Autonomic responses to the Valsalva manoeuvre in healthy subjects.

To assess normal autonomic haemodynamic responses to the Valsalva manoeuvre, 158 healthy unmedicated subjects, aged 25-60 years, were examined. For measurement of beat-to-beat blood pressure on a finger, the Finapres instrument was used. Phase-to-phase changes in instantaneous blood pressure and heart rate and the latency response between the end of a Valsalva manoeuvre and points on the resultant blood pressure and heart rate were calculated, and the reference limits for various indices were determined. Sex had no or only marginal effect on blood pressure or heart rate responses or latencies. Ageing was accompanied by a smaller decrease and smaller partial recovery of blood pressure during the strain, with attenuation of reflectory bradycardia, and lengthening of the latencies. It is concluded that age-related reference values should be applied in the interpretation of the Valsalva responses. The following responses should be analysed: mean blood pressure decrease and partial recovery during the strain (adrenergic vasoconstrictor function), reflectory bradycardia after the strain (parasympathetic function), and the latencies (sympathetic and parasympathetic function).