Respiratory sinus arrhythmia

Age is associated with respiratory sinus arrhythmia in humans (p < .01).

“Older individuals also had greater vagal withdrawal during stress compared to younger individuals as indexed by respiratory sinus arrhythmia (p < .01).”

Humansduring acute psychosocial stressn = 133

Age-related differences in cardiovascular reactivity during acute psychological stress in men and women

The journals of gerontology. Series B, Psychological sciences and social sciences·1 Nov 1999