Background: Wave intensity analysis (WIA) is a time domain-based approach [1] that provides useful insights into arterial haemodynamics. We assessed the relationship between the major waves identified by WIA and age and sex in healthy individuals.

Methods: 65 healthy people (age 21 – 78yr; 43 male) participated. WIA was performed using carotid artery tonometry and Doppler ultrasound. Linear regression or fractional polynomial regression was used to fit data after log transformation if appropriate.

Results: The initial compression wave (S wave) accompanying ejection declined non-linearly with age (adjusted r² for age and sex = 0.43; p < 0.001) and was significantly lower in women (p = 0.01). The decompression wave in protodiastole (D wave) showed a curvilinear relationship with age (adjusted r² for age 0.12; p = 0.001), but did not differ by gender. The peak intensity of the reflected wave from the head was higher in men (p = 0.002) but declined with age more markedly in men than women. Wave reflection from the head fell with age (beta (95% CI) = −0.01 (−0.02, −0.00); p = 0.01 (log transformed)) but did not differ significantly by gender. Carotid wave speed was higher in men (p = 0.03) and increased with age in both sexes although the rise was more marked in women.

Conclusions: Cardiac wave intensity falls with age in healthy individuals and is lower in women. Wave reflections from the head are reduced in healthy older people.