PT  - JOURNAL ARTICLE
AU  - I A O'Brien
AU  - P O'Hare
AU  - R J Corrall
TI  - Heart rate variability in healthy subjects: effect of age and the derivation of normal ranges for tests of autonomic function.
AID  - 10.1136/hrt.55.4.348
DP  - 1986 Apr 01
TA  - British Heart Journal
PG  - 348--354
VI  - 55
IP  - 4
4099  - http://heart.bmj.com/content/55/4/348.short
4100  - http://heart.bmj.com/content/55/4/348.full
SO  - Heart1986 Apr 01; 55
AB  - The diagnosis of autonomic neuropathy frequently depends on results of tests which elicit reflex changes in heart rate. Few well-documented normal ranges are available for these tests. The present study was designed to investigate the effect of age upon heart rate variability at rest and in response to a single deep breath, the Valsalva manoeuvre, and standing. A computerised method of measurement of R-R interval variation was used to study heart rate responses in 310 healthy subjects aged 18-85 years. Heart rate variation during each procedure showed a skewed distribution and a statistically significant negative correlation with age. Normal ranges (90% and 95% confidence limits) for subjects aged 20-75 years were calculated for heart rate difference (max-min) and ratio (max/min) and standard deviation (SD). Heart rate responses were less than the 95th centile in at least one of the four procedures in 39 (12.6%) out of the 310 subjects, and were below this limit in two or more tests in five (1.6%) subjects. In view of the decline in heart rate variation with increasing age, normal ranges for tests of autonomic function must be related to the age of the subject.