hours). After the last training session, 48 hours of rest were provided. Serum cortisol, free testosterone, salivary cortisol e testosterone, and salivary IgA were measured. The Portuguese version of the Profile of Mood States (POMS) short form was used for psychologically assessing the impact of training.

Training volume per week increased gradually (~17.5%) until it doubled. Significant higher values of serum and salivary cortisol were noted. Although the free testosterone remained stable the testosterone:cortisol ratio decreased significantly. The heart rate variability analysis in the frequency domain revealed an elevation of low frequency:high frequency due to the large increment of low frequency and the decrease of high frequency. The total score of POMS also showed an alteration towards significantly worsening scores.

Implication. Cortisol appears to be a marker of the impact of chronic training effect, showing higher sensibility when compared to testosterone. Autonomic imbalance associating increased sympathetic activity and reduced vagal tone has been proposed as a marker of excessive fatigue and impaired performance. The higher low frequency:high frequency found in this study confirmed this. The results of the POMS demonstrated that first signs of the training stress are of a psychological nature.

Sudden increases in training volume induce significant alterations of the stress hormone cortisol, autonomic balance, and a deterioration of mood states.

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