|
|
Mariana Lazo, M.D. and Mimi Huizinga, M.D.
02-06-2011
- Physical activity and exercise: bodily movements produced by the contraction of skeletal muscle that require energy expenditure beyond resting energy expenditure and improve one or more components of physical fitness.
- Physical fitness: includes cardiorespiratory fitness, muscular fitness and flexibility (see below).
- Classification of physical intensity: light (35-54% maximum heart rate); moderate (55-69% maximum heart rate); high (70 - 89% maximum heart rate).
- Maximum heart rate = 220 - age, preferably determined by graded exercise testing (GXT).
- Physical activity is an important element in the prevention and management of type 2 diabetes.
- Many beneficial effects of exercise, alone and in combination with diet, in diabetes (Thomas; Wasserman).
- Glycemic control: average A1c reduction of -0.8% after 130-270 minutes/week of exercise for 6 months (Snowling), within the range to promote significant reductions in microvascular, macrovascular and non-vascular complications (UKPDS).
- Body composition: exercise reduces body mass (average -5.1%) and body fat (average -15%). Aerobic exercise (below) affects body composition more than resistance training, although both are beneficial (Snowling).
- Risk factor control: improvement in hypertension (average reduction SBP -5.6 mmHg, DBP -5.5 mmHg), hyperlipidemia (triglycerides -26.6 mg/dl on average, HDL + 5.0 mg/dl on average), and obesity (Marwick; Snowling).
- Cardiovascular benefits: vascular structure and function (endothelial dysfunction and vascular distensibility), myocardial function and CAD (coronary artery disease) risk and mortality (Desai; Stewart).
- Psychological effects: improves quality-of-life and depression symptoms (Williamson)
-
Cardiac risk: ADA/ACSM 2011 recommendations: to consider ECG stress testing in individuals at high risk for CAD about to undergo moderate- to high- intensity exercise with age >40 years or age >30 years and 1) type 1 or 2 diabetes >10 years; 2) additional risk factor for CAD (hypertension, smoking, dyslipidemia); or 3) presence of microvascular complications (retinopathy or nephropathy). Any of the following regardless of age: 1) known or suspected CAD, stroke, and/or peripheral vascular disease; 2) autonomic neuropathy; or 3) advanced nephropathy with renal failure.
-
AHA/ ACC recommends GXT if one of the following criteria exists: 1) CAD and no stress test within past 2 years; 2): symptoms of chest discomfort or dyspnea; 3) clinical or laboratory evidence of peripheral artery disease (PAD) or cerebrovascular disease; 4) ECG evidence of infarction or ischemia; 5) objective of vigorous exercise program.
-
Non-cardiac risk factors: Hypoglycemia risk factors include: recurrent low glucose measurements, longer duration of diabetes, lower BMI, impaired hypoglycemia unawareness, insulin treatment and insulin secretagogues (e.g. sulfonylureas and meglitinides).
-
Peripheral arterial disease and foot care: Presence of PAD requires individualized supervised exercise program, and foot injury prevention strategies such as limiting exercise to walking speed, aquatic exercise or recumbent cycle ergometry, proper footwear and regular inspection of the feet.
-
Microvascular disease: Aerobic exercise or activities that results in a Valsalva maneuver is contraindicated in presence of proliferative retinopathy.
-
Severe peripheral neuropathy: increased risk of foot damage with exercise.
- Risk of skin ulceration and development of charcot joint.
-
General: Middle-aged patients may be deconditioned, with limited strength and flexibility and other comorbidities (e.g. obesity, osteoarthritis) that hinder engagement in any activity. Set an achievable goal: short with frequent periods of brisk activity instead of a single 30-minute session. Combination of aerobic with resistance training will increase endurance. Progressive increments: if sedentary, initiate at low level and gradually increase.
-
Frequency: Minimum 3 days/ week with no more than two consecutive days between bouts of aerobic exercise and at least 2-3 times weekly of resistance exercise on nonconsecutive days; more frequent exercise training maximizes both acute glucose-lowering effect and CAD benefits.
-
Intensity: Moderate intensity exercise has positive effects. Corresponds to approximately 40-60% of maximum aerobic capacity. Recommend vigorous-intensity exercise if tolerated and no contraindications.
-
Education: Instruct patients to identify atypical symptoms of ischemia, and adjust medications based on self-monitoring of blood glucose.
-
Warm-up: 5-10 min aerobic activity at low intensity and 5-10 min muscle stretching and cool down periods. Hydration: Before and during exercise, frequently and in amounts sufficient to compensate for losses. Diabetes identification bracelet or shoe tag. Proper foot care and nutrition before exercise.
-
Session duration: 150 minutes/week of moderate-intensity exercise or 90 min/week of high-intensity exercise each week. Each session should be minimum 10 minutes. Because of improved adherence and similar efficacy, 3 short sessions of 10 minutes may be preferable to a single 30 minutes session (Jakicic).
-
Program duration: Acute and chronic improvements in insulin resistance with physical activity. Changes in body composition usually require longer. Ideally, changes in lifestyle should be permanent.
-
Type: Aerobic exercise: Rhythmic, repeated, and continuous movements of the same large muscle groups for at least 10 min at a time (e.g.walking, bicycling, jogging, and swimming). Increases cardiorespiratory fitness and energy expenditure. Resistance exercise: Activities that use muscular strength to move a weight or work against a resistive load (e.g. weight lifting and exercise using weight machines). Increases muscular fitness and whole body glucose utilization. Includes 5-10 exercises involving the major muscle groups (upper body, lower body, core) and completion of 10-15 repetitions to near fatigue; slow progression over time to heavier weights that can only be lifted 8-10 times. Both types of exercise are important in diabetes; combination may offer greatest health benefits although milder forms (i.e. yoga) have mixed results.
-
Metabolic control before exercise: Avoid physical activity if fasting glucose >250 mg/dl and urinary ketones present; use caution if glucose is high even if no ketones. Ingest additional carbohydrate if glucose levels <100 mg/dl.
-
Blood glucose monitoring before and after exercise: Identify when changes in insulin or food intake are necessary. Learn the glycemic response to different exercises. This varies from patient to patient.
-
Reduction of insulin dose: Often need to reduce dose of rapid or short-acting insulin taken before exercise. 50% reduction is a common starting place. Titrate insulin reduction for each patient and for different types of exercise. Intense aerobic activity may require greater insulin reduction than resistance training. Persons on insulin and insulin secretagogues may be at higher risk of hypoglycemia and advised to supplement with carbohydrate as needed.
-
Food intake: For unplanned activity, increase carbohydrate consumption to avoid hypoglycemia. Have readily available carbohydrates during and after physical activity. Reduction of rapid or short-acting insulin is preferable to additional carbohydrate intake for planned activity.
-
Hypoglycemia: stop physical activity if hypoglycemic symptoms develop during exercise. Be aware of delayed hypoglycemic effect, 6-12 hours after exercise.
-
Hyperglycemia: in some patients, glucose may rise during resistance or intense aerobic exercise due to increased catecholamines but not as commom
- At least 2.5 hours/week of moderate to vigorous physical activity should be undertaken in high-risk adults to prevent type 2 diabetes.
- Higher physical activity levels may also reduce risk of developing gestational diabetes.
- The Diabetes Prevention Program demonstrated 58% reduced risk of developing diabetes in persons with prediabetes who underwent an intensive lifestyle program (Key studies in Diabetes Care: Prevention)
- Factors affecting adherence: perceived barriers and benefits, self-efficacy, motivation, social support, access, provider support, presence of depression or anxiety.
- Factors effective in improving long-term adherence: ongoing individual or group counseling, exercise consultation, group support and telephone counseling.
- Beneficial effects of exercise in diabetes are well documented and include: metabolic effects, risk factor control, cardiovascular benefits and psychological effects.
- Exercise prescription includes assessment of pre-exercise cardiac and non-cardiac risks, and a detailed program (duration, frequency, intensity and type of exercise).
- Encourage a combination of aerobic and resistance training.
- Aim to have at least 3 nonconsecutive days/week of training, minimum of 150 minutes/week of moderate-intensity exercise or 90 minutes/week of high-intensity exercise, and individual sessions lasting 10 minutes or more of aerobic exercise Recommendations for resistance exercise are 2 - 3 times per week.
- Presence of known cardiovascular disease is not an absolute contraindication to exercise but may necessitate a supervised cardiac rehabilitation program.
- Exercise training may even be undertaken during dialysis sessions.
- Persons with uncontrolled proliferative retinopathy should avoid activities that increase intraocular pressure and hemorrhage risk.
- Moderate walking will likely not increase risk of ulcerative disease in persons with peripheral neuropathy.
- Focus on developing self-efficacy in physical activity programs
- Encourage long-term exercise programs to achieve maximal benefits.
- Colberg SR, Sigal RJ, Fernhall B, et al.;
Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: joint position statement executive summary.;
Diabetes Care;
2010; Vol.
33; pp.
2692-6;
ISSN:
1935-5548;
PUBMED: 21115771
Rating:
Basis for recommendation
Comments:American Diabetes Association and American College of Sports Medicine joint position statement on exercise and type 2 diabetes.
- Marwick TH, Hordern MD, Miller T, et al.;
Exercise training for type 2 diabetes mellitus: impact on cardiovascular risk: a scientific statement from the American Heart Association.;
Circulation;
2009; Vol.
119; pp.
3244-62;
ISSN:
1524-4539;
PUBMED: 19506108
Rating:
Basis for recommendation
Comments:Most recent scientific statement of this topic from the American Heart Association.
|
|
