The effect of low intensity bicycle exercise on the insulin-induced glucose uptake in obese patients with type 2 diabetes

Skeletal Muscle Hyperemia: A Potential Bridge Between Post-exercise Hypotension and Glucose Regulation

For both healthy individuals and patients with type 2 diabetes (T2D), the hemodynamic response to regular physical activity is important for regulating blood glucose, protecting vascular function, and reducing the risk of cardiovascular disease. In addition to these benefits of regular physical activity, evidence suggests even a single bout of dynamic exercise promotes increased insulin-mediated glucose uptake and insulin sensitivity during the acute recovery period. Importantly, post-exercise hypotension (PEH), which is defined as a sustained reduction in arterial pressure following a single bout of exercise, appears to be blunted in those with T2D compared to their non-diabetic counterparts. In this short review, we describe research that suggests the sustained post-exercise vasodilation often observed in PEH may sub-serve glycemic regulation following exercise in both healthy individuals and those with T2D. Furthermore, we discuss the interplay of enhanced perfusion, both macrovascular and microvascular, and glucose flux following exercise. Finally, we propose future research directions to enhance our understanding of the relationship between post-exercise hemodynamics and glucose regulation in healthy individuals and in those with T2D.

Exercise Intensities as Factors of Metabolic Outcomes in Type 2 Diabetes: A Systematic Review

Exercise is effective to prevent and treat type 2 diabetes, although currently underutilized. This review analyzes the metabolic response to exercise performance at various intensities in individuals with type 2 diabetes. These findings provide insight into the development of safe and efficacious exercise prescriptions and education. We conducted a systemic review of the literature to examine the association of various exercise protocols with metabolic outcomes in type 2 diabetes. Between 1984 and 2018, 29 studies were categorized per exercise mode and intensity levels according to the American College of Sports Medicine standards. The most consistent improvement was found in HbA1c following moderate- to high-intensity exercise—post-exercise fasting glucose improved to a lesser extent. Low-intensity exercise improved HOMA-IR (homeostasis model assessment for insulin resistance) levels. Glucose and HbA1c improved most following interval compared with continuous exercise, irrespective of intensity. A comparison of high-intensity exercise with moderate-intensity exercise demonstrated few differences in HbA1c, fasting glucose, fasting insulin, and HOMA-IR. Irrespective of exercise intensity, HbA1c improvements were observed, suggesting a delayed progression to diabetes-related complications. Initial low-intensity exercise, with increased quantities when feasible, will contribute to metabolic improvements. The variability in methodology and measurement contributed to inconsistent outcomes; additional research with larger samples sizes is warranted.

Objectively measured sedentary time and associations with insulin sensitivity: Importance of reallocating sedentary time to physical activity

OBJECTIVE

The aim of this study is to quantify associations between objectively measured sedentary time and markers of insulin sensitivity by considering allocation into light-intensity physical activity or moderate- to vigorous-intensity physical activity (MVPA).

METHODS

Participants with an increased risk of impaired glucose regulation (IGR) were recruited (Leicestershire, United Kingdom, 2010-2011). Sedentary, light-intensity physical activity and MVPA time were measured using accelerometers. Fasting and 2-hour post-challenge insulin and glucose were assessed; insulin sensitivity was calculated by HOMA-IS and Matsuda-ISI. Isotemporal substitution regression models were used. Data were analysed in 2014.

RESULTS

508 participants were included (average age=65years, female=34%). Reallocating 30min of sedentary time into light-intensity physical activity was associated a 5% (95% CI 1, 9%; p=0.024) difference in Matsuda-ISI after adjustment for measured confounding variables. Reallocation into MVPA was associated with a 15% (7, 25%; p<0.001) difference in HOMA-IS and 18% (8, 28%; p<0.001) difference in Matsuda-ISI. Results for light-intensity physical activity were modified by IGR status with stronger associations seen in those with IGR.

CONCLUSIONS

Reallocating sedentary time into light-intensity physical activity or MVPA was associated with differences in insulin sensitivity, with stronger and more consistent associations seen for MVPA.

Effect of a single bout of moderate exercise on glucose uptake in type 2 diabetes mellitus

BACKGROUND AND PURPOSE

Hypoglycemia during exercise is a serious problem in diabetic patients during cardiac rehabilitation, whereas normal subjects rarely experience hypoglycemia. Inappropriate glucose uptake by working muscles may be responsible. However, the precise characteristics of glucose uptake during exercise have not been fully studied. We have investigated the effect of acute exercise on glucose uptake in diabetic patients.

METHODS

Nine type 2 diabetic patients (age, 57 ± 6 years; HbA1c, 7.7 ± 1.3%) performed exercise at an intensity of anaerobic threshold for 15 min. Glucose utility was determined using euglycemic hyperinsulinemic clamp technique. Glucose infusion rate (GIR) was calculated throughout the exercise and recovery session.

RESULTS

Average GIR at rest was 3.4 ± 1.6 mg/(kg(BW)min). Fifteen minutes after starting exercise, it increased significantly (6.6 ± 2.4, p < 0.001). Thirty minutes after cessation of exercise, GIR decreased significantly (4.8 ± 1.9, p < 0.05) compared with peak value. Increase in GIR was greater as BMI or body fat ratio became greater (r=0.608 and 0.475). There was a weak correlation (r=0.344) between HbA1c and GIR improving ratio (GIR during exercise x 100/GIR at rest).

CONCLUSIONS

Glucose uptake was revealed to augment significantly within 15 min after the commencement of exercise. This improvement was more obvious in patients with greater body weight, fat accumulation, and poorer diabetic control.

After Pregnancy Complicated by Diabetes: Postpartum Care and Education

The postpartum period in women with pregestational or gestational diabetes allows the physician and mother to switch from intensive medical and obstetric management into a proactive and preventive mode, and to jointly develop a reproductive health plan. The woman's individual needs regarding contraception and breastfeeding, an appropriate diet to achieve healthy weight goals, the medical management of diabetes, daily exercise, and future pregnancy planning must be considered. Essential is the active participation of the woman, who, through education, gains an understanding of the far-reaching effects her active participation will have on her subsequent health, her newborn child's health, and possibly that of her future children.

Mechanical horseback riding improves insulin sensitivity in elder diabetic patients

The present study was undertaken to analyze the acute and chronic effects of exercise on insulin sensitivity in elder diabetic patients using a horseback riding therapeutic equipment (Joba). The acute effects of exercise were examined by means of a single session of Joba riding that lasted for 30 min. The average glucose infusion rates (GIR) before and during exercise were regarded as an index of the insulin action in peripheral tissues by the euglycemic clamp. The chronic effects of exercise were studied by training the elder diabetic patients for 12 weeks using the Joba apparatus. The insulin sensitivity was determined pre- and post-training by a 90 min euglycemic clamp. In the acute study, average GIR during exercise was significantly higher than pre-exercise (7.8+/-0.4 versus 5.2+/-0.3 mg kg(-1)min(-1), P<0.01) and average GIR during recovery decreased to almost the same levels of pre-exercise (5.0+/-0.4 mg kg(-1)min(-1); P<0.01). The 12-week training resulted in a significant increase in the steady-state GIR (from 5.2+/-0.3 to 7.4+/-0.8 mg kg(-1)min(-1); P<0.05). The steady-state GIR after 12 weeks of detraining returned to pre-training levels (5.3+/-0.5 mg kg(-1)min(-1); P<0.05). In elder diabetic patients, mechanical horseback riding enhances the insulin-induced glucose uptake.

Effects of a controlled program of moderate physical exercise on insulin sensitivity in nonobese, nondiabetic subjects

OBJECTIVE

To study the effect of a moderate, aerobic physical exercise program on insulin resistance and its accompanying metabolic changes in a group of healthy, middle-age, nonobese subjects, without modifying oxygen consumption and body weight.

DESIGN

The inclusion of subjects was carried out among volunteers from the health personnel of our center, who complied with the inclusion criteria.

PARTICIPANTS

Twelve subjects (age 30-60 years, 5 females), nonsmokers, body mass index (BMI) <27 kg/m2 and fasting plasma glucose <6.1 mmol/L.

INTERVENTIONS

Insulin resistance was assessed using the Bergmann minimal model modified with insulin, and basal and maximum metabolic rate were measured with standard methods. All subjects completed a 2-month program of aerobic exercise using the American College of Sports Medicine guidelines, consisting of aerobic exercise of moderate, regular, and continual intensity (3 times per week), with a duration of 45 to 50 minutes per session.

RESULTS

Following controlled exercise, no significant differences in BMI, waist-hip ratio, blood pressure, lipids, free fatty acids, and leptin plasma values were observed. Plasma glucose and insulin values decreased significantly (-0.37 mmol/L and -16.5 pmol/L, respectively). Insulin sensitivity showed an increase of 2.1 x 10(-4) mU L(-1) min(-1) (P = 0.001). Basal and maximum metabolic rate showed no significant differences after the exercise program.

CONCLUSIONS

Moderate aerobic exercise increases insulin sensitivity in nonobese, nondiabetic subjects in the absence of significant changes in weight, BMI, waist-hip ratio, lipid profile, and oxygen consumption.

High intensity exercise enhances platelet reactivity to shear stress and coagulation during and after exercise

Platelets play a crucial role in the pathogenesis of acute cardiac events, such as angina, myocardial infarction and sudden death. It is believed that regular low-intensity exercise can reduce, while high-intensity exercise may provoke acute cardiac events. The aim of the present study was to investigate the effect of acute exercise both at low and high intensities on the ventilatory threshold (VT), platelet reactivity and coagulation before and after exercise. Platelet reactivity and coagulation were measured under flow condition, using native blood, by hemostatometry. Seven healthy young men (age: 20-29 years) performed bicycle ergometer exercise for 30 min at intensities of 90% (Ex-VT90% or approximately 55% VO(2max)) and 130% (Ex-VT130% or 80% VO(2max)) of individual VT. Blood cell counts, hematocrit, blood lactic acid and plasma catecholamine levels were slightly but significantly increased after Ex-VT90% and markedly after Ex-VT130% after 30 min exercise. Subsequent to the exercise, the elevated blood cell counts decreased to the resting levels both at Ex-VT90% and at Ex-VT130%. Platelet reactivity to shear stress and dynamic coagulation were significantly enhanced immediately and 30 min after Ex-130%VT. In contrast, no significant changes occurred in those of Ex-90%VT. The present study suggests that high-intensity exercise-induced platelet hyperreactivity and hypercoagulable state may pose an increased risk for acute, sometimes fatal cardiac event. On the other hand, our findings support the view that low-intensity exercise does not present a risk of thrombosis.

Clinical evaluation and management of metabolic and morphologic abnormalities associated with human immunodeficiency virus

In recent years, a spectrum of metabolic and morphologic alterations has emerged among patients infected with human immunodeficiency virus (HIV) receiving antiretroviral treatment. Changes observed include insulin resistance, dyslipidemia, abdominal and dorsocervical fat accumulation, and fat depletion in the extremities and in the face. The health consequences of these changes are not well understood but may include increased risk for diabetes, heart disease, and stroke. Therefore, clinicians that treat patients with HIV need current, practical information on management strategies and interventions for patients with manifestations of HIV-associated lipodystrophy. Literature is reviewed on the health consequences of insulin resistance, dyslipidemia, and alterations in body fat distribution in non-HIV populations to gain perspective on how such abnormalities might affect HIV-infected patients. We also suggest treatments and strategies to manage metabolic and morphologic changes in patients with HIV.

Postpartum care of the woman with diabetes

The postpartum period in women with diabetes or GDM allows both the physician and mother to relax from the intensive medical and obstetric management that has permitted, in most cases, a successful and joyous outcome. The role of the physician, however, must switch to a proactive and preventive mode to formulate a reproductive health plan for women with diabetes and GDM. The plan should be individualized to address glycemic management and surveillance, nutritional management, contraception prescription, future pregnancy planning, and lifestyle changes. Essential to the development of a reproductive health plan is the active participation of the patient, who through education gains an understanding of the far-reaching effects her active participation will have on her subsequent health and possibly on that of her future children.