Increase in the heart rate variability with deep breathing in diabetic patients after 12-month exercise training.
ABSTRACT Autonomic neuropathy in diabetes leads to impaired regulation of blood pressure and heart rate variability (HRV), which is due to a shift in cardiac autonomic balance towards sympathetic dominance. Lower HRV has been considered a predictor of cardiac mortality and morbidity. Deep breathing test is a simple method to measure HRV and it provides a sensitive measure of cardiac autonomic function. The effect of long-term physical activity on HRV in type-2 diabetes mellitus is inconclusive. We aimed to evaluate the effects of regular physical exercise on HRV with deep breathing in type 2 diabetes (n = 105). Thirty normotensive diabetic patients and 25 hypertensive diabetic patients underwent physical exercise program for 12 months, and the other 50 patients (22 normotensive and 28 hypertensive diabetic patients) were considered the non-exercised group. Electrocardiogram was recorded during deep breathing and HRV was measured. Regular exercise significantly increased HRV in diabetic patients with and without hypertension. The degree of the increase in HRV was greater in hypertensive diabetic patients (p < 0.01) than in normotensive diabetic patients (p < 0.05). After exercise, glycosylated hemoglobin levels were decreased in both groups of diabetic patients. Moreover, the hypertensive diabetic patients showed a decrease (p < 0.05) in blood pressure after regular exercise. Thus, regular exercise training increases HRV, suggesting that there is a shift in the cardiac sympathovagal balance in favor of parasympathetic dominance in diabetic patients. Long-term physical training may be an effective means to reverse the autonomic dysregulation seen in type 2 diabetes.
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ABSTRACT: Regular exercise improves glucose control in diabetes, but the association of different exercise training interventions on glucose control is unclear. To conduct a systematic review and meta-analysis of randomized controlled clinical trials (RCTs) assessing associations of structured exercise training regimens (aerobic, resistance, or both) and physical activity advice with or without dietary cointervention on change in hemoglobin A(1c) (HbA(1c)) in type 2 diabetes patients. MEDLINE, Cochrane-CENTRAL, EMBASE, ClinicalTrials.gov, LILACS, and SPORTDiscus databases were searched from January 1980 through February 2011. RCTs of at least 12 weeks' duration that evaluated the ability of structured exercise training or physical activity advice to lower HbA(1c) levels as compared with a control group in patients with type 2 diabetes. Two independent reviewers extracted data and assessed quality of the included studies. Of 4191 articles retrieved, 47 RCTs (8538 patients) were included. Pooled mean differences in HbA(1c) levels between intervention and control groups were calculated using a random-effects model. Overall, structured exercise training (23 studies) was associated with a decline in HbA(1c) level (-0.67%; 95% confidence interval [CI], -0.84% to -0.49%; I(2), 91.3%) compared with control participants. In addition, structured aerobic exercise (-0.73%; 95% CI, -1.06% to -0.40%; I(2), 92.8%), structured resistance training (-0.57%; 95% CI, -1.14% to -0.01%; I(2), 92.5%), and both combined (-0.51%; 95% CI, -0.79% to -0.23%; I(2), 67.5%) were each associated with declines in HbA(1C) levels compared with control participants. Structured exercise durations of more than 150 minutes per week were associated with HbA(1c) reductions of 0.89%, while structured exercise durations of 150 minutes or less per week were associated with HbA(1C) reductions of 0.36%. Overall, interventions of physical activity advice (24 studies) were associated with lower HbA(1c) levels (-0.43%; 95% CI, -0.59% to -0.28%; I(2), 62.9%) compared with control participants. Combined physical activity advice and dietary advice was associated with decreased HbA(1c) (-0.58%; 95% CI, -0.74% to -0.43%; I(2), 57.5%) as compared with control participants. Physical activity advice alone was not associated with HbA(1c) changes. Structured exercise training that consists of aerobic exercise, resistance training, or both combined is associated with HbA(1c) reduction in patients with type 2 diabetes. Structured exercise training of more than 150 minutes per week is associated with greater HbA(1c) declines than that of 150 minutes or less per week. Physical activity advice is associated with lower HbA(1c), but only when combined with dietary advice.JAMA The Journal of the American Medical Association 05/2011; 305(17):1790-9. · 29.98 Impact Factor
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ABSTRACT: To review clinical trials that have prescribed exercise training in high-risk, ethnic populations with type 2 diabetes mellitus (T2DM) and delineate areas for future research. A systematic review using computerized databases was performed. The systematic review located nine trials, including four uncontrolled trials, and five randomized controlled trials (RCTs) that included 521 participants. Cohorts studied included African, Indian, Polynesian, Hispanic, Arabian, and Chinese peoples and interventions included aerobic training, resistance training or a combination thereof. Several trials documented improvements in HbA1c, insulin action, body composition, blood lipids and systolic and diastolic blood pressure. In general, a longer duration and greater frequency of training resulted in greater adaptation. Studies demonstrating no effect were generally limited by an inadequate intervention. There was evidence of differential training responses between Caucasians and non-Caucasians in two studies drawing such comparisons. Robust RCTs prescribing appropriate, targeted interventions and investigating relevant outcomes may be required to stimulate greater advocacy for exercise as a therapeutic adjunct for diabetes management in these populations. Investigations should be extended to other high-risk populations, particularly indigenous peoples who suffer an extreme burden of T2DM. Translation of research into clinical application should remain the overall objective.Diabetes research and clinical practice 02/2012; 97(2):206-16. · 2.74 Impact Factor
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ABSTRACT: Objective: Emerging adults often begin making independent lifestyle choices during college, yet the association of these choices with fundamental indicators of health and adaptability is unclear. The present study examined the relationship between health risks and neurocardiac function in college drinkers. Method: Heart rate variability (HRV) was assessed at baseline and in reaction to a paced breathing challenge in 212 college drinkers (53.8% women). Basal HRV served as a general indicator of health. Reactive HRV (during paced breathing) was used as a marker of an individual's adaptability to challenge. The relationship of HRV to alcohol use, cigarette use, exercise, sleep, and body mass index (BMI) was assessed. Results: Greater alcohol use and less exercise were associated with lower basal HRV. BMI was unrelated to basal HRV but was negatively associated with reactive HRV during the breathing challenge. Conclusions: High levels of alcohol use and lack of exercise are negative correlates of cardiovascular and general health, even in apparently healthy college drinkers. The negative relationship between BMI and reactive HRV suggests that overweight individuals have reduced ability to psychophysiologically adapt to challenges; understanding the temporal course of this relationship is needed. This study highlights the importance of examining HRV at baseline and in response to a challenge to capture the active neurocardiac processes that contribute to health and adaptive responding. The suppressive effects of health risks on HRV are modifiable; thus, HRV may be useful in evaluating the health benefits of lifestyle change and in promoting change behaviors in college drinkers. (J. Stud. Alcohol Drugs, 74, 787-796, 2013).Journal of studies on alcohol and drugs 09/2013; 74(5):787-96. · 1.68 Impact Factor