Plasma norepinephrine and heart rate dynamics during recovery from submaximal exercise in man |
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Authors: | Renza Perini Claudio Orizio Alessandro Comandè Maurizio Castellano Marina Beschi Arsenio Veicsteinas |
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Institution: | (1) Institute of Physiology, Department of Biomedical Sciences and Biotechnologies, University of Brescia, via Valsabbina 19, I-25 124 Brescia, Italy;(2) Institute of Internal Medicine, Department of Medical Sciences, University of Brescia, Italy |
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Abstract: | Summary The time course of heart rate (HR) and venous blood norepinephrine concentration NE], as an expression of the sympathetic
nervous activity (SNA), was studied in six sedentary young men during recovery from three periods of cycle ergometer exercise
at 21%±2.8%, 43%±2.1% and 65%±2.3% of
respectively (mean±SE). The HR decreased mono-exponentially withτ values of 13.6±1.6 s, 32.7±5.6 s and 55.8±8.1s respectively in the three periods of exercise. At the low exercise level no
change in NE] was found. At medium and high exercise intensity: (a) NE] increased significantly at the 5th min of exercise
(ΔNE]=207.7±22.5 pg·ml−1 and 521.3±58.3 pg·ml−1 respectively); (b) after a time lag of 1 min NE] decreased exponentially (τ=87 s and 101 s respectively); (c) in the 1st min HR decreased about 35 beats · min−1; (d) from the 2nd to 5th min of recovery HR and NE] were linearly related (100 pg·ml−1
ΔNE]5 beats ·min−1). In the 1st min of recovery, independent of the exercise intensity, the adjustment of HR appears to have been due mainly
to the prompt restoration of vagal tone. The further decrease in HR toward the resting value could then be attributed to the
return of SNA to the pre-exercise level. |
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Keywords: | Heart rate Norepinephrine Recovery Exertion |
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