The effects of intermittent or continuous exercise on renal haemodynamics during moderate-intensity exercise

Purpose Moderate-intensity exercise has beneficial effects for individuals with CKD. However, it is unclear whether intermittent exercise (IE) has a different effect on renal haemodynamics compared to continuous exercise (CE). This study aimed to compare the effects of intermittent or continuous exercise on renal haemodynamics and renal injury during moderate-intensity exercise. Methods Ten males underwent IE or CE to consider the effect of exercise on renal haemodynamics during moderate-intensity exercise. Renal haemodynamic assessment and blood-sampling were conducted before exercise (pre) and immediately (post 0), 30-min (post 30), and 60-min (post 60) after exercise. Urine-sampling was conducted in pre, post 0 and post 60. Results There was no condition-by-time interaction (p = 0.073), condition (p = 0.696), or time (p = 0.433) effects regarding renal blood flow. There was a condition-by-time interaction effect regarding noradrenaline concentrations (p = 0.037). Moreover, both conditions significantly increased noradrenaline concentration at post 0 (IE: p = 0.003, CE: p < 0.001) and remained significantly higher in post 30 (p < 0.001) and post 60 (p < 0.001). Significant difference was found in noradrenaline concentrations at post 0 when comparing IE and CE (399 ± 119 vs. 552 ± 224 pg/ml, p = 0.037). Urinary neutrophil gelatinase-associated lipocalin concentrations increased at post 60 (p = 0.009), but none of them exceeded the cutoff values for the definition of renal damage. Other renal injury biomarkers showed a similar pattern. Conclusion These findings suggest that IE has a similar effect on renal haemodynamics and function, and AKI biomarkers compared to CE.