Table 1.

Battery of cardiovascular reflex tests

Tests	Technique	Normal response	Borderline value	Abnormal value
Tests to investigate parasympathetic function
Heart rate response to deep breathing	Beat‐to‐beat variation while the patient breathes in and out (b.p.m.)	≥15	11–14	≤10
Heart rate response to standing	30:15 ratio (ratio of R‐R interval measured at beats 30 and 15 after standing)	≥1.04	1.01–1.03	≤1.00
Heart rate response to Valsalva maneuver	Valsalva ratio (ratio of longest to shortest R‐R interval measured while performing the Valsalva maneuver)	≥1.21	1.11–1.20	≤1.10
Tests to investigate sympathetic function
Blood pressure response to standing	Decrease in systolic pressure by supine to standing	≤10 mmHg	11–29 mmHg	≥30 mmHg
Blood pressure response to sustained handgrip	Increase in diastolic pressure by squeezing a handgrip dynamometer	≥16 mmHg	11–15 mmHg	≤10 mmHg