Autonomic dysfunction of overweight combined with low muscle mass

Effects of Preoperative Sarcopenia-Related Parameters on Cardiac Autonomic Function in Women with Obesity Following Bariatric Surgery: A One-Year Prospective Study

OBJECTIVES

Investigate changes in blood pressure (BP) and heart rate variability (HRV) in women with and without sarcopenia-related parameters who underwent bariatric surgery (BS) during a one-year follow-up.

SUBJECTS AND METHODS

Women were separated into obesity (OB, n = 20) and women with obesity displaying sarcopenia-related parameters (SOP, n = 14) and evaluated before BS and 3, 6, and 12 months after BS. SOP was defined as low handgrip strength (HS) and/or low appendicular skeletal mass adjusted for weight (ASM/wt × 100, %) in the lowest quartile of the sample. ASM/wt × 100, % and HS were significantly lower in SOP than OB over a one-year follow-up of BS (p < 0.05).

RESULTS

There was a reduction in diastolic BP, heart rate (HR), SDHR, LF, and the LF/HF ratio (p < 0.05) and an increase in the HF band in both groups during the follow-up period (p < 0.05). SOP women had reduced root mean square differences of successive RR intervals (RMSSD) and HF band and an increased LF band and SD2/SD1 ratio compared to the OB group during the one-year follow-up (p < 0.05). ASM/wt × 100, % was negatively associated with the LF band (r = -0.24, p = 0.00) and positively associated with the HF band (r = 0.22, p = 0.01). Conversely, HS had no association with LF (r = -0.14, p = 0.09) and HF (r = 0.11, p = 0.19). ASM/wt × 100, % and HS were negatively associated with the LF/HF ratio (p < 0.05).

CONCLUSIONS

Women who underwent BS had an improved HRV over a one-year follow-up. However, the improvement in HRV variables was less pronounced in women with low muscle mass and/or HS during the follow-up period.

Effects of Vibration Training on Weight Loss and Heart Rate Variability in the Obese Female College Students

Objective

The present study examined the effects of a 12-week whole-body vibration training (WBVT) regimen on heart rate variability (HRV) and body composition in the obese female college students.

Methods

Participants were assigned to either the WBVT (n = 17) or obese control group (n = 19). The students in the WBVT group conducted a 12-week (5 times per week and 30 min per time) exercise protocols (30 to 40 Hz of frequency and 4 mm of amplitude), and the obese control group did not perform regular physical training during 12 weeks of study. Then, body composition (body weight, BMI, body fat, body fat percentage; trunk fat mass, muscle mass, MM) and HRV (time domain and frequency domain index) were measured in all subjects before and after WBVT intervention.

Results

(1) After 12-week WBVT intervention, body fat mass, trunk fat mass, and body fat percentage significantly decreased and muscle mass increased in the WBVT group (P < 0.01, respectively); there was no significant change in body weight and BMI (P > 0.05, respectively). (2) After 12-week WBVT intervention, LFn, LF/HF, and HR significantly decreased (P < 0.05, P < 0.01), R-R interval and RMSSD significantly increased (P < 0.01, respectively), and there was no significant difference in HFn (P > 0.05). Nevertheless, there was no significant change before and after the test in body composition and HRV in the obese control group (P > 0.05, respectively). (3) After 12-week WBVT intervention, compared with the obese control group, body fat mass, body fat percentage, trunk fat mass, and LF/HF significantly decreased (P < 0.05, P < 0.01), muscle mass, and RMSSD increased (P < 0.05) in the WBVT group; but there were no significant difference in other indicators (P > 0.05) between the obese control group and WBVT group. (4) The reduction of body fat percentage before and after the WBVT intervention are positively correlated with the reduction in the LFn and LF/HF (r = 0.542, r = 0.504; P < 0.05, respectively) and negatively correlated with the increase in the RMSSD (r = −0.514, P < 0.05), and the reduction of trunk fat mass are positively correlated with the reduction in the LF/HF (r = 0.540, P < 0.05).

Conclusion

The results indicate that WBVT improves HRV and body composition in obese female college students, and the reduction in body fat percentage and trunk fat mass are associated with a shift in cardiac autonomic regulation towards vagal dominance and improve sympathetic-vagus balance after WBVT intervention. In conclusion, WBVT may be a feasible treatment to improve cardiac autonomic function and body composition.

Relationship between blood pressure response during hemodialysis and exercise tolerance or heart rate recovery measured using cardio-pulmonary exercise testing in maintenance hemodialysis patients

Background

This study investigated the association between the blood pressure response during hemodialysis (HD) and exercise tolerance or heart rate recovery (HRR) measured with cardiopulmonary exercise testing (CPX).

Methods

The study enrolled 23 patients who had been undergoing 4-h regular maintenance HD. The maximum workload (Loadpeak), peak oxygen uptake (VO2peak), workload and oxygen uptake at the anaerobic threshold (LoadAT and VO2AT, respectively), and HRR were measured with CPX. The average systolic blood pressure during HD (SBPav) was measured, and the number of times the SBP was less than 100 mmHg was determined in the 2-week period after CPX.

Results

The SBPav showed a significant correlation with LoadAT (r = 0.46) and Loadpeak (r = 0.43, p < 0.05). The number of times the SBP was less than 100 mmHg showed a significant correlation with the HRR (r = − 0.44, p < 0.05).

Conclusion

Exercise intolerance and HRR in HD patients may be associated with blood pressure instability during HD.

Reference Values for Skeletal Muscle Mass - Current Concepts and Methodological Considerations

Assessment of a low skeletal muscle mass (SM) is important for diagnosis of ageing and disease-associated sarcopenia and is hindered by heterogeneous methods and terminologies that lead to differences in diagnostic criteria among studies and even among consensus definitions. The aim of this review was to analyze and summarize previously published cut-offs for SM applied in clinical and research settings and to facilitate comparison of results between studies. Multiple published reference values for discrepant parameters of SM were identified from 64 studies and the underlying methodological assumptions and limitations are compared including different concepts for normalization of SM for body size and fat mass (FM). Single computed tomography or magnetic resonance imaging images and appendicular lean soft tissue by dual X-ray absorptiometry (DXA) or bioelectrical impedance analysis (BIA) are taken as a valid substitute of total SM because they show a high correlation with results from whole body imaging in cross-sectional and longitudinal analyses. However, the random error of these methods limits the applicability of these substitutes in the assessment of individual cases and together with the systematic error limits the accurate detection of changes in SM. Adverse effects of obesity on muscle quality and function may lead to an underestimation of sarcopenia in obesity and may justify normalization of SM for FM. In conclusion, results for SM can only be compared with reference values using the same method, BIA- or DXA-device and an appropriate reference population. Limitations of proxies for total SM as well as normalization of SM for FM are important content-related issues that need to be considered in longitudinal studies, populations with obesity or older subjects.

Whole-body vibration training in obese subjects: A systematic review

OBJECTIVE

(i) to determine the outcomes of whole-body vibration training (WBVT) on obese individuals, and the intervention settings producing such effects; (ii) identify potential improper or harmful use of WBVT.

DESIGN

Systematic review.

DATA SOURCES

Medline, Scopus, Web of Science, PEDro and Scielo until July 2018.

ELIGIBILITY CRITERIA

Full papers evaluating the effect of WBVT on body composition, cardiovascular status and functional performance in obese adults. Papers with PEDro score<4 were excluded.

STUDY APPRAISAL AND SYNTHESIS

Risk of bias and quality of WBVT reporting were assessed with PEDro scale (randomized controlled trials) or TREND checklist (non-randomized studies) and a 14-items checklist, respectively. Weighted acceleration, daily exposure and Hedges' adjusted g were computed.

RESULTS

We included 18 papers published 2010-2017. Typical interventions consisted in three sessions/week of exercises (squats, calf-raises) performed on platforms vibrating at 25-40 Hz (amplitude: 1-2 mm); according to ISO 2631-1:1997, daily exposure was "unsafe" in 7/18 studies. Interventions lasting ≥6 weeks improved cardiac autonomic function and reduced central/peripheral arterial stiffness in obese women; 10 weeks of WBVT produced significant weight/fat mass reduction, leg strength improvements as resistance training, and enhanced glucose regulation when added to hypocaloric diet. No paper evidenced losses of lean mass. Isolated cases of adverse effects were reported.

SUMMARY

To date, WBVT is a promising adjuvant intervention therapy for obese women; long-term studies involving larger cohorts and male participants are required to demonstrate the associated safety and health benefits. The therapeutic use of WBVT in the management of obese patients is still not standardised and should be supported by an extensive knowledge on the causality between vibration parameters and outcomes.

Association of physical capacity with heart rate variability based on a short-duration measurement of resting pulse rate in older adults with obesity

BACKGROUND

Obesity can limit physical capacity and lower physical activity levels in elderly people. Low physical activity levels may be mediated by autonomic dysfunction with decreased heart rate variability (HRV). However, the relationship between autonomic dysfunction and low physical capability remains unclear. This cross-sectional study investigated the association of low physical capability with HRV in older adults with obesity.

MATERIALS AND METHODS

We recruited 231 old man and 210 old women with a mean (range) age of 65.5 (51-78) and 62.9 (52-76) years, respectively. Physical capability was measured using mobility tasks, including functional reach, single-leg stance (SLS), gait speed (GS), timed up and go, and timed chair rise (TCR), and the scores on these tasks were merged and transformed into a global physical capability score (GPCS). HRV was measured using a 7-min resting pulse-based technique, and the time- and frequency-domain indices of HRV were obtained including standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences at rest (rMSSD), and high-frequency (HF) power. All HRV indices were natural log (ln) transformed for analysis. Participants were divided into high, moderate, and low physical-capability groups according to their physical performance. Multivariate analysis of covariance was performed to test differences in HRV indices among physical-capability groups with participants' characteristics serving as covariates. A stepwise regression model was established to identify the determinants of HRV indices. We used hierarchical regression analysis to identify the association of the GPCS with HRV indices.

RESULTS

In both men and women, the low physical-capability group exhibited significantly increased heart rate (P <0.05) and decreased HRV in terms of a decreased ln[SDNN] (P <0.001), ln[rMSSD] (P <0.05) and ln[HF] (P <0.05), compared with the high physical-capability group. GS positively predicted ln[SDNN], whereas SLS, GS, and TCR were determinants of ln[HF], regardless of gender. The GPCS in older men and women independently accounted for 29.9% (P <0.001) and 23.7% (P <0.001), respectively, in variance in ln[SDNN].

CONCLUSIONS

A low physical-capability level is an independent determinant of decreased HRV in older adults with obesity.

HEART RATE VARIABILITY AND BODY COMPOSITION AS VO2MAX DETERMINANTS

ABSTRACT Introduction: The maximum oxygen consumption (VO2max) is the gold standard in the cardiorespiratory endurance assessment. Objective: This study aimed to develop a mathematical model that contains variables to determine the VO2max of sedentary people. Methods: Twenty participants (10 men and 10 women) with a mean age of 19.8±1.77 years were included. For each participant, body composition (percentage of fat and muscle), heart rate variability (HRV) at rest (supine and standing), and VO2max were evaluated through an indirect test on a cycloergometer. A multivariate linear regression model was developed from the data obtained, and the model assumptions were verified. Results: Using the data obtained, including percentage of fat (F), percentage of muscle (M), percentage of power at very low frequency (VLF), α-value of the detrended fluctuation analysis (DFAα1), heart rate (HR) in the resting standing position, and age of the participants, a model was established for men, which was expressed as VO2max = 4.216 + (Age*0.153) + (F*0.110) - (M*0.053) - (VLF*0.649) - (DFAα1*2.441) - (HR*0.014), with R2 = 0.965 and standard error = 0.146 L/min. For women, the model was expressed as VO2max = 1.947 - (Age*0.047) + (F*0.024) + (M*0.054) + (VLF*1.949) - (DFAα1*0.424) - (HR*0.019), with R2 = 0.987 and standard error = 0.077 L/min. Conclusion: The obtained model demonstrated the influence exerted by body composition, the autonomic nervous system, and age in the prediction of VO2max.

Development and validation of a Fall Risk Assessment Index for dialysis patients

BACKGROUND

Dialysis patients often have low physical performance due to uremic sarcopenia, protein energy wasting (PEW), and incidence intradialytic hypotension (IDH), which are indicated as risk factors for falling. The objective of this study was to develop a symptom-encompassing evaluation form to predict falls with high sensitivity for dialysis patients.

METHODS

A total of 251 patients who had been receiving maintenance hemodialysis therapy three times a week were enrolled in the study. Demographics, malnutrition and inflammatory status, dialytic therapeutic management situation, physical function and performance, and inquiries about falling were recorded. The Cox proportional hazards analysis evaluated the impact of falls. Calculated hazard ratios were converted to weighted scores, using approximate multiples of 0.5 and an evaluation form was created, which we called the Dialysis Fall Risk Index (DFRI). Kaplan-Meier survival analyses with the log-rank test and the Cox proportional hazard analysis were performed to evaluate the validity of the DFRI.

RESULTS

The DFRI consisted of seven items and a total of 12 points. The predictive validity of DFRI included hazard ratios for quartile 3 and 4 of 2.65 and 3.84, respectively, compared with quartile 1 as a reference point. The cut-off point of the DFRI showed the highest sensitivity and specificity among other screening indices.

DISCUSSION

The present study included the development of a new evaluation form that encompasses symptoms of end-stage kidney disease to predict falls in dialysis patients.

Heart Rate Variability in Children with Attention-Deficit/Hyperactivity Disorder: A Pilot Study

BACKGROUND

Attention deficit/hyperactivity disorder (ADHD) is a common childhood neuropsychiatric disorder. Autonomic nervous system plays a vital role in attention, self-regulation, emotional stability and social affiliation, which are affected in ADHD. The prefrontal cortex, which is vital for attention, motor control, emotional regulation and higher order autonomic control, is hypofunctional in ADHD. In addition, catecholamine dysregulation is there.

PURPOSE

We hypothesized that there is autonomic dysfunction: reduction in overall heart rate variability (HRV) and sympathovagal imbalance in children with ADHD.

METHODS

Study criteria were drug-naïve ADHD children who were 7-12 years of age of either gender who fulfilled DSM-IV criteria for ADHD and did not have any associated comorbid psychiatric/neurological/medical disorders. Two hundred and seventy ADHD children were screened out of which only 12 were found eligible and 10 participated. Sample size was 20 (cases = 10, age- and gender-matched healthy controls = 10). Short-term HRV of both time and frequency domains were assessed by recording lead II electrocardiogram after using Tell-Show-Do, a behavior shaping technique. Comparison between groups was done using Mann-Whitney and Wilcoxon test. Demographic variables like age, height, weight and body mass index were similar between groups.

RESULTS

Among time domain parameters, SD of all NN intervals, square root of the mean of the sum of squares of differences between adjacent NN intervals and percentage of count of number of pairs of adjacent NN intervals differing by more than 50 ms were reduced in ADHD group with p < 0.05. Among frequency domain parameters, total power was reduced in ADHD group with p < 0.05, high frequency power (HF) was reduced in ADHD group with p < 0.01 and low frequency power to HF ratio was higher in ADHD group with p < 0.01.

CONCLUSION

There is autonomic dysfunction in children with ADHD - reduction in overall HRV with sympathovagal imbalance with sympathetic dominance.