Haemodynamic Parameters Underlying the Relationship Between Sarcopenia and Blood Pressure Recovery on Standing

Background: Along with sarcopenia, delayed blood pressure (BP) recovery after standing and orthostatic hypotension (OH) are among key clinical challenges associated with ageing. Previous studies have reported an association between sarcopenia and delayed orthostatic BP recovery and OH. However, the haemodynamic mechanisms underlying this association remain unclear. Methods: 107 attendees to a falls and syncope clinic aged 50+ years underwent an active stand test with non-invasive beat-to-beat haemodynamic measurement. Hand grip strength and 5-chair stands time were measured. Muscle mass was estimated using bioelectrical impedance analysis, and participants were classified as non-sarcopenic and sarcopenic. Mixed effects models with linear splines were used to model the effect of sarcopenia status on Modelflow®-derived mean arterial pressure (MAP), cardiac output (CO), total peripheral resistance (TPR), stroke volume (SV) and heart rate (HR) after standing, while controlling for potential confounders. Results: Sarcopenia was associated with: attenuated recovery of MAP in the 10-20s period after standing (β -0.67, P<0.001); attenuated rise to peak (0-10s) and recovery from peak (10-20s) of CO (β -0.05, P<0.001; β 0.06, P<0.001); attenuated recovery (10-20s) of TPR from nadir (β -0.02, P<0.001) and attenuated recovery from peak (10-20s) of SV (β 0.54, P<0.001). HR was not significantly associated with sarcopenia status at any time interval after standing. Conclusion: The attenuated BP recovery after standing seen in sarcopenia appears to be driven by initial diminished peak of CO followed by attenuated recovery of CO from peak and TPR from nadir. The CO finding appears to be driven by SV rather than HR. Potential mechanisms for these findings include: cardio-sarcopenia, the effects of sarcopenia on the autonomic nervous system and/or the skeletal muscle pump.