POWER SPECTRAL-ANALYSIS OF RR INTERVAL AND BLOOD-PRESSURE SHORT-TERM VARIABILITY AT REST AND DURING DYNAMIC EXERCISE - COMPARISON BETWEEN CYCLISTS AND CONTROLS
F. Macor et al., POWER SPECTRAL-ANALYSIS OF RR INTERVAL AND BLOOD-PRESSURE SHORT-TERM VARIABILITY AT REST AND DURING DYNAMIC EXERCISE - COMPARISON BETWEEN CYCLISTS AND CONTROLS, International journal of sports medicine, 17(3), 1996, pp. 175-181
To determine the adaptations of the autonomic nervous system in the co
ntrol of heart rate and blood pressure induced by endurance training,
10 competitive cyclists aged 27+/-7 years and 10 age-, weight- and hei
ght-matched sedentary controls were subjected to Power Spectral Analys
is of the RR interval and of blood pressure at supine rest and during
submaximal cycloergometric exercise test in the supine position at 20
% and 40 % of maximal workload. At rest, the high-frequency (HF) power
of the RR interval was higher in cyclists (p < 0.05) compared to cont
rols, whereas the power spectrum of both systolic and diastolic blood
pressure did not differ between cyclists and controls. During exercise
the variance, the low-frequency (LF) and the HF power of the RR inter
val decreased significantly (p < 0.005) and similarly in cyclists and
controls. The LF/HF ratio of the RR interval increased (p < 0.001) and
the alfa index of baroreflex sensitivity decreased (p < 0.05) without
differences between cyclists and controls. The variance of both systo
lic and diastolic blood pressure increased (p < 0.001 and p < 0.005, r
espectively) as well as the HF power of systolic blood pressure (p < 0
.001) similarly in cyclists and in controls. In conclusion, the data o
f the present study suggest that competitive cycling causes an enhance
d vagal drive to the sinus node, whereas the neural control of blood p
ressure is not affected. During exercise a vagal withdrawal and a symp
athetic activation in the neural control of heart rate, together with
a reduction of baroreflex sensitivity are operative. These changes are
similar in cyclists and controls.