Effects of Exercise Testing and Cardiac Rehabilitation in Patients with Coronary Heart Disease on Fear and Self-Efficacy of Exercise: A Pilot Study.

BACKGROUND: Exercise fear and low exercise self-efficacy are common in patients attending cardiac rehabilitation (CR). This study tested whether exercise prescription methods influence exercise fear and exercise self-efficacy. We hypothesized that the use of graded exercise testing (GXT) with a target heart rate range exercise prescription, relative to standard exercise prescription using rating of perceived exertion (RPE), would produce greater reductions in exercise fear and increase self-efficacy during CR. METHOD: Patients in CR (N = 32) were randomized to an exercise prescription using either RPE or a target heart rate range. Exercise fear and self-efficacy were assessed with questionnaires at three time points: baseline; after the GXT in target heart rate range group; and at session 6 for the RPE group and CR completion. Items were scored on a five-point Likert-type scale with higher mean scores reflecting higher fear of exercise and higher self-efficacy. To analyze mean differences, a mixed effects analysis was run. RESULTS: There were no significant changes in exercise self-efficacy between baseline and discharge from CR; these were not statistically significant (mean differences baseline - 0.63; end - 0.27 (p = 0.13)). Similarly, there was no change in fear between groups (baseline 0.30; end 0.51 (p = 0.37)). CONCLUSION: Patients in the RPE and target heart rate groups had non-significant changes in exercise self-efficacy over the course of CR. Contrary to our hypothesis, the use of GXT and target heart rate range did not reduce fear, and we noted sustained or increases in fear of exercise among patients with elevated baseline fear. A more targeted psychological intervention seems warranted to reduce exercise fear and self-efficacy in CR.

Acute cardiovascular responses to unilateral bicep curls with blood flow restriction.

A consensus on the acute cardiovascular responses to low intensity (LI) resistance exercise (RE) combined with blood flow restriction (BFR) has not yet been reached. This study was designed to compare acute cardiovascular responses to a single bout of LIRE, high intensity (HI) RE, and LIRE with BFR in physically active young males. Participants completed 3 RE sessions in random order, where each session consists of 4 sets of unilateral dumbbell bicep curls. Cardiovascular hemodynamics were measured at baseline and right after each set of RE. Aortic augmentation index (AIx) was significantly higher after set 2,3,4 of RE in LI + BFR session compared to LI session (P < 0.05). Brachial systolic blood pressure (SBP), heart rate (HR), brachial rate pressure product (RPP), and central RPP responses did not differ between LI and LI + BFR sessions (P > 0.05). HI session had a higher central SBP, brachial RPP, central RPP, and aortic AIx compared to LI session after each set of RE (P < 0.05), but not brachial SBP (P > 0.05). Taken together, this study showed that LIRE combined with BFR acutely augmented aortic stiffness, as also observed in HI session, but myocardial oxygen consumption was only higher in HI session when compared to LI session. Thus, although BFR did not exaggerate cardiovascular responses nor cause extra myocardial oxygen consumption, it should be prescribed with caution when control of acute aortic stiffening is necessary during RE.

Effects of caloric restriction and aerobic exercise on circulating cell-free mitochondrial DNA in patients with moderate to severe chronic kidney disease.

Circulating cell-free mitochondrial DNA (ccf-mtDNA) may induce systemic inflammation, a common condition in chronic kidney disease (CKD), by acting as a damage-associated molecular pattern. We hypothesized that in patients with moderate to severe CKD, aerobic exercise would reduce ccf-mtDNA levels. We performed a post hoc analysis of a multicenter randomized trial (NCT01150851) measuring plasma concentrations of ccf-mtDNA at baseline and 2 and 4 mo after aerobic exercise and caloric restriction. A total of 99 participants had baseline ccf-mtDNA, and 92 participants completed the study. The median age of the participants was 57 yr, 44% were female and 55% were male, 23% had diabetes, and 92% had hypertension. After adjusting for demographics, blood pressure, body mass index, diabetes, and estimated glomerular filtration rate, median ccf-mtDNA concentrations at baseline, 2 mo, and 4 mo were 3.62, 3.08, and 2.78 pM for the usual activity group and 2.01, 2.20, and 2.67 pM for the aerobic exercise group, respectively. A 16.1% greater increase per month in ccf-mtDNA was seen in aerobic exercise versus usual activity (P = 0.024), which was more pronounced with the combination of aerobic exercise and caloric restriction (29.5% greater increase per month). After 4 mo of intervention, ccf-mtDNA increased in the aerobic exercise group by 81.6% (95% confidence interval: 8.2-204.8, P = 0.024) compared with the usual activity group and was more marked in the aerobic exercise and caloric restriction group (181.7% increase, 95% confidence interval: 41.1-462.2, P = 0.003). There was no statistically significant correlation between markers of oxidative stress and inflammation with ccf-mtDNA. Our data indicate that aerobic exercise increased ccf-mtDNA levels in patients with moderate to severe CKD.NEW & NOTEWORTHY The effects of prolonged exercise on circulating cell-free mitochondrial DNA (ccf-mtDNA) have not been explored in patients with chronic kidney disease (CKD). We showed that 4-mo aerobic exercise is associated with an increase in plasma ccf-mtDNA levels in patients with stages 3 or 4 CKD. These changes were not associated with markers of systemic inflammation. Future studies should determine the mechanisms by which healthy lifestyle interventions influence biomarkers of inflammation and oxidative stress in patients with CKD.

Effects of diet and exercise on adipocytokine levels in patients with moderate to severe chronic kidney disease.

BACKGROUND AND AIMS: Obesity is a pro-inflammatory risk factor for progression of CKD and cardiovascular disease. We hypothesized that implementation of caloric restriction and endurance exercise would improve adipocytokine profiles in patients with moderate to severe CKD. METHODS AND RESULTS: We enrolled patients with moderate to severe CKD through a multi-center pilot randomized trial of diet and exercise in a 4-arm design (dietary restriction of 10%-15% reduction in caloric intake, exercise three times/week, combined diet and exercise, and control) (NCT01150851). Adipocytokines (adiponectin and leptin) were measured at the beginning and end of the study period as secondary outcomes. Treatment effect was analyzed in a multivariable model adjusted for baseline outcome values, age, gender, site and diabetes. A total of 122 participants were consented, 111 were randomized (42% female, 25% diabetic, and 91% hypertensive), 104 started intervention and 92 completed the study (Figure 1). Plasma adiponectin levels increased significantly in response to diet by 23% (95% CI: 0.2%, 49.8%, p = 0.048) among participants randomized to the caloric restriction and usual activity arm but not to exercise, whereas circulating leptin did not change by either treatment. CONCLUSION: Our data suggest that dietary caloric restriction increases plasma adiponectin levels in stage 3-4 CKD patients, with limited effect on leptin levels. These findings suggest the potential for improving the metabolic milieu of CKD with moderate calorie restriction.

The effects of 16-weeks of prebiotic supplementation and aerobic exercise training on inflammatory markers, oxidative stress, uremic toxins, and the microbiota in pre-dialysis kidney patients: a randomized controlled trial-protocol paper.

BACKGROUND: Chronic kidney disease (CKD) is characterized by dysbiosis, elevated levels of uremic toxins, systemic inflammation, and increased markers of oxidative stress. These factors lead to an increased risk of cardiovascular disease (CVD) which is common among CKD patients. Supplementation with high amylose maize resistant starch type 2 (RS-2) can change the composition of the gut microbiota, and reduce markers of inflammation and oxidative stress in patients with end-stage renal disease. However, the impact of RS-2 supplementation has not been extensively studied in CKD patients not on dialysis. Aerobic exercise training lowers certain markers of inflammation in CKD patients. Whether combining aerobic training along with RS-2 supplementation has an additive effect on the aforementioned biomarkers in predialysis CKD patients has not been previously investigated. METHODS: The study is being conducted as a 16-week, double-blind, placebo controlled, parallel arm, randomized controlled trial. Sixty stage 3-4 CKD patients (ages of 30-75 years) are being randomized to one of four groups: RS-2 & usual care, RS-2 & aerobic exercise, placebo (cornstarch) & usual care and placebo & exercise. Patients attend four testing sessions: Two baseline (BL) sessions with follow up visits 8 (wk8) and 16 weeks (wk16) later. Fasting blood samples, resting brachial and central blood pressures, and arterial stiffness are collected at BL, wk8 and wk16. A stool sample is collected for analysis of microbial composition and peak oxygen uptake is assessed at BL and wk16. Blood samples will be assayed for p-cresyl sulphate and indoxyl sulphate, c-reactive protein, tumor necrosis factor α, interleukin 6, interleukin 10, monocyte chemoattractant protein 1, malondialdehyde, 8-isoprostanes F2a, endothelin-1 and nitrate/nitrite. Following BL, subjects are randomized to their group. Individuals randomized to conditions involving exercise will attend three supervised moderate intensity (55-65% peak oxygen uptake) aerobic training sessions (treadmills, bikes or elliptical machine) per week for 16 weeks. DISCUSSION: This study has the potential to yield information about the effect of RS-2 supplementation on key biomarkers believed to impact upon the development of CVD in patients with CKD. We are examining whether there is an additive effect of exercise training and RS-2 supplementation on these key variables. TRIAL REGISTRATION: Clinicaltrials.gov Trial registration# NCT03689569 . 9/28/2018, retrospectively registered.

Metabolic Effects of Diet and Exercise in Patients with Moderate to Severe CKD: A Randomized Clinical Trial.

CKD is steadily increasing along with obesity worldwide. Furthermore, obesity is a proinflammatory risk factor for progression of CKD and cardiovascular disease. We tested the hypothesis that implementation of caloric restriction and aerobic exercise is feasible and can improve the proinflammatory metabolic milieu in patients with moderate to severe CKD through a pilot, randomized, 2×2 factorial design trial. Of 122 participants consented, 111 were randomized to receive caloric restriction and aerobic exercise, caloric restriction alone, aerobic exercise alone, or usual care. Of those randomized, 42% were women, 25% were diabetic, and 91% were hypertensive; 104 started intervention, and 92 completed the 4-month study. Primary outcomes were a change from baseline in absolute fat mass, body weight, plasma F2-isoprostane concentrations, and peak oxygen uptake (VO2 peak). Compared with usual care, the combined intervention led to statistically significant decreases in body weight and body fat percentage. Caloric restriction alone also led to significant decreases in these measures, but aerobic exercise alone did not. The combined intervention and each independent intervention also led to significant decreases in F2-isoprostane and IL-6 concentrations. No intervention produced significant changes in VO2 peak, kidney function, or urine albumin-to-creatinine ratio. In conclusion, 4-month dietary calorie restriction and aerobic exercise had significant, albeit clinically modest, benefits on body weight, fat mass, and markers of oxidative stress and inflammatory response in patients with moderate to severe CKD. These results suggest healthy lifestyle interventions as a nonpharmacologic strategy to improve markers of metabolic health in these patients.

Subjective and objective assessment of sedentary behavior among college employees.

BACKGROUND: High levels of sedentary behavior are linked to increased mortality. In the United States, individuals spend 55-70% of their waking day being sedentary. Since most individuals spend large portions of their daily lives at work, quantifying the time engaged in sedentary behavior at work is emerging as an important health determinant. Studies profiling academic institutions, where a variety of personnel with diverse job descriptions are employed, are limited. Available studies focus mostly on subjective methods, with few using objective approaches. Therefore, the purpose of the current study was to assess sedentary behavior among all occupational groups of a college in the Northeastern United States utilizing both a subjective and an objective method. METHODS: College employees (n = 367) completed the Occupational Sitting and Physical Activity Questionnaire (OSPAQ). A sub-sample of these employees (n = 127) subsequently wore an activPAL3 accelerometer 24 h per day for seven consecutive days. Outcome variables were time spent sitting, standing, stepping, and total number of steps. To assess fragmentation of sedentary behavior, the average duration of a sitting bout and sitting bouts/sitting hour were calculated. Differences between administrators, faculty, and staff, were analyzed using multivariate and univariate analyses of variance. RESULTS: The OSPAQ results indicated that administrators spent more of their working day sedentary (73.2 ± 17.7%) than faculty members (58.5 ± 19.6%, p < 0.05). For the objective phase of the study, complete data were analyzed from 86 participants. During a waking day, administrators (64.0 ± 8.1%) were more sedentary than faculty (56.0 ± 7.9%, p < 0.05) and fragmented their sitting less than staff (3.7 ± 0.7 and 4.5 ± 7.9 bouts of sitting/sitting hour, respectively; p < 0.05). This pattern was also seen during working hours, with administrators (4.9 ± 2.1) taking fewer breaks per hour than staff (6.9 ± 3.0, p < 0.05). CONCLUSIONS: Administrators are the most sedentary members of the campus community. However, overall, the level of sedentary behavior among employees was high. This study highlights the need for sedentary behavior interventions in the college/university environment.

The Effects of Chronic Aerobic Exercise on Cardiovascular Risk Factors in Persons with Diabetes Mellitus.

PURPOSE OF REVIEW: Aerobic exercise training is a component of diabetes mellitus (DM) care guidelines due to its favorable effects on glycemic control and cardiovascular disease (CVD) risk factors. The purpose of this review is to outline the recent evidence regarding the clinical effects of chronic aerobic exercise on CVD risk factors in persons with DM and to compare the effects of varying intensities and types of exercise. RECENT FINDINGS: Among individuals with DM, all types of aerobic exercise training can impact positively on some traditional and non-traditional risk factors for CVD. Training programs with a higher volume or intensity induce greater improvements in vascular function, cardiorespiratory fitness (CRF), and lipid profiles. The beneficial outcomes of aerobic training include improvements in glycemic control, endothelial function, oxidative stress, dyslipidemia, myocardial function, adiposity, and CRF. Findings regarding markers of inflammation are discrepant and further research should focus on the role of exercise to impact upon the chronic inflammation associated with DM.

Blood pressure response to acute and chronic exercise in chronic kidney disease.

AIM: The current study was designed to determine if a relationship exists between acute and chronic blood pressure responses to aerobic exercise in pre-dialysis patients. METHODS: Pre-dialysis kidney patients attended four sessions before being randomized to the treatment (n = 25) or control group (n = 21). In session 1, resting blood pressure was recorded, and these measurements were repeated during the second visit when peak oxygen uptake (VO2peak ) was assessed. In the third and fourth sessions, blood pressures were taken prior to a 40 min walk or period of seated rest. After the 40 min walk or seated rest, blood pressures were monitored for 60 min in the laboratory and for the subsequent 24 h. After session 4, subjects in the treatment group trained aerobically at a moderate intensity, three times per week for 16 weeks. Control subjects were asked to be sedentary. All measurements were repeated after 16 weeks of training or sedentary living. RESULTS: Training increased VO2peak (mL/kg per minute) in the treatment group (baseline 19.6 ± 6.7 vs 21.2 ± 7.7, P < 0.05), with no change in the control (18.0 ± 6.0 vs 17.5 ± 5.7) group. Post-exercise hypotension occurred at baseline prior to training but was unaffected by 16 weeks of training. CONCLUSION: Post-exercise hypotension occurs in pre-dialysis patients following aerobic exercise, but short-term moderate-intensity continuous aerobic training has no effect upon this response. There seems to be no relationship between the acute and chronic blood pressure responses to exercise in pre-dialysis kidney patients.

Short-term aerobic exercise and vascular function in CKD stage 3: a randomized controlled trial.

BACKGROUND: The present study was designed to determine the effect of short-term moderate-intensity exercise training on arterial stiffness in patients with chronic kidney disease (CKD) stage 3. STUDY DESIGN: Randomized controlled trial with a parallel-group design. SETTING & PARTICIPANTS: Testing and training sessions were performed at Springfield College. 46 (treatment group, n=25; control group, n=21) patients with CKD with diabetes and/or hypertension completed the study. INTERVENTION: The aerobic training program consisted of 16 weeks of supervised exercise training at 50%-60% peak oxygen uptake (Vo2peak) 3 times per week, while the control group remained sedentary. Identical testing procedures were performed following the 16-week intervention. OUTCOMES: The primary outcome was arterial stiffness. Secondary outcomes were aerobic capacity, various blood parameters (endothelin 1, nitrate/nitrite, and high-sensitivity C-reactive protein), and health-related quality of life. MEASUREMENTS: Arterial stiffness was assessed with aortic pulse wave velocity (PWV), aerobic capacity by Vo2peak, blood parameters by enzyme-linked immunosorbent assays, and health-related quality of life by the 36-Item Short Form Health Survey (SF-36). Participants attended 4 sessions before being randomly assigned to either the treatment or control group. Participants gave consent during the first session, whereas a graded exercise test with measurement of Vo2peak was completed during the second session. During sessions 3 and 4, aortic PWV was measured at rest prior to 40 minutes of either moderate-intensity exercise training or seated rest. A venous blood sample was obtained prior to exercise or rest and participants completed the SF-36 questionnaire. RESULTS: 16 weeks of training led to an 8.2% increase in Vo2peak for the treatment group (P=0.05), but no changes in aortic PWV . LIMITATIONS: Randomization was not concealed and was violated on one occasion; also, use of an indirect measurement of endothelial function and the short duration of the intervention. CONCLUSIONS: Short-term moderate-intensity exercise training does not alter arterial stiffness in patients with CKD, but seems to reduce endothelin 1 levels.

Effects of unilateral and bilateral lower-body heavy resistance exercise on muscle activity and testosterone responses.

Unilateral and bilateral lower-body heavy resistance exercises (HREs) are used for strength training. Little research has examined whether muscle activation and testosterone (TES) responses differ between these exercises. Our purpose was to compare the effects of unilateral and bilateral lower-body HRE on muscle activity using surface electromyography (sEMG) and TES concentrations. Ten resistance-trained, college-aged male athletes (football, track and field) completed 5 testing sessions in which bilateral (back squat [BS]) and unilateral (pitcher squat [PS]) exercises were performed using a counterbalanced design. Sessions 1 and 2 determined estimated maximum strength (10 repetition maximum [10RM]) in the BS and PS. During testing session 3, muscle activation (sEMG) was measured in the right vastus lateralis, biceps femoris, gluteus maximus, and erector spinae (ES) during both BS and PS (stance leg) exercises. In sessions 4 and 5, total TES concentrations (nanomoles per liter) were measured via blood draws at baseline (preexercise), 0, 5, 10, 15, and 30 minutes postexercise after 4 sets of 10 repetitions at the 10RM. Separate repeated-measures analyses of variance examined differences in sEMG and TES between BS and PS (p < 0.05). The sEMG amplitudes were similar (p = 0.80) for BS (0.22 ± 0.06 mV) and PS (0.20 ± 0.07 mV). The TES responses were also similar (p = 0.15) between BS (21.8 ± 6.9 nmol·L(-1)) and PS (26.2 ± 10.1 nmol·L(-1)). The similar lower limb and back sEMG and TES responses may indicate that the neuromuscular and hormonal demands were comparable for both the BS and PS exercises despite the absolute work being less in the PS. The PS exercise may be an effective method for including unilateral exercise into lower-body resistance training when designing training programs for ground-based activities.

Comparison of Ratings of Perceived Exertion and Target Heart Rate-Based Exercise Prescription in Cardiac Rehabilitation: A RANDOMIZED CONTROLLED PILOT STUDY.

PURPOSE: Although ratings of perceived exertion (RPE) are widely used to guide exercise intensity in cardiac rehabilitation (CR), it is unclear whether target heart rate ranges (THRRs) can be implemented in CR programs that predominantly use RPE and what impact this has on changes in exercise capacity. METHODS: We conducted a three-group pilot randomized control trial (#NCT03925493) comparing RPE of 3-4 on the 10-point modified Borg scale, 60-80% of heart rate reserve (HRR) with heart rate (HR) monitored by telemetry, or 60-80% of HRR with a personal HR monitor (HRM) for high-fidelity adherence to THRR. Primary outcomes were protocol fidelity and feasibility. Secondary outcomes included exercise HR, RPE, and changes in functional exercise capacity. RESULTS: Of 48 participants randomized, four patients dropped out, 20 stopped prematurely (COVID-19 pandemic), and 24 completed the protocol. Adherence to THRR was high regardless of HRM, and patients attended a median (IQR) of 33 (23, 36) sessions with no difference between groups. After randomization, HR increased by 1 ± 6, 6 ± 5, and 10 ± 9 bpm ( P = .02); RPE (average score 3.0 ± 0.05) was unchanged, and functional exercise capacity increased by 1.0 ± 1.0, 1.9 ± 1.5, 2.0 ± 1.3 workload METs (effect size between groups, ηp2 = 0.11, P = .20) for the RPE, THRR, and THRR + HRM groups, respectively. CONCLUSIONS: We successfully implemented THRR in an all-RPE CR program without needing an HRM. Patients randomized to THRR had higher exercise HR but similar RPE ratings. The THRR may be preferable to RPE in CR populations for cardiorespiratory fitness gains, but this needs confirmation in an adequately powered trial.

Exercise Prescription Methods and Attitudes in Cardiac Rehabilitation: A NATIONAL SURVEY.

PURPOSE: High-quality exercise training improves outcomes in cardiac rehabilitation (CR), but little is known about how most programs prescribe exercise. Thus, the aim was to describe how current CR programs prescribe exercise. METHODS: We conducted a 33-item anonymous survey of CR program directors registered with the American Association of Cardiovascular and Pulmonary Rehabilitation. We assessed the time, mode, and intensity of exercise prescribed, as well as attitudes about maximal exercise testing and exercise prescription. Results were summarized using descriptive statistics. Open-ended responses were coded and quantitated thematically. RESULTS: Of 1470 program directors, 246 (16.7%) completed the survey. In a typical session of CR, a median of 5, 35, 10, and 5 min was spent on warm-up, aerobic exercise, resistance training, and cooldown, respectively. The primary aerobic modality was the treadmill (55%) or seated dual-action step machine (40%). Maximal exercise testing and high-intensity interval training (HIIT) were infrequently reported (17 and 8% of patients, respectively). The most common method to prescribe exercise intensity was ratings of perceived exertion followed by resting heart rate +20-30 bpm, although 55 unique formulas for establishing a target heart rate or range (THRR) were reported. Moreover, variation in exercise prescription between staff members in the same program was reported in 40% of programs. Program directors reported both strongly favorable and unfavorable opinions toward maximal exercise testing, HIIT, and use of THRR. CONCLUSIONS: Cardiac rehabilitation program directors reported generally consistent exercise time and modes, but widely divergent methods and opinions toward prescribing exercise intensity. Our results suggest a need to better study and standardize exercise intensity in CR.

Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol.

This study was carried out in 2 parts: part 1 was designed to measure the 1 repetition maximum (1RM) bench press with 2 different moderate-velocity tempos (2/0/2) vs. (2/0/4) in male lifters while part 2 compared the hormonal responses at the same tempos as described in part 1. In both parts 1 and 2, the 1RMs (lbs) were higher on the 2/0/2 tempo than on the 2/0/4 tempo. The change in plasma volume (PV) was greater after the 2/0/4 tempo (-5.7 ± 1.7% vs. 0.96 ± 1.2%, p < 0.05). All blood parameters were significantly (p < 0.05) higher post-exercise compared with baseline. With PV corrected, insulin-like growth factor 1 (IGF-1) (ng·mL⁻¹) was higher with the 2/0/2 tempo only (pre-exercise: 277.4 ± 21.8, post-exercise: 308.1 ± 22.9; 2/0/4 tempo pre-exercise: 277.2 ± 17.6, post-exercise: 284.8 ± 21.2). In conclusion, heavier loads can be lifted and more total work can be performed using a (2/0/2) tempo compared with a slower (2/0/4) tempo, but with the exception of IGF-1, the hormonal responses are similar. Individuals may get the same metabolic responses to training by using different tempos, but they will need to use less weight at a slower tempo.

Substrate Utilization is Influenced by Acute Dietary Carbohydrate Intake in Active, Healthy Females.

The present study compared the metabolic responses between a single low-carbohydrate (LC) and low-fat (LF) meal followed by an aerobic exercise bout in females. Subjects included 8 active, premenopausal females. Subjects completed a LC and LF testing session. Respiratory gas exchange (RER) measurements were taken for 20 min fasted, for 55 min postprandial (PP), and during 30 min of exercise. Blood was collected for assessment of glucose (G), insulin (IN), triglycerides (TG), and free fatty acids (FFA) during the final 10 min of each time period. The LF meal provided 396 kcal (78% carbohydrate, 7% fat, and 15% protein). The LC meal provided 392 kcal (15% carbohydrate, 68% fat, and 18% protein). No significant differences existed between test meals for fasting blood measurements. PP IN (µU·mL(-1)) levels were significantly lower following LC compared to LF [10.7 (6.1) vs. 26.0 (21.0)]. Postexercise (PE) FFA (mEq·L(-1)) levels were significantly greater following LC [1.1 (0.3) vs. 0.5 (0.3)]. PE TG (mg·dL(-1)) levels were significantly greater following LC [152.0 (53.1) vs. 114.4 (40.9)]. RER was significantly lower at all time points following LC compared to LF. In moderately active adult females, ingestion of a single LC meal resulted in greater lipid oxidation at rest and during exercise as compared to a single LF meal. Although macronutrient distribution appears to have dictated substrate utilization in the present study, more research is needed regarding the long-term effects of macronutrient redistribution with and without exercise on substrate utilization. Key pointsThe relative carbohydrate content of a single meal has a significant impact on postprandial metabolism and substrate utilization in healthy, active females.A single bout of aerobic exercise performed within an hour of meal ingestion has the potential to modify the postprandial response.Interventions aimed at improving body composition and preventing chronic disease should focus on dietary macronutrient redistribution and postprandial metabolism in concert with exercise training.

Isometric Exercise Training: A Review of Hypothesized Mechanisms and Protocol Application in Persons with Hypertension.

According to the American Heart Association 116.4 million, or 46% of US adults are estimated to have hypertension. Although, traditional moderate intensity aerobic exercise training is associated with reducing blood pressure by 5-8 mmHg, barriers to this modality of exercise training exist. Thus, the purpose of this review is to evaluate the mechanisms and incorporation of isometric exercise training (IET) as an adjunctive mode of exercise in a population with HTN. Based upon the articles reviewed from the years 2000-2020 which incorporated IET and provided clear protocols lasting 4 or more weeks, meaningful reductions in blood pressure occurred following IET (SBP, -9.7 ± 3.3 mmHg; DBP, -4.8 ± 2.6 mmHg) which support the need to increase adoption of this exercise form into practice to help treat hypertension. Specifically, an IET program of 12-20 minutes per day, 3 times per week, could improve blood pressure reduction in those with hypertension. IET has the potential to produce significant and clinically meaningful blood pressure reductions and could serve as an adjunctive exercise modality alongside the established exercise prescription for those with hypertension.

Impact of Dietary Potassium Restrictions in CKD on Clinical Outcomes: Benefits of a Plant-Based Diet.

In patients with advanced-stage chronic kidney disease (CKD), progressive kidney function decline leads to increased risk for hyperkalemia (serum potassium > 5.0 or >5.5 mEq/L). Medications such as renin-angiotensin-aldosterone system inhibitors pose an additional hyperkalemia risk, especially in patients with CKD. When hyperkalemia develops, clinicians often recommend a diet that is lower in potassium content. This review discusses the barriers to adherence to a low-potassium diet and the impact of dietary restrictions on adverse clinical outcomes. Accumulating evidence indicates that a diet that incorporates potassium-rich foods has multiple health benefits, which may also be attributable to the other vitamin, mineral, and fiber content of potassium-rich foods. These benefits include blood pressure reductions and reduced risks for cardiovascular disease and stroke. High-potassium foods may also prevent CKD progression and reduce mortality risk in patients with CKD. Adjunctive treatment with the newer potassium-binding agents, patiromer and sodium zirconium cyclosilicate, may allow for optimal renin-angiotensin-aldosterone system inhibitor therapy in patients with CKD and hyperkalemia, potentially making it possible for patients with CKD and hyperkalemia to liberalize their diet. This may allow them the health benefits of a high-potassium diet without the increased risk for hyperkalemia, although further studies are needed.

Correction: The effect of exercise on blood pressure in chronic kidney disease: A systematic review and meta-analysis of randomized controlled trials.

[This corrects the article DOI: 10.1371/journal.pone.0211032.].

Supervised Exercise Intervention and Overall Activity in CKD.

INTRODUCTION: Patients are often instructed to engage in multiple weekly sessions of exercise to increase physical activity. We aimed to determine whether assignment to a supervised exercise regimen increases overall weekly activity in individuals with chronic kidney disease (CKD). METHODS: We performed a secondary analysis of a pilot randomized 2 × 2 factorial design trial examining the effects of diet and exercise (10%-15% reduction in caloric intake, 3 supervised exercise sessions/wk, combined diet restriction/exercise, and control). Activity was measured as counts detected by accelerometer. Counts data were collected on all days for which an accelerometer was worn at baseline, month 2, and month 4 follow-up. The primary outcome was a relative change from baseline in log-transformed counts/min. Generalized estimating equations were used to compare the primary outcome in individuals in the exercise group and the nonexercise group. RESULTS: We examined 111 individuals randomized to aerobic exercise or usual activity (n = 48 in the exercise group and n = 44 controls). The mean age was 57 years, 42% were female, and 28% were black. Median overall adherence over all time was 73%. Median (25th, 75th percentile) counts/min over nonsupervised exercise days at months 2 and 4 were 237.5 (6.5, 444.4) for controls and 250.9 (7.7, 529.8) for the exercise group (P = 0.74). No difference was observed in the change in counts/min between the exercise and control groups over 3 time points (ß [fold change], 0.96, 95% confidence interval [CI], 0.91, 1.02). CONCLUSION: Engaging in a supervised exercise program does not increase overall weekly physical activity in individuals with stage 3 to 4 CKD.

Comparing the Changes in Blood Pressure After Acute Exposure to Tai Chi and Walking.

Hypertension is a major health concern throughout the United States and is a major cause of cardiovascular disease. The purpose of this study was to compare the responses of Tai Chi and walking on measures of central and peripheral cardiac mechanisms when controlling for exercise intensity. Fifteen hypertensive subjects (2 males, 13 females; age = 20.7 ± 3.77 years; body fat = 24.26 ± 10.27%) participated in Tai Chi (TC) and walking (WK) for 30 minutes on non-consecutive days. Central systolic (CSBP) and diastolic blood pressure (CDBP), augmentation index (Alx), pulse pressure (PP), heart rate (HR), and brachial systolic (BSBP) and diastolic blood pressure (BDBP) were measured prior to exercise and following exercise every 10 minutes for a total of 60 minutes in a seated position. There were no significant differences between the two exercise forms. CSBP decreased 10 minutes after exercise in both exercise types (TC = 6.63 ± 3.258 mmHG; WK = 7 ± 4.144 mmHG p < 0.05), and 40 minutes after exercise in both exercise types (TC = 6.07 ± 3.33 mmHG; WK = 8.2 ± 3.15 mmHG, p < 0.05) compared to the initial measurement. BSBP also decreased in both exercise forms following 10 min of rest (TC = 6.99 ± 3.776 mmHG; WK = 8.8 ± 3.20 mmHG p = 0.05), and 40 min (TC = 8.46 ± 3.07 mmHG; WK = 8.87 ± 3.87 mmHG, p < 0.05) when compared to the initial resting measurement. Central aortic pressure exhibits a post exercise hypotensive (PEH) effect similar to that of peripheral blood pressure. Both Tai Chi and walking elicited similar PEH effects on systolic blood pressure in hypertensive individuals.