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BackgroundRenal blood flow (RBF) decreases with exercise, but this change is only temporary, and habitual exercise may be an effective method to improve renal function. The kidney shows structural and functional changes with aging, but it is unclear how aging affects the hemodynamic response of the kidneys to exercise. Therefore, we evaluated the differences in the hemodynamic response of the kidneys to high-intensity exercise between younger and older men.MethodsSixteen men (8 young and 8 older) underwent an incremental exercise test using a cycle ergometer with a 1-min warm up followed by exercise at 10–20 W/min until the discontinuation criteria were met. Renal hemodynamics were assessed before exercise, immediately after exercise, and at 60-min after exercise using ultrasound echo.ResultsHigh-intensity exercise significantly reduced RBF in both groups (younger: ∆  – 53 ± 16%, p = 0.0005; older: ∆  – 53 ± 19%, p = 0.0004). In the younger group, RBF returned to the pre-exercise level 60-min after exercise (∆  – 0.4 ± 5.7%, p > 0.9999). In contrast, RBF 60-min after exercise was significantly lower than that before exercise in the older group (∆  – 24 ± 19%, p = 0.0006). The older group had significantly lower RBF than younger adults 60-min after exercise (423 ± 32 vs. 301 ± 98 mL/min, p = 0.0283).ConclusionsOur findings demonstrate that RBF following high-intensity exercise recovered 60-min after exercise in younger group, whereas RBF recovery was delayed in the older group.

BackgroundHigh-intensity exercise reduces renal blood flow (RBF) and may transiently exacerbate renal dysfunction. RBF has previously been measured invasively by administration of an indicator material; however, non-invasive measurement is now possible with technological innovations. This study examined variations in RBF at different exercise intensities using ultrasound echo.MethodsEight healthy men with normal renal function (eGFRcys 114 ± 19 mL/min/1.73 m2) participated in this study. Using a bicycle ergometer, participants underwent an incremental exercise test using a ramp protocol (20 W/min) until exhaustion in Study 1 and the lactate acid breaking point (LaBP) was calculated. Participants underwent a multi-stage test at exercise intensities of 60, 80, 100, 120, and 140% LaBP in Study 2. RBF was measured by ultrasound echo at rest and 5 min after exercise in Study 1 and at rest and immediately after each exercise in Study 2. To determine the mechanisms behind RBF decline, a catheter was placed into the antecubital vein to study vasoconstriction dynamics.ResultsRBF after maximum exercise decreased by 51% in Study 1. In Study 2, RBF showed no significant decrease until 80% LaBP, and showed a significant decrease (31%) at 100% LaBP compared with at rest (p < 0.01). The sympathetic nervous system may be involved in this reduction in RBF.ConclusionsRBF showed no significant decrease until 80% LaBP, and decreased with an increase in blood lactate. Reduction in RBF with exercise above the intensity at LaBP was due to decreased cross-sectional area rather than time-averaged flow velocity.

BackgroundAcute exercise reduces renal blood flow (RBF). However, the effect of exercise intensity on RBF in patients with chronic kidney disease (CKD) stage 2 is not known. We investigated the association between RBF and exercise intensity in patients with CKD stage 2 using pulsed Doppler ultrasonography.MethodsEight men with CKD stage 2 (cystatin C-based estimate of glomerular filtration rate: 60–89 ml/min/1.73 m2) participated in this study. Using a bicycle ergometer, participants undertook a maximal graded exercise test (MGET) (experiment 1) and a multi-stage exercise test (experiment 2) to determine their lactate threshold (LT). Participants undertook a multi-stage exercise test for 4-min each. Workloads of 60%, 80%, 100%, 120%, and 140% of LT were used in experiment 3. RBF was measured by pulsed Doppler ultrasonography at rest, immediately after exercise, and 1 h after exercise in experiment 1, and at rest and immediately after each exercise bout in experiment 3.ResultsRenal blood flow after the MGET was 52% lower than at rest, and did not recover as well as after the exercise test. Cross-sectional area (CSA) was significantly lower after graded exercise. RBF tended to be lower at 100% of LT and was significantly lower at 120% of LT. CSA was significantly lower at 100% of LT.ConclusionsRenal blood flow does not change during exercise until the LT is reached. These findings may assist in making appropriate exercise recommendations to patients with CKD stage 2.

High‐intensity intermittent exercise (HIIE) has become attractive for presenting a variety of exercise conditions. However, the effects of HIIE on renal function and hemodynamics remain unclear. This study aimed to compare the effects of HIIE and moderate‐intensity continuous exercise (MICE) on renal hemodynamics, renal function, and kidney injury biomarkers. Ten adult males participated in this study. We allowed the participants to perform HIIE or MICE to consider the impact of exercise on renal hemodynamics under both conditions. Renal hemodynamic assessment and blood sampling were conducted before the exercise (pre) and immediately (post 0), 30 min (post 30), and 60 min (post 60) after the exercise. Urine sampling was conducted in the pre, post 0, and post 60 phases. There was no condition‐by‐time interaction (p = 0.614), condition (p = 0.422), or time effect (p = 0.114) regarding renal blood flow. Creatinine‐corrected urinary neutrophil gelatinase‐associated lipocalin concentrations increased at post 60 (p = 0.017), but none exceeded the cut‐off values for defining kidney injury. Moreover, there were no significant changes in other kidney injury biomarkers at any point. These findings suggest that high‐intensity exercise can be performed without decreased RBF or increased kidney injury risk when conducted intermittently for short periods. Visual summary of the current study.

Exercise is restricted for individuals with reduced renal function because exercising reduces blood flow to the kidneys. Safe and effective exercise programs for individuals with reduced renal function have not yet been developed. We previously examined the relationship between exercise intensity and renal blood flow (RBF), revealing that moderate‐intensity exercise did not reduce RBF. Determining the effects of exercise duration on RBF may have valuable clinical applications. The current study examined the effects of a single bout of continuous exercise at lactate threshold (LT) intensity on renal hemodynamics. Eight adult males participated in this study. Participants underwent 30 min of aerobic exercise at LT intensity using a cycle ergometer. Evaluation of renal hemodynamics was performed before and after exercise, in the recovery phase using ultrasound echo. Furthermore, blood and urine samplings were conducted before and after exercise, in the recovery phase. Compared with resting, RBF was not significantly changed immediately after continuous exercise (319 ± 102 vs. 308 ± 79 ml/min; p = 0.976) and exhibited no significant changes in the recovery phase. Moreover, urinary kidney injury molecule‐1 (uKIM‐1) level exhibited no significant change immediately after continuous exercise (0.52 ± 0.20 vs. 0.46 ± 0.27 μg/g creatinine; p = 0.447). In addition, the results revealed no significant change in urinary uKIM‐1 in 60‐min after exercise. Other renal injury biomarkers exhibited a similar pattern. These findings indicate that a single bout of moderate‐intensity continuous exercise maintains RBF and does not induce renal injury.

Background: Cardiac rehabilitation (CR) combined with stress management training has been shown to be associated with fewer clinical events than CR alone. However, there have been no reports on the associations of CR with the psychological condition and detailed physical activities evaluated on the same day. Method: One hundred outpatients who participated in a CR program were graded on the hospital anxiety and depression scale (HADS). We divided them into a high HADS group (n = 32) and a normal HADS group (n = 68) and investigated by whole patients, ischemic heart disease (IHD) patients, and heart failure patients. Results: Overall, the patient age was 70.5 ± 9.6 years, the percentage of males was 73.0%, and the body mass index was 23.4 (21.7–26.0) kg/m2. In the high HADS group, overall functional mobility was poor and the distance in a two-minute walking test was short. Especially in IHD patients, the high HADS group showed high fat mass in body composition and low exercise tolerance and ventilator equivalents in cardiopulmonary exercise test. Conclusions: Depression and anxiety involved poor physical performance in CR outpatients and particularly involved low exercise tolerance in IHD patients. To evaluate accurate physical performance, it is necessary to investigate psychological condition.

Background: The coronavirus disease 2019 (COVID-19) pandemic has restricted people’s activities and necessitated the discontinuation of cardiac rehabilitation (CR) programs for outpatients. In our hospital, CR for outpatients had to be discontinued for 3 months. We investigated the influence of this discontinuation of CR on physical activity, body composition, and dietary intake in cardiovascular outpatients. Method: Seventy-eight outpatients who restarted CR were investigated. We measured body composition, balance test, stage of locomotive syndrome, and food frequency questionnaire (FFQ) results at restart and 3 months later. We also investigated the results of examination that were obtained before discontinuation. Results: With regard to baseline characteristics, the percentage of male was 62.7% (n = 49), and average age and body mass index were 74.1 ± 8.5 years and 24.9 ± 7.0 kg/m2, respectively. Stage of locomotive syndrome and the results of FFQ did not change significantly. The one-leg standing time with eyes open test significantly worsened at restart (p < 0.001) and significantly improved 3 months later (p = 0.007). With regard to body composition, all limb muscle masses were decreased at restart and decreased even further 3 months later. Conclusions: Discontinuation of CR influenced standing balance and limb muscle mass. While the restart of CR may improve a patient’s balance, more time is required for additional daily physical activities. The recent pandemic-related interruption of CR should inspire the development of alternatives that could ensure the continuity of CR in a future crisis.

•Diastolic dysfunction can be present even in the setting of reduced left ventricular ejection fraction.•The effect of left ventricular diastolic dysfunction on the exercise test results was investigated.•Left ventricular diastolic dysfunction affects ventilatory efficacy in the exercise test.•Low ventilatory efficacy could contribute to a poor prognosis in heart failure. Left ventricular diastolic dysfunction exists in patients with heart failure with reduced ejection fraction and causes activity restriction and a poor prognosis, but there have been few reports about exercise tolerance in patients with diastolic dysfunction, regardless of left ventricular ejection fraction (LVEF). In this study, 294 cardiovascular disease patients who performed a cardiopulmonary exercise test (CPX) with an adequate examination by echocardiography at Fukuoka University Hospital from 2011 to 2020 were investigated. Patients were divided into groups with grade I and grade II or III diastolic dysfunction according to diagnostic criteria, regardless of LVEF, by echocardiography. After adjusting for age, gender, body mass index, smoking, and LVEF by propensity score matching, we compared the results of CPX between the grade I and grade II/III groups. There were no significant differences in hemodynamic parameters, or in the respiratory exchange ratio, oxygen uptake per body weight, oxygen uptake per heart rate, or parameters of ventilatory volume. Ventilatory equivalents per oxygen uptake and per carbon dioxide output were significantly worse in the grade II/III group from the rest to peak periods during CPX. In conclusion, left ventricular diastolic dysfunction worsens ventilatory efficacy during CPX. This effect potentially contributes to a poor prognosis in left ventricular diastolic dysfunction.

Effect of Mild Exercise Training on Glucose Effectiveness in Healthy Men Yuichiro Nishida , MS 1 , Yasuki Higaki , PHD 2 , Kumpei Tokuyama , PHD 4 , Kanta Fujimi , MD 3 , Akira Kiyonaga , MD, PHD 5 , Munehiro Shindo , MS 5 , Yuzo Sato , MD, PHD 1 and Hiroaki Tanaka , PHD 5 1 Research Center of Health, Physical Fitness, and Sports, Nagoya University, Nagoya 2 Department of Community Health Science, Saga Medical School, Saga 3 Department of Internal Medicine, School of Medicine, Fukuoka University, Fukuoka 4 Laboratory of Biochemistry of Exercise and Nutrition, Institute of Health and Sports Science, University of Tsukuba, Ibaraki 5 Faculty of Health and Sports Science Laboratory of Exercise Physiology, Fukuoka University, Fukuoka, Japan Abstract OBJECTIVE —To detect whether mild exercise training improves glucose effectiveness ( S G ), which is the ability of hyperglycemia to promote glucose disposal at basal insulin, in healthy men. RESEARCH DESIGN AND METHODS —Eight healthy men (18–25 years of age) underwent ergometer training at lactate threshold (LT) intensity for 60 min/day for 5 days/week for 6 weeks. An insulin-modified intravenous glucose tolerance test was performed before as well as at 16 h and 1 week after the last training session. S G and insulin sensitivity ( S I ) were estimated using a minimal-model approach. RESULTS —After the exercise training, V o 2max and V o 2 at LT increased by 5 and 34%, respectively ( P < 0.05). The mild exercise training improves S G measured 16 h after the last training session, from 0.018 ± 0.002 to 0.024 ± 0.001 min −1 ( P < 0.05). The elevated S G after exercise training tends to be maintained regardless of detraining for 1 week (0.023 ± 0.002 min −1 , P = 0.09). S I measured at 16 h after the last training session significantly increased (pre-exercise training, 13.9 ± 2.2; 16 h, 18.3 ± 2.4, ×10 −5 · min −1 · pmol/l −1 , P < 0.05) and still remained elevated 1 week after stopping the training regimen (18.6 ± 2.2, ×10 −5 · min −1 · pmol/l −1 , P < 0.05). CONCLUSIONS —Mild exercise training at LT improves S G in healthy men with no change in the body composition. Improving not only S I but also S G through mild exercise training is thus considered to be an effective method for preventing glucose intolerance. BIE, basal insulin component of glucose effectiveness GEZI, glucose effectiveness at zero insulin HGP, hepatic glucose production Ib, basal insulin IVGTT, intravenous glucose tolerance test KG, glucose disappearance constant LT, lactate threshold SG, glucose effectiveness SI, insulin sensitivity Footnotes Address correspondence and reprint requests to Hiroaki Tanaka, PhD, Laboratory of Exercise Physiology, Faculty of Health and Sports Science, Fukuoka University, 8-19-1 Nanakuma Jonan-ku, Fukuoka 814-0133, Japan. E-mail: htanaka{at}fukuoka-u.ac.jp . Received for publication 17 October 2000 and accepted in revised form 27 February 2001. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.