Effects of 12 weeks combined aerobic and resistance exercise on heart rate variability in type 2 diabetes mellitus patients

Whey Protein Supplementation in Older Adults With Type 2 Diabetes Undergoing a Resistance Training Program: A Double-Blind Randomized Controlled Trial

BACKGROUND/OBJECTIVE

This study aims to analyze the effect of whey protein (WP) supplementation on glycemic control, muscle strength, quality of life, and body composition in older adults with non-insulin-dependent diabetes undergoing a resistance training program.

METHODS

A double-blind, placebo-controlled, randomized study was carried out with older adults with Type 2 diabetes. Body composition, food intake, muscle strength, glycemic profile, markers of renal function, cardiopulmonary capacity, and quality of life were evaluated. Older adults were randomized into a supplementation group with 33 g of WP consumed twice a week on days of resistance training for 12 weeks supplemented group and a placebo group.

RESULTS

In total, 39 older adults were randomized into two groups, 19 in the supplement group and 20 in the placebo group. Both groups showed improvement in muscle strength, with the WP group failing to exceed that of the control group. WP supplementation slightly increased blood urea compared with the placebo group (p = .05), but values remained within normal limits. The group that used WP showed a small improvement in mental health, according to the 12-Item Short-Form Health Survey questionnaire, but without clinically important improvements.

CONCLUSION

Both groups showed improvements in muscle strength and mass, regardless of supplementation, showing that resistance exercises performed twice a week can contribute to the nonprogression of sarcopenia in older adults with Type 2 diabetes. More studies are needed to determine the safe and effective amount of supplementation to improve muscle strength without renal impairment in older adults with diabetes.

Exercise Effects on Autonomic Nervous System Activity in Type 2 Diabetes Mellitus Patients over Time: A Meta-Regression Study

BACKGROUND

Diabetic autonomic neuropathy is a common complication of type 2 diabetes mellitus (T2DM), especially in patients with long-term, poorly controlled diabetes. This study investigates the effects of exercise on autonomic nervous system activity in T2DM patients over time.

METHODS

A literature review using MEDLINE, Embase, Cochrane Library, Scopus, and PubMed identified studies assessed via heart rate variability. Papers were categorized into three groups: immediate effects (within 60 min), short-term effects (2-3 months), and long-term effects (over 4 months).

RESULTS

Nine articles with 161 T2DM patients were included in the meta-analysis. RMSSD changes after exercise were -4.3 (p = 0.227), 8.14 (p < 0.001), and 4.17 (p = 0.002) for the immediate, short-term, and long-term groups, respectively. LF/HF ratio changes were 0.21 (p = 0.264), -3.04 (p = 0.102), and -0.05 (p = 0.006) for the respective groups. Meta-regression indicated age, male gender, and exercise duration were associated with increased RMSSD, with coefficients of 2.36 (p = 0.001), 13.76 (p = 0.008), and 1.50 (p = 0.007), respectively. Age positively correlated with the LF/HF ratio, with a coefficient of 0.049 (p = 0.048).

CONCLUSIONS

Regular exercise (≥3 times per week) for over 2 months increases parasympathetic activity in T2DM patients, while sympathetic activity decreases significantly after 4 months. Further study is needed to validate these findings.

The impact of exercise modalities on blood glucose, blood pressure and body composition in patients with type 2 diabetes mellitus

BACKGROUND

Physical activity has been recommended as an important non-pharmacological therapeutic strategy for the management of type 2 diabetes mellitus (T2DM). The aim of this study was to investigate the effects of 12 weeks of strength, aerobic, and a combination of aerobic and resistance training on blood glucose level, blood pressure, and body composition in patients with T2DM.

METHODS

From Debremarkos referral hospital, 40 subjects with T2DM (mean age 42.45 years, 29 men, 11 women) were randomly assigned to one of three intervention groups or the control group. The following variables were measured: body mass index (BMI), fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), and body fat percentage (BFP). Paired sample T-test and one-way ANCOVA were applied whilst controlling for diet, gender, and age.

RESULTS

All intervention groups showed improvement in a mean difference of FBG - 13.03 (t =-5.55, df = 39, p < 0.001), SBP - 21.63 mmHg - 17.6 mmHg (t =-6.51, df = 39, p < 0.001), DBP - 11.86 mmHg (t = -5.47, df = 39, p < 0.001) and BFP - 9.14 (t = -7.49, df = 39, p < 0.001). There was a significant difference in mean BMI reduction when diet, gender, and age were controlled in a one-way ANCOVA (F (3, 33) = 11.79, p < 0.001), SBP (F (3, 33) = 13.383, p < 0.001), DBP (F (3, 33) = 7.830, p < 0.001), FBG (F (3, 33) = 6.337, p < 0.001), BFP (F (3, 33) = 24.29, p < 0.001) between the exercise intervention groups and control group. Additionally, the estimated marginal means indicate that the combined strength and aerobic exercise intervention group experienced the greatest improvements.

CONCLUSION

Body composition, blood pressure, and fasting blood glucose were significantly lower in the combined (aerobic plus strength) treatment than in the individual treatment, indicating that the combined exercise intervention was more successful in altering these parameters.

The Effect of Exercise on Cardiovascular Autonomic Nervous Function in Patients with Diabetes: A Systematic Review

BACKGROUND

Diabetic neuropathy, including autonomic neuropathy, is a severe complication in patients with poorly controlled diabetes. Specifically, cardiovascular autonomic neuropathy (CAN) plays a significant prognostic role in cardiovascular morbidity and mortality. Exercise, an essential component of diabetes treatment, may have a therapeutic effect on patients with diabetes complicated by CAN. However, it remains unclear whether exercise has a therapeutic or protective effect in diabetes patients with CAN.

METHODS

The author conducted a systematic search of PubMed/MEDLINE, Embase, and The Cochrane Library, resulting in the identification of eight eligible randomized controlled trials for this review.

RESULTS

Exercise, including aerobic exercise combined with resistance training (RT), high-intensity interval training, and progressive RT, has shown a beneficial effect on cardiac autonomic function (CAF) in patients with type 2 diabetes, as measured by heart rate variability, heart rate recovery, and baroreflex sensitivity. However, most studies had low quality. Moreover, there were no relevant studies examining the effect of exercise on CAF in older patients, patients with poorly controlled diabetes, and patients with type 1 diabetes.

CONCLUSIONS

Exercise has the potential to manage patients with CAN by balancing sympathetic and parasympathetic nervous system functions; however, further studies are warranted in the future.

Heart rate variability after bariatric surgery: The add-on value of exercise

PURPOSE

To assess the impact of bariatric surgery and an added supervised exercise training programme on heart rate variability (HRV) in patients with severe obesity.

METHODS

Fifty-nine patients who underwent bariatric surgery were randomised in the post-operative period to a 12-week supervised exercise training programme (moderate intensity combination aerobic/resistance exercise training programme) or a control group. Indices of HRV including time-domain, spectral-domain, and nonlinear parameters were measured preoperatively, and at 3, 6, and 12 months.

RESULTS

After the surgical procedure, both groups improved anthropometric parameters. Type 2 diabetes, hypertension, and dyslipidemia resolutions were similar between groups. Total body weight loss at 6 and 12 months were also comparable between groups (6 months: 28 ± 6 vs. 30 ± 6%; 12 months: 38 ± 9 vs. 38 ± 10%; control vs. intervention group respectively). Bariatric surgery improved HRV parameters at 12 months compared to the pre-operative values in the intervention group: standard deviation of R-R interval (SDNN) (156.0 ± 46.4 vs. 122.6 ± 33.1 ms), low frequency (LF) (6.3 ± 0.8 vs. 5.8 ± 0.7 ms²), and high frequency (HF) (5.1 ± 0.8 vs. 4.7 ± 0.9 ms²) (all p<0.001). For the control patients, similar improvements in SDNN (150.0 ± 39.4 vs. 118.8 ± 20.1 ms), LF (6.1 ± 0.9 vs. 5.7 ± 0.8 ms²), and HF (5.0 ± 0.9 vs. 4.7 ± 0.9 ms²) were obtained (all p<0.001). However, there was no add-on impact of the supervised exercise training programme on HRV after 12 months (p>0.05 for all HRV parameters).

CONCLUSION

Bariatric surgery is associated with an improvement in HRV. A supervised exercise training programme in the post-operative period did not modulate further the benefits of bariatric surgery regarding HRV parameters.

Effects of Virtual Reality Exercise Program on Blood Glucose, Body Composition, and Exercise Immersion in Patients with Type 2 Diabetes

BACKGROUND

This study is a preliminary study to examine the effect of a virtual reality exercise program (VREP) on type 2 diabetes patients.

METHOD

This is a randomized controlled trial for patients with type 2 diabetes (glycated hemoglobin ≥ 6.5%), diagnosed by a specialist. The virtual reality environment was set up by attaching an IoT sensor to an indoor bicycle and linking it with a smartphone, enabling exercise in an immersive virtual reality through a head-mounted display. The VREP was implemented three times a week, for two weeks. The blood glucose, body composition, and exercise immersion were analyzed at baseline, and two weeks before and after the experimental intervention.

RESULT

After VREP application, the mean blood glucose (F = 12.001 p < 0.001) and serum fructosamine (F = 3.274, p = 0.016) were significantly lower in the virtual reality therapy (VRT) and indoor bicycle exercise (IBE) groups than in the control group. There was no significant difference in the body mass index between the three groups; however, the muscle mass of participants in the VRT and IBE groups significantly increased compared with that of the control (F = 4.445, p = 0.003). Additionally, exercise immersion was significantly increased in the VRT group compared with that in the IBE and control groups.

CONCLUSION

A two week VREP had a positive effect on blood glucose, muscle mass, and exercise immersion in patients with type 2 diabetes, and is highly recommended as an effective intervention for blood glucose control in type 2 diabetes.

Cardiac autonomic activity, endothelial function and physical fitness in type 2 diabetic patients

Objective: To investigate the association between cardiac autonomic activity, endothelial function, and physical fitness in patients with type 2 diabetes mellitus (T2DM). Methods: Twenty-seven patients with T2DM were studied, with a mean age of 57 ± 9 years and a mean disease duration of 7.4 ± 5 years. The assessment of physical fitness was performed using the Shuttle Walking Test (SWT), cardiac autonomic modulation by heart rate variability (HRV), and endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery through ultrasound imaging. Results: The main finding of this study was that some HRV indices (SDNN, RMSSD, and HF) were significantly correlated with endothelial function in individuals with T2DM, with R values between 0.51 and 0.57 (p < 0, 05), for all relationships. Additionally, an association was found between the distance covered in the SWT and the basal diameter of the brachial artery (R = 0.59; p = 0.01). Conclusion: Our data demonstrate that some HRV indices are associated with DMF, indicating an interaction between these two systems. Furthermore, our findings suggest a correlation between physical fitness and endothelial function in individuals with T2DM.

Effects of walking in individuals with prehypertension and stage 1 hypertension in India: a randomised controlled trial

Background/Aims

Physical activity, such as walking, is a cheap approach with a low risk of injury that can be used in daily life. The aim of this study was to determine the effects of low impact aerobic exercise training on resting blood pressure in patients with prehypertension and stage 1 hypertension specifically for people in India.

Methods

A total of 63 sedentary adults with prehypertension and stage 1 hypertension participated in the study. All sedentary adults were randomly allocated to either the study group (aerobic training) (n=30) or the control group (n=33). Those in the study group walked for 30 minutes, three times a week for 8 weeks at an intensity of 60–75% of their target heart rate. The control group received no training but followed their usual prescribed medication and diet. The primary outcomes of systolic blood pressure and diastolic blood pressure were measured at the end of every 2 weeks for 8 weeks. Secondary outcomes of pulse pressure, mean arterial pressure and pulse rate were calculated.

Results

Significant changes in various outcome measures in the study group were noted (systolic blood pressure=7.30 mmHg (95% confidence interval [CI] 2.14 to 3.00; P=0.001); diastolic blood pressure=6.50 mmHg (95% CI 1.23 to 4.04; pulse pressure=0.000; mean arterial pressure=6.77 mmHg (95% CI 1.46 to 3.84; P=0.000) and pulse rate=6.90 bpm (95% CI 1.73 to 3.43; P=0.000) when compared with those in the control group, who had non-significant changes.

Conclusions

The findings of the present study concluded that aerobic exercise training improves blood pressure.

Diagnostic Tools, Biomarkers, and Treatments in Diabetic polyneuropathy and Cardiovascular Autonomic Neuropathy

The various manifestations of diabetic neuropathy, including distal symmetric sensorimotor polyneuropathy (DSPN) and cardiovascular autonomic neuropathy (CAN), are among the most prevalent chronic complications of diabetes. Major clinical complications of diabetic neuropathies, such as neuropathic pain, chronic foot ulcers, and orthostatic hypotension, are associated with considerable morbidity, increased mortality, and diminished quality of life. Despite the substantial individual and socioeconomic burden, the strategies to diagnose and treat diabetic neuropathies remain insufficient. This review provides an overview of the current clinical aspects and recent advances in exploring local and systemic biomarkers of both DSPN and CAN assessed in human studies (such as biomarkers of inflammation and oxidative stress) for better understanding of the underlying pathophysiology and for improving early detection. Current therapeutic options for DSPN are (I) causal treatment, including lifestyle modification, optimal glycemic control, and multifactorial risk intervention, (II) pharmacotherapy derived from pathogenetic concepts, and (III) analgesic treatment against neuropathic pain. Recent advances in each category are discussed, including non-pharmacological approaches, such as electrical stimulation. Finally, the current therapeutic options for cardiovascular autonomic complications are provided. These insights should contribute to a broader understanding of the various manifestations of diabetic neuropathies from both the research and clinical perspectives.

Cardiac Autonomic Modulation in Response to Three Types of Exercise in Patients with Type 2 Diabetic Neuropathy

Purpose

Physical exercise is necessary in the handling DM, but it is not distinct which kind of physical exercise can improve cardiac autonomic modulation in T2DM. The purpose of this study was to compare the effects of three different modalities of exercise (aerobic, resistant, and combined) on cardiac autonomic modulation as measured by HRV in patients with type 2 diabetic neuropathy.

Methods

The participants were 45 men (age: 55.24 ± 8.11 years, weight: 89.5 ± 13.4 kg, height: 171.85 ± 6.98 cm, duration of diabetes: 12.51 ± 6.46 years) with type 2 diabetic neuropathy who were clinically free from signs and symptoms of cardiovascular disease. Participants were randomly assigned to one of four groups: aerobic-training (n = 11), dynamic resistant-training (n = 11), Combined-training (n = 11), or a non-exercise control group (n = 12). The exercise groups performed aerobic and resistant exercise for 25-45 min per day, 3-5 times per week for 12 weeks. Anthropometrics, biochemical markers (FBS, HbA1c, Lipid Profile, and Insulin), and heart rate variability in the exercise laboratory and under ambulatory conditions by 3-channel ECG digital Holter recorder were examined.

Results

All time and frequency-domain HRV parameters (except LF power) were significantly improved in the exercise groups, compared with the control group (p < 0.05). SDNN, rMSSD, and HF power were boosted, LF power was not different, and the LF/HF ratio decreased after versus before exercise training, independent of exercise modality. HbA1c in aerobic and resistant-training groups, and insulin and LDL in the resistant-training group were decreased after exercise training (p < 0.05).

Conclusions

Exercise training, independent of modality, in patients with type 2 diabetic neuropathy who were clinically free of the cardiovascular disease cause to significant progress in cardiovascular autonomic function assessed by HRV via enhancing cardio-vagal and reducing cardio-sympathetic tone.

A 16-Week Home-Based Progressive Resistance Tube Training Among Older Adults With Type-2 Diabetes Mellitus: Effect on Glycemic Control

Research has proven that aerobic exercise improves glucose homeostasis among patients with type 2 diabetes mellitus (T2DM). Elastic resistance (tube or band) is suggested as a good alternative for home-based strength training among older adults including those with T2DM due to its low cost, simplicity, portability, and versatility. This study aimed to measure the effects of 16-week home-based progressive resistance training (PRT), using a resistance tube on glucose homeostasis and cardiovascular risk factors among older adults with T2DM. A total of 70 participants aged 61.68 (5.50) years with T2DM were assigned to the intervention (n = 35) and control (n = 35) groups in this quasi-experimental trial. The intervention group underwent 16 weeks of home-based PRT using a resistance tube. Significant improvements in HbA1c (-1.34% point, p < 0.001), fasting blood glucose (-1.30 mmol/L, p < 0.001), and systolic blood pressure (-1.42 mmHg, p < 0.05) were observed after 16 weeks of intervention. However, no significant changes were observed in lipid profile, diastolic blood pressure, resting heart rate, and ankle-brachial index. The finding suggests that 16 weeks of home-based PRT using a resistance tube has the potential to improve glycemic control and reduce systolic blood pressure among older adults with T2DM and caused no adverse events.

Effect of exercise training on heart rate variability in type 2 diabetes mellitus patients: A systematic review and meta-analysis

Background

Cardiac autonomic neuropathy is a common complication of type 2 diabetes mellitus (T2DM), that can be measured through heart rate variability (HRV)–known to be decreased in T2DM. Physical exercise can improve HRV in healthy population, however results are under debate in T2DM. We conducted a systemic review and meta-analysis to assess the effects of physical exercise on HRV in T2DM patients.

Method

PubMed, Cochrane, Embase, and ScienceDirect databases were searched for all studies reporting HRV parameters in T2DM patients before and after exercise training, until September 20th 2020, without limitation to specific years. We conducted random-effects meta-analysis stratified by type of exercise for each of the HRV parameters: RR–intervals (or Normal to Normal intervals–NN), standard deviation of RR intervals (SDNN), percentage of adjacent NN intervals varying by more than 50 milliseconds (pNN50), root mean square of successive RR-intervals differences (RMSSD), total power, Low Frequency (LF), High Frequency (HF) and LF/HF ratio. Sensitivity analyses were computed on studies with the highest quality.

Results

We included 21 studies (9 were randomized) for a total of 523 T2DM patients: 472 had an exercise training and 151 were controls (no exercise). Intervention was endurance (14 studies), resistance (2 studies), endurance combined with resistance (4 studies), and high intensity interval training (HIIT) (4 studies). After exercise training, all HRV parameters improved i.e. an increase in SDNN (effect size = 0.59, 95%CI 0.26 to 0.93), RMSSD (0.62, 0.28 to 0.95), pNN50 (0.62, 0.23 to 1.00), HF (0.58, -0.16 to 0.99), and a decrease in LF (-0.37, -0.69 to -0.05) and LF/HF (-0.52, -0.79 to -0.24). There were no changes in controls. Stratification by type of exercise showed an improvement in most HRV parameters (SDNN, RMSSD, pNN50, LF, HF, LF/HF) after endurance training, whereas mostly LF/HF was improved after both resistance training and HIIT. Supervised training improved most HRV parameters. Duration and frequency of training did not influence the benefits on HRV.

Conclusion

Exercise training improved HRV parameters in T2DM patients which may reflect an improvement in the activity of the autonomic nervous system. The level of proof is the highest for endurance training. Supervised training seemed beneficial.

Effect of Moderate- Versus High-Intensity Interval Exercise Training on Heart Rate Variability Parameters in Inactive Latin-American Adults: A Randomized Clinical Trial

Ramírez-Vélez, R, Tordecilla-Sanders, A, Téllez-T, LA, Camelo-Prieto, D, Hernández-Quiñonez, PA, Correa-Bautista, JE, Garcia-Hermoso, A, Ramírez-Campillo, R, and Izquierdo, M. Effect of moderate- versus high-intensity interval exercise training on heart rate variability parameters in inactive Latin-American adults: a randomized clinical trial. J Strength Cond Res 34(12): 3403-3415, 2020-We investigated the effect of moderate versus high-intensity interval exercise training on the heart rate variability (HRV) indices in physically inactive adults. Twenty inactive adults were randomly allocated to receive either moderate-intensity training (MCT group) or high-intensity interval training (HIT group). The MCT group performed aerobic training at an intensity of 55-75%, which consisted of walking on a treadmill at 60-80% of the maximum heart rate (HRmax) until the expenditure of 300 kcal. The HIT group ran on a treadmill for 4 minutes at 85-95% peak HRmax and had a recovery of 4 minutes at 65% peak HRmax until the expenditure of 300 kcal. Supine resting HRV indices (time domain: SDNN = SD of normal-to-normal intervals; rMSSD = root mean square successive difference of R-R intervals and frequency domain: HFLn = high-frequency spectral power; LF = low-frequency spectral power and HF/LF ratio) were measured at baseline and 12 weeks thereafter. The SDNN changes were 3.4 (8.9) milliseconds in the MCT group and 29.1 (7.6) milliseconds in the HIT group {difference between groups 32.6 (95% confidence interval, 24.9 to 40.4 [p = 0.01])}. The LF/HFLn ratio changes were 0.19 (0.03) milliseconds in the MCT group and 0.13 (0.01) milliseconds in the HIT group (p between groups = 0.016). No significant group differences were observed for the rMSSD, HF, and LF parameters. In inactive adults, this study showed that a 12-week HIT training program could increase short-term HRV, mostly in vagally mediated indices such as SDNN and HF/LFLn ratio power. Trial registration. ClinicalTrials.gov NCT02738385 https://clinicaltrials.gov/ct2/show/NCT01796275, registered on March 23, 2016.

Pilates Method Training: Functional and Blood Glucose Responses of Older Women With Type 2 Diabetes

Melo, KCB, Araújo, FdS, Cordeiro Júnior, CCM, de Andrade, KTP, and Moreira, SR. Pilates method training: Functional and blood glucose responses of older women with type 2 diabetes. J Strength Cond Res 34(4): 1001-1007, 2020-The objective of this study was to investigate the effect of 12 weeks of the Pilates method on the functional capacity (FC) and glycemic control of older women with type 2 diabetes (T2D). Twenty-two women with T2D were randomized into control (CONTROL: 67.5 ± 6.3 years; 154.7 ± 6.1 cm; 73.5 ± 6.1 kg) and Pilates (PILATES: 65.5 ± 5.5 years; 155.0 ± 4.5 cm; 66.2 ± 5.4 kg) groups, which held sessions of 60 minutes at a frequency of 3 times per week during 12 weeks. Blood glucose was measured before and after sessions in PILATES, as well as in moments of pre, rest, 4, 8, and 12 weeks of the PILATES and CONTROL interventions. The glycated hemoglobin (HbA1c) level before and after 12 weeks of the intervention was evaluated. The general index of the FC (GIFC) was obtained through a battery of tests for older patients with T2D. Analysis of variance detected differences in the GIFC for PILATES vs. CONTROL, respectively, in 4 weeks (30.3 ± 4.6 vs. 34.8 ± 4.9 seconds; p < 0.05), 8 weeks (29.2 ± 4.5 vs. 34.6 ± 4.9 seconds; p < 0.05), and 12 weeks (27.2 ± 4.0 vs. 35.3 ± 4.6 seconds; p < 0.05). PILATES presented a difference in postprandial glycemia pre- vs. 4 and 12 weeks (246.1 ± 58.5 vs. 219.9 ± 59.9 and 207.6 ± 49.1 mg·dl, respectively; p < 0.05), as well as in HbA1c pre- vs. 12 weeks (7.8 ± 1.0 vs. 6.7 ± 0.6%, respectively; p < 0.05). Differences in postprandial glycemia (p < 0.05) were found in PILATES before vs. after sessions, respectively, of 1st-12th (217.1 ± 49.1 vs. 157.9 ± 55.7 mg·dl), 13th-24th (204.5 ± 44.7 vs. 146.3 ± 44.5 mg·dl), and 25th-36th (214.3 ± 40.4 vs. 152.7 ± 52.0 mg·dl). A correlation between postprandial glycemia and GIFC after 12 weeks was detected (r = 0.37; p = 0.04). It is concluded that 12 weeks of the Pilates method induces improvement and relationship in the FC and glycemic control in older women with T2D.

Effect of an Exergaming-Based Dance Training Paradigm on Autonomic Nervous System Modulation in Healthy Older Adults: A Randomized Controlled Trial

The purpose of this study was to determine if an exergaming-based dance training protocol can improve heart rate variability (HRV) in healthy older adults. A total of 20 healthy older adults (≥65 years old) were randomly assigned to two groups. The intervention group received an exergaming-based dance aerobic training for 6 weeks, while the control group received a 1-hr education on conventional physical exercises. Data obtained from HRV analysis pre- (Week 0) and postintervention (Week 7) consisted of high-frequency power, low- and high-frequency ratio, and root mean square of differences and percentage of adjacent RR intervals with a difference of duration greater than 50 ms values. HRV was assessed during rest and during a 6-min walk test. In addition, the YMCA submaximal cycle ergometer test was used to acquire estimated maximal O2 consumption pre- and postintervention. After the training, the intervention group showed significant improvement in HRV high-frequency power, root mean square of differences, and percentage of adjacent RR intervals with a difference of duration greater than 50 ms values in both rest and 6-min walk test conditions compared with the control group. Similarly, the intervention group showed higher maximal O2 consumption compared with the control group after the training. Our results support the effectiveness of an exergaming-based dance aerobic training on improving cardiac autonomic control in aging.

Cardiac Autonomic Neuropathy in Obesity, the Metabolic Syndrome and Prediabetes: A Narrative Review

Cardiac autonomic neuropathy (CAN) is a major complication of type 1 and type 2 diabetes mellitus (T1DM and T2DM). The increased morbidity, cardiovascular and all-cause mortality associated with CAN is established from numerous epidemiological studies. However, CAN is increasingly recognised in people with prediabetes (pre-DM) and the metabolic syndrome (MetS) with a reported prevalence up to 11% and 24% respectively. CAN is associated with components of MetS including hypertension and obesity, predating hyperglycaemia. The aetiology of CAN is multifactorial and there is a reciprocal relationship with insulin resistance and MetS. Obstructive sleep apnoea (OSA) is also associated with CAN possibly through MetS and an independent mechanism. An estimated global prevalence of the impaired glucose tolerance (IGT) form of pre-DM of 587 million people by 2045 means CAN will become a major clinical problem. CAN is independently associated with silent myocardial ischaemia, major cardiovascular events, myocardial dysfunction and cardiovascular mortality. Screening for CAN in pre-DM using risk scores with analysis of heart rate variability (HRV) or Sudoscan is important to allow earlier treatment at a reversible stage. The link between obesity and CAN highlights the therapeutic potential of lifestyle interventions including diet and physical activity to reverse MetS and prevent CAN. Weight loss achieved using these dietary and exercise lifestyle interventions improves the sympathetic and parasympathetic HRV indices of cardiac autonomic function. Further research is needed to identify high-risk populations of people with pre-DM or obesity that might benefit from targeted pharmacotherapy including metformin, sodium/glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide 1 (GLP-1) analogues. Bariatric surgery also improves HRV through weight loss which might also prevent CAN in severe obesity. This article reviews the literature on CAN in obesity, pre-DM and MetS, to help determine a rationale for screening, early intervention treatment and formulate future research questions in this highly prevalent condition.

Effectiveness of Exercise Intervention in Reducing Body Weight and Glycosylated Hemoglobin Levels in Patients with Type 2 Diabetes Mellitus in Korea: A Systematic Review and Meta-Analysis

BACKGROUND

This study aimed to assess the effectiveness of exercise intervention in reducing body weight and glycosylated hemoglobin (HbA1c) level in patients with type 2 diabetes mellitus (T2DM) in Korea.

METHODS

Cochrane, PubMed, Embase, KoreaMed, KMbase, NDSL, KCI, RISS, and DBpia databases were used to search randomized controlled trials and controlled clinical trials that compared exercise with non-exercise intervention among patients with non-insulin-treated T2DM in Korea. The effectiveness of exercise intervention was estimated by the mean difference in body weight changes and HbA1c level. Weighted mean difference (WMD) with its corresponding 95% confidence interval (CI) was used as the effect size. The pooled mean differences of outcomes were calculated using a random-effects model.

RESULTS

We identified 7,692 studies through literature search and selected 23 articles (723 participants). Compared with the control group, exercise intervention (17 studies) was associated with a significant decline in HbA1c level (WMD, -0.58%; 95% CI, -0.89 to -0.27; I²=73%). Although no significant effectiveness on body weight was observed, eight aerobic training studies showed a significant reduction in body weight (WMD, -2.25 kg; 95% CI, -4.36 to -0.13; I²=17%) in the subgroup analysis.

CONCLUSION

Exercise significantly improves glycemic control; however, it does not significantly reduce body weight. Aerobic training can be beneficial for patients with non-insulin-treated T2DM in Korea.

Sports therapy and recreation exercise program in type 2 diabetes: randomized controlled trial, 3-month follow-up

BACKGROUND

A sports therapy program in type 2 diabetes helps in glucose control, but little is known how a long-term structured exercise intervention affects the parameters in this disease. Our aim was to measure the impact of a 24-week-long sports therapy program in type 2 diabetes on the concentration of glucose in blood, body composition, and physical fitness level.

METHODS

In this prospective longitudinal study, 208 type II diabetic patient (80 male, 128 female, aged: 61±6.86 years) were selected and randomly assigned to a control or an intervention group. The intervention group took part in a sports therapy and recreation sports program for 6 months. Taking into account the rules of training theory and physiotherapy, fitness material of exercising (aerobics, resistance training, muscle strengthening, stretching) and outdoor elements were used during the 3-month sports program, after which it became a 3-month recreation exercise program. In the control group, there was no intervention.

RESULTS

The intervention group showed significant decrease in concentration of glucose in blood (mean differences [MD]:-3.23; Confidence Interval [CI] lowest: -3.50; CI highest: -2.95]; P<0.01), weight (MD: -1.68; [-0.82, -0.52] P=0.01), BMI (MD: -0.37; [-0.82; 0.08]; P=0.01), body fat percentage (MD:-1.74; [-2.15, -1.34]; P=0.05) and visceral fat (MD:-0.37; [-0.67, -0.07; P=0.01); right (MD: 5.33; [4.98, 5.68]; P<0.01) and left arm curl (MD: 5.23; [4.87, 5.60]; P<0.01) test, chair stand test (MD: 2.95; [2.65, 3.25]; P=0.00) and the 6-minute walk test (MD: 111.21; [101.12; 121.31]; P<0.01) showed significant improvement.

CONCLUSIONS

A 24-week-long sports therapy program is a successful intervention for improving parameters affected by type 2 diabetes.

Heart Rate Variability following Combined Aerobic and Resistance Training in Sedentary Hypertensive Women: A Randomised Control Trial

Objective

To investigate the effect of combined aerobic and resistance training (CART) on heart rate variability in sedentary, hypertensive women.

Participants

A total of twenty-eight hypertensive (Stage 1 and 2) sedentary women (Age 40.54 ± 4.2 yrs; Height 155.14 ± 5.4 cm; Weight 70.96 ± 10.2 kg; BMI 29.6 ± 4.4; Duration of HTN: 6.43 ± 2.5 yrs) were recruited for the study.

Methods

Participants were randomly assigned to either the CART group that performed combined aerobic and resistance exercise of moderate intensity [aerobic exercise 50–80% of HR_max (maximum heart rate) and resistance exercises at 50–80% of 1 Repetition Maximum (RM)], 5 times/week for 4 weeks, or to the control group that followed conventional treatment without any supervised exercise intervention.

Main outcome measures

Resting blood pressure was measured and standard heart rate variability (HRV) indices were calculated using time domain (SDNN, pNN50, RMSSD) and frequency domain (LFnu, HFnu, LF/HF and TP) analysis.

Results

CART group demonstrated an increase in HFnu, TP, SDNN, and RMSSD, (p < 0.05) along with a significant decrease in LFnu, LF/HF ratio, systolic blood pressure, and diastolic blood pressure (p < 0.05).

Conclusion

CART showed significant improvement in HRV parameters indicating vagal dominance in middle-aged hypertensive women. Therefore, exercise training in combined form (aerobic and resistance) may be incorporated in the management programs of the patients suffering from hypertension in order to augment improvement in their cardiac autonomic control.

Exercise training and cardiac autonomic function in type 2 diabetes mellitus: A systematic review

Cardiac autonomic neuropathy (CAN) is a common complication of type 2 diabetes mellitus (T2DM). It has been found to independently predict all cause and cardiovascular disease (CVD) mortality. It remains unclear whether exercise training could improve autonomic control in T2DM patients. The purpose of this study was to systematically review the effects of exercise training on cardiac autonomic function in T2DM patients. Electronic databases (MEDLINE, CENTRAL, PEDro, Scopus and Web of science) were systematically searched to retrieve relevant evidence. Clinical trials administering exercise training for at least 4 weeks and examining either heart rate variability (HRV), baroreflex sensitivity (BRS), heart rate recovery (HRR) as outcome measures were eligible. Eighteen articles were found to be relevant and were then assessed for characteristics and quality. Fifteen studies out of 18 found that exercise training leads to positive improvements in autonomic function of T2DM patients. Exercise participation enhances cardiac autonomic function of type 2 diabetics and therefore should be implemented in their management programs.

Cardiorespiratory Fitness and Cardiac Autonomic Function in Diabetes

PURPOSE OF REVIEW

This review summarizes the current knowledge on the relationship of physical activity, exercise, and cardiorespiratory fitness (CRF) with cardiovascular autonomic neuropathy (CAN) based on epidemiological, clinical, and interventional studies.

RECENT FINDINGS

The prevalence of CAN increases with age and duration of diabetes. Further risk factors for CAN comprise poor glycemic control, dyslipidemia, abdominal obesity, hypertension, and the presence of diabetic complications. CAN has been also linked to reduced CRF. We recently showed that CRF parameters (e.g., maximal oxidative capacity or oxidative capacity at the anaerobic threshold) are associated with cardiac autonomic function in patients recently diagnosed with type 1 or type 2 diabetes. Exercise interventions have shown that physical activity can increase cardiovagal activity and reduce sympathetic overactivity. In particular, long-term and regularly, but also supervised, performed endurance and high-intense and high-volume exercise improves cardiac autonomic function in patients with type 2 diabetes. By contrast, the evidence in those with type 1 diabetes and also in individuals with prediabetes or metabolic syndrome is weaker. Overall, the studies reviewed herein addressing the question whether favorably modulating the autonomic nervous system may improve CRF during exercise programs support the therapeutic concept to promote physical activity and to achieve physical fitness. However, high-quality exercise interventions, especially in type 1 diabetes and metabolic syndrome including prediabetes, are further required to better understand the relationship between physical activity, fitness, and cardiac autonomic function.

Physical Exercise Improves Heart Rate Variability in Patients with Type 2 Diabetes: A Systematic Review

PURPOSE OF REVIEW

The aim of the present systematic review is to provide an up-to-date analysis of the research on the effects of exercise programs on heart rate variability (HRV) in individuals with type 2 diabetes mellitus (T2DM). An electronic search of the literature (PubMed, PEDro and Web of Science) was performed. "HRV", "heart rate variability", "exercise", "physical" and "diabetes" were the terms used for article retrieval. Lastly, 15 articles were selected. PRISMA methodology was employed and data were extracted according to the PICOS approach.

RECENT FINDINGS

Although HRV is not routinely measured in the management of T2DM, it is an important measure due to its relation with mortality and diabetic neuropathy. Physical exercise has become a therapy for T2DM, because it improves physical fitness and functional capacity, enhances metabolic control and insulin sensitivity, reduces inflammatory markers and neuropathy symptoms and can increase the regenerative capacity of cutaneous axons, slowing or preventing neuropathy progression. However, it is not clear to what extent physical exercise can improve HRV in this population. Participation in the 15 selected studies was similar in men and women (48.01% men and 51.99% women). All the intervention programs included aerobic training, and it was complemented by strength training in four studies. Duration of physical exercise sessions ranged between 30 and 75 min, the frequency being between 2 and 7 days/week. Statistically significant improvements in groups with diabetes, relative to baseline, were observed in nine studies. More than 3 days per week of aerobic training, complemented by strength training, during at least 3 months seems to improve HRV in T2DM. Weekly frequency might be the most important factor to improve HRV. These aspects could help to design better programs based in scientific evidence, incorporating HRV as an important variable associated with diabetic neuropathy and mortality.

Synergistic effect of energy drinks and overweight/obesity on cardiac autonomic testing using the Valsalva maneuver in university students

BACKGROUND

Obesity and caffeine consumption may lead to autonomic disturbances that can result in a wide range of cardiovascular disorders.

OBJECTIVES

To determine autonomic disturbances produced by the synergistic effects of overweight or obesity (OW/OB) and energy drinks.

DESIGN

Cross-sectional, analytical.

SETTING

Physiology department at a university in Saudi Arabia.

SUBJECTS AND METHODS

University students, 18-22 years of age, of normal weight (NW) and OW/OB were recruited by convenience sampling. Autonomic testing by the Valsalva ratio (VR) along with systolic and diastolic blood pressure, pulse pressure, and mean arterial blood pressure were measured at baseline (0 minute) and 60 minutes after energy drink consumption.

MAIN OUTCOME MEASURE(S)

Autonomic disturbance, hemodynamic changes.

RESULTS

In 50 (27 males and 23 females) subjects, 21 NW and 29 OW/OB, a significant decrease in VR was observed in OW/OB subjects and in NW and OW/OB females at 60 minutes after energy drink consumption. Values of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure were also significantly higher in OW/OB and in females as compared to NW and males. BMI was negatively correlated with VR and diastolic blood pressure at 60 minutes.

CONCLUSION

Obesity and energy drinks alter autonomic functions. In some individuals, OW/OB may augment these effects.

LIMITATIONS

Due to time and resource restraints, only the acute effects of energy drinks were examined.