Cardiovascular responses during rest-exercise and exercise-exercise transients

Paolo Bruseghini, A Taboni, G Vinetti, S Camelio, M D’Elia, N Fagoni, G. Ferretti

Risultato della ricerca: Contributo in libroContributo a convegno


If indeed vagal withdrawal determines the rapid response to exercise (phase I), the a large reduction, if not complete suppression, of phase I should be found, when an exercise transient starts from a previous lower steady state exercise rather than from rest. On 15 healthy young subjects we measured beat-by-beat cardiac output (Q̇, Modelflow from Portapres data) and heart rate (fH, ECG) during these cycle ergometer exercise transients: 0–50 W (transient from rest, RT) and 50–100W (transient from exercise, ET). A double exponential was used to compute amplitudes and time constants of phase I and II (A1 and A2; T1 and T2). At steady state, fH was 87.510.4, 109.312.0, and 139.617.1bpm, and Q̇ was 7.31.5, 12.61.6, and 16,11,9L/min, at rest, 50W and 100W, respectively. In RT, A1 and A2 for fH were 11.78.6 and 11.34.7bpm; the corresponding T1 and T2 were 1.61.9 and 14.421.3s. For Q̇, we had: A1=4.01.8L/min, A2=1.51.4L/min, T1=3.21.8s, T2=11.312.2s. In ET, the double exponential model provided preposterous A1 and T1 values and extremely high T2 values (>100s). Subsequent use of a mono exponential model provided, for fH, A=29.78.9bpm and T=7.74.9s, and for Q̇, A=3.58.6L/min, and T=7.05.7s. The A and T in ET did not differ from the A2 and T2 of RT. We conclude that a single exponential model is more adequate to describe ET and this single exponential corresponds to the second exponential of RT. Our results are compatible with the vagal withdrawal hypothesis.
Lingua originaleEnglish
Titolo della pubblicazione ospiteBook of abstract
Numero di pagine1
Stato di pubblicazionePubblicato - 2018
Evento69th National Congress of the Italian Physiological Society - Firenze
Durata: 19 set 201821 set 2018


Convegno69th National Congress of the Italian Physiological Society


  • Cardiovascular responses
  • exercise transients


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