Cardiac baroreflex function and vascular reactivity recovery after aerobic exercise in patients with early cirrhosis.

OBJECTIVE: To investigate the effects of aerobic exercise on the cardiac baroreflex function and vascular reactivity in patients with cirrhosis. METHODS: Thirteen patients with cirrhosis were submitted to exercise and control intervention. At baseline and at 30 and 60 min following intervention, we evaluated cardiac baroreflex sensitivity (cBRS) and the baroreflex effectiveness index (BEI) using sequence technique. Vascular reactivity was assessed inducing reactive hyperemia before and 60 min after intervention. RESULTS: At baseline, there was no difference (P interaction = 0.848) between exercise (from 3.0 ± 0.34 to 14.60 ± 1.06 ml/100ml/min) and control sessions (from 2.38 ± 0.10 to 13.73 ± 1.05 ml/100ml/min) regarding the increase in forearm blood flow during reactive hyperemia. However, this response was higher postexercise (from 3.38 ± 0.31 to 16.58 ± 1.58 ml/100ml/min) than postcontrol intervention (from 2.04 ± 0.23 to 11.98 ± 1.16 ml/100ml/min, P interaction < 0.001). BEI increased at 30- and 60-min postexercise (from 32 ± 7 to 42 ± 7 and 46 ± 7%), but not after control intervention (from 33 ± 6 to 31 ± 5 and 33 ± 7%, P interaction = 0.014). In contrast, cBRS decreased at 30-min postexercise (from 10.3 ± 1.9 to 8.2 ± 1.4 and 10.3 ± 2.1 ms/mmHg) and increased postcontrol intervention (from 7.9 ± 0.9 to 10.5 ± 1.5 and 10.3 ± 1.3 ms/mmHg, P interaction = 0.012). CONCLUSION: The results suggest that a single bout of aerobic exercise improved cardiac baroreflex function and increased vascular reactivity in patients with early-stage cirrhosis.

Constant work-rate test to assess the effects of intradialytic aerobic training in mildly impaired patients with end-stage renal disease: a randomized controlled trial.

OBJECTIVE: To investigate if high-intensity constant work rate (CWR) would constitute a more appropriate testing strategy compared with incremental work rate (IWR) to assess the effectiveness of intradialytic aerobic training in patients with end-stage renal disease (ESRD). DESIGN: Randomized controlled trial. SETTING: Nephrology unit at the university hospital. PARTICIPANTS: Patients (N=28; 47.0±11.9y) under hemodialysis (4.4±4.3y) were randomly assigned to exercise and control groups. INTERVENTION: Patients included in the exercise group underwent a moderate-intensity intradialytic aerobic training program 3 times per week for 12 weeks. MAIN OUTCOME MEASURES: Cardiopulmonary and perceptual responses were obtained during an IWR and a high-intensity CWR test to the limit of tolerance on a cycle ergometer. RESULTS: Training-induced increases in peak oxygen uptake (Vo(2)peak) and time to exercise intolerance (Tlim). Mean improvement in Tlim (97.4%±75.6%) was significantly higher than increases in Vo(2)peak (12%±11.3%) (P<.01); in fact, while Tlim improved 50% to 200% in 9 of 12 patients, Vo(2)peak increases were typically in the 15% to 20% range. CWR test revealed lower metabolic, ventilatory, cardiovascular, and subjective stresses at isotime; in contrast, submaximal responses during the incremental work rate (at the gas exchange threshold) remained unaltered after training. CONCLUSIONS: A laboratory-based measure of endurance exercise capacity (high-intensity CWR test to Tlim) was substantially more sensitive than oxygen uptake at the peak IWR test to unravel the physiologic benefits of an intradialytic aerobic training program in mildly impaired patients with ESRD.