Cardiovascular and renal responses to continuous, moderate and high-intensity interval exercise in mid-spectrum CKD.

Abstract

The purpose of the present investigation was to determine the effect a short acute bout of aerobic exercise had on vascular and renal function in individuals with midspectrum CKD. Six men and fourteen women (Age = 62.0 ± 10 years; BMI = 37.3 ± 8.3; Waist = 98.9 ± 12.7; VO2max = 19.4 ± 4.6; and eGFR = 51.5 ± 6.5) participated in two experimental conditions: high-intensity interval exercise (HIIE) and continuous moderate-intensity exercise (CMIE). Each exercise condition lasted for 30 minutes and was completed after an 8- to 12-hour fast. Ultrasound-determined flow-mediated dilation of the brachial artery (FMD) was assessed before, 1 and 24 hrs after exercise. Blood and urine samples were taken before, 1 and 24 hrs post-exercise. Serum and plasma samples were measured for nitrotyrosine (ᶟ¯NT) asymmetric dimethyl arginine (ADMA), paroxonase-1 (PON-1), total antioxidant capacity (TAC), and creatinine. Urine samples were measured for epidermal growth factor (uEGF) and creatinine and the uEGF/uCr ratio was calculated as a marker of renal function. MDRD and CKD-EPI estimates of glomerular filtration rates were calculated. All samples were analyzed using 2-way repeated-measures ANOVA. Comparison-wise significance was established at p < 0.05. FMD was increased similarly with HIIE and CMIE. FMD increased 4.4% ± 1.4 at 1 hour and 2.9% ± 0.9 at 24 hour post-exercise (p < 0.005). ADMA was decreased 5.9% ± 2.3 by 24 hours after exercise (p < 0.0006), while PON-1 increased 4.6% ± 4.9 (p < 0.0097) and TAC 4.3% ± 4.2 (p < 0.012), reaching their zenith 24 hours post-exercise. Serum creatine decreased by 11% ± 3.2 at 1 and 24 hours after exercise (p < 0.0061) while eGFR increased 1 hour post-exercise and returned to baseline by 24 hours. uEGF/uCr ratio remained unaltered in both exercise conditions; however, eGFR equations MDRD increased by 16.6% ± 4.6 and CKD-EPI increased by 18.9% ± 4.5 were greatest after exercise (MDRD = p < 0.0096 and CKDEPI = p < 0.007). Exercise improves measures of vascular and renal function in mid-spectrum CKD. Results were similar after HIIE and CMIE and may last for several hours after exercise. Therefore, a single episode of HIIE or CMIE transiently improves cardiovascular health in individuals with mid-spectrum CKD.