Paolo Zeppilli, Carlo Picani,
Roberto Corsetti, Antonio Angelucci, Antonio Gianfelici, Carlo Pagliaricci, Roberto
Vannicelli, Vincenzo Palmieri, Cesare Santini, Luca Mainardi*, Sergio Cerutti*.
Cattedra e Centro Studi di Medicina dello Sport, Istituto di Medicina Interna e
Geriatria, Universita Cattolica del Sacro Cuore, Rome, *Dipartimento di Bioingegneria,
Politecnico, Milan, Italy
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Short-term HRV (5-15 minute ECG recordings), carried
out on a stationary tachogram segment (about 90-150 points), seems to be more suitable for
the evaluation of cardiac autonomic modulation in professional and non-professional
sportsmen. Short-term spectral analysis, neglecting very low frequency (VLF) oscillations
and representing low-frequency (LF) and high-frequency (HF) components in normalized
units, allows to distinguish the role respectively of Mayer vasomotor waves (a
quantitative index of sympathetic discharge) and respiratory activity (expression of vagal
modulation). In our experience, athletes seem to be pleased with such a type of
investigation performed in the morning, because it does not modify their training programs
and life behaviour. Moreover, sports physicians can give, in few minutes, information to
athletes about the relative contribute of autonomic components to heart rate spontaneous
fluctuations which can be utilized to assess their training status and performance level.
Obviously, we need an accurate standardization of recording conditions to compare the
power spectrum of a single athlete in different periods of the season and of different
athletes practising the same sports activity. Therefore, from the beginning, our attention
was directed primarily to define the basal pattern of HRV in the healthy well-trained
athlete, that is the pattern which can be observed when all endogenous or exogenous
factors able to modify acutely the neurovegetative balance are removed. For this reason:
we chose to perform short-term HRV exclusively between 8.00 and 9.00 am, after
nocturnal rest and after the subjects were left in supine position for at least 15 minutes
before ECG recording in a quiet room with comfortable temperature (22-24°C);
all athletes were requested to abstain from alcohol, tobacco, drugs or nervine
substances, and from training for at least 20 hours before the ECG recording. The latter
measure was adopted because we documented significant spectral modifications after
exhaustive training sessions or competitions, characterized by appreciable increase of LF
component and LF/HF ratio, indicating sympathetic activation outlasting for many hours.
This phenomenon appeared more accentuated in consequence of closer strenuous training
sessions or competitions leading to chronic fatigue (overreaching or overtraining)12. For example, soccer players may show an increase in LF
component the morning after very exhaustive matches, and professional cyclists, who
demonstrated HRV vagal prevalence after the initial laps of Tour of Italy, revealed a
sudden decrease in HF component (or LF/HF ratio increase) in the final period of Tour with
a decrease in performance;
we monitorized minute by minute the respiratory frequency recommending athletes to
avoid sudden deep breathing that could modify spontaneous heart rate fluctuations.
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