Evaluation of cardiovascular autonomic function tests in normal subjects.

We studied autonomic function in 76 normal adults (aged 20-80 years, 46 men and 30 women) with noninvasive cardiovascular reflex tests. The autonomic function tests included heart rate (HR) response to standing up, during the Valsalva maneuver, deep breathing, diving, and blood pressure (BP) response to standing up, during immersion of the hand in ice water, and a sustained handgrip. The patients were connected to an EKG monitor. All tests were performed in the resting state. The results show that (1) HR response to standing up, during the Valsalva maneuver, and while deep breathing were less variable and more suitable for follow-up; (2) women had a greater fall in systolic BP after standing up, and less rise in diastolic pressure during sustained handgrip than did men; (3) age correlated negatively with the HR response to standing, to deep breathing, Valsalva ratio, and the cold pressure test. But, age correlated positively with a fall in systolic BP as women stood up, but not in men; (4) there is a significant correlation between the HR response to standing up and the HR response to deep breathing. We concluded that sex and age do have an influence on some autonomic test results. The influence of the former is more related to sympathetic function while that of the latter is related to both the sympathetic and parasympathetic system. In addition, a normal range of autonomic function test results in healthy subjects is proposed.