Impaired gastrointestinal function outside the esophagus has been found in achalasic patients. Moreover, achalasia may occur in diseases in which a systemic dysautonomia is evident. These findings raise the question of whether a generalized subclinical alteration of autonomic control is also present in primary achalasia. Cardiovascular reflex tests and power spectral analysis of heart rate variability were studied in patients with primary achalasia to establish whether autonomic nervous system changes are present in districts other than the gastrointestinal tract. Nineteen normotensive patients with untreated primary achalasia and with no history of cardiac, renal, or endocrinological diseases were examined. Cardiovascular reflex tests included: the tilt test (10 min at 65 degrees), Valsalva maneuver (40 mm Hg for 15 sec), deep breathing (6 breaths/min), and sustained handgrip (30% of maximal effort for 5 min). The parameters evaluated were systolic and diastolic blood pressure (continuously recorded), ECG, oronasal and thoracic respiration, tachogram, and plethysmogram. To evaluate the balance between parasympathetic and sympathetic functions, power spectral analysis of the heart rate variability was carried out. Each patient was paired with two sex- and age-matched healthy controls. In achalasic patients the head-up tilt test, Valsalva maneuver, deep breathing test, and sustained handgrip did not show significant differences from the control group. Low-frequency (LF) and high-frequency (HF) spectral powers and the ratio of LF to HF did not differ in both groups. This study failed to disclose impaired cardiovascular autonomic control in achalasic patients. We suggest that in primary achalasia the defect is limited to the gastrointestinal tract.