DIFFERING EFFECTS OF AGE ON HEART-RATE-VARIABILITY IN MEN AND WOMEN

Gender and age are both known to affect heart rate variability (HRV). Their interaction is not known. HRV, determined from 24-hour Holter re cordings, was compared between gender-matched older (15 men and 15 wom en, aged 67 +/- 3 years, range 64 to 76) and younger (15 men and 15 wo men, aged 33 +/- 4 years, range 26 to 42) subjects selected for an age difference of approximately 35 years. HRV for older and younger subje cts was compared separately by gender. HRV was also compared by gender within groups. Heart rates were significantly higher, and all time an d frequency domain indexes of HRV were significantly lower among the o lder than among the younger men. Among the women only the shorter term indexes of HRV were significantly lower in the older group. When HRV was compared by gender within age groups, there were no significant di fferences between men and women in the older group. In the younger gro up, men had lower heart rates, and all 24-hour time domain indexes of HRV, except those that reflect vagal modulation of heart rate, were si gnificantly higher than those in women. We conclude that HRV is compar able in older men and women. However, HRV is differently affected by a ge. In men, for whom initial levels of HRV ore significantly higher, o lder age is associated with a global reduction in HRV, reflecting redu ctions in both sympathetic and parasympathetic modulation and a loss o f circadian variability. In women, older age is associated mainly with a decline in shorter term indexes of HRV without significant changes in circadian variability. (C) 1997 by Excerpta Medica, Inc.