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English⧼Colon⧽ F1: Valsalva maneuver from a normal subject (A) and a patient with diabetic autonomic neuropathy (B). The heart rate and beat-to-beat blood pressure responses to the Valsalva maneuver are shown. Expiratory pressure is shown at the bottom. The phases of the Valsalva maneuver (I, II_E, II_L, III, IV) are indicated in the Fig. 1A. Autonomic neuropathy with adrenergic failure is manifested as a loss of phases II_L and IV and delayed blood pressure recovery. Impairment of the vagal component of the baroreflex is manifested as blunting of heart rate response to changes in blood pressure.