Cardiac Workload in Kidney Transplant Recipients is Unchanged with Low-Intensity Resistance Training but Decreases with Standard Care: A Randomized Controlled Trial

Background: Hypertension remains a major concern in kidney transplant recipients, in part due to the detrimental effects of standard care immunosuppressive therapy. Although resistance training appears safe and may reduce aortic stiffness in kidney transplant recipients, it lacks consistent brachial anti-hypertensive effects, and its impact on central hemodynamics and pulsatile cardiac load remains uncertain. We tested whether 6 months of low-intensity resistance training reduces cardiac workload by lowering central systolic pressure (cSBP) and aortic stiffness at rest. Methods: We analyzed 85 kidney transplant recipients (resistance training: n = 57; standard care: n = 28) from a randomized trial. The intervention group completed biweekly, 60 min, personalized low-intensity resistance sessions targeting the upper and lower body. Radial applanation tonometry with a generalized transfer function enabled central aortic waveform analysis. Cardiac workload was assessed via wasted pressure effort (Ew) and systolic pressure time integral (SPTI). Carotid-femoral pulse wave velocity (cfPWV) was used as a measure of aortic stiffness. Results: At baseline, groups did not differ in cSBP (p = 0.767), Ew (p = 0.321), and SPTI (p = 0.219). Group-by-time interactions were observed for cSBP (p = 0.049), Ew (p = 0.022), and SPTI (p = 0.019). Low-intensity resistance training showed no significant changes, while standard care exhibited reductions in cSBP (mean difference (Δ)6-bas = − 9 mmHg, 95% CI: − 15 to − 3 mmHg, p = 0.004), Ew (Δ_6-bas = − 992 dyne s. cm⁻², 95% CI: − 1864 to − 121 dyne s. cm⁻², p = 0.026), and SPTI (Δ_6-bas = − 3302 mmHg × ms, 95% CI: − 5780 to -824 mmHg × ms, p = 0.010). cf-PWV was unchanged in both groups (time: p = 0.478). Conclusions: Low-intensity resistance training did not affect central arterial load on the heart, supporting its safety in kidney transplant recipients, while standard care may confer a cardiac workload benefit.