Vol. 273, Issue 5, H2128-H2134, November 1997
Age effects on interrelationships between lung volume and
heart rate during standing
Garrett
Stanley1,
Davide
Verotta2,3,
Noah
Craft2,
Ronald A.
Siegel2, and
Janice B.
Schwartz4
1 Department of Mechanical
Engineering, University of California, Berkeley 94720;
2 Department of Pharmaceutical
Chemistry and Pharmacy, University of California, San Francisco,
California 94143; and Departments of
3 Epidemiology and
Biostatistics and 4 Clinical
Pharmacology and Geriatrics, Northwestern University Medical
School, Chicago, Illinois 60611
To determine the effects of aging and posture
on the relationship between respiration and heart rate (HR), we
collected 5 min of lung volume and R-R interval data from 7 young (27 ± 3 yr, mean ± SD) and 10 old (69 ± 6 yr) healthy humans
during spontaneous breathing while they were supine (SU) and standing
(ST). Lung volume and HR power spectra and transfer functions between
lung volume and HR were estimated. Age and position effects and
age-position interactions were determined by analysis of variance for
repeated measures. Older subjects had a lower and more variable
respiration rate (P < 0.03, P < 0.04), but both age groups
exhibited decreased rate of respiration and increased tidal volume with
ST (P < 0.05, P < 0.005). ST decreased lung
volume-to-HR transfer function magnitude in both groups
(P < 0.07). The more
marked age-related differences were in phase angle. Both SU and ST
phase angles were greater in older subjects
(P < 0.003). ST decreased phase
angle in young but increased phase angle in older subjects
(P < 0.001). In conclusion, respiration, and respiration-HR interrelationships are altered by
aging, with increased time delays between lung volume and HR and
altered relationships with ST.
heart rate variability; autonomics; baroreflex; posture; respiration
