chapter 37: exercise prescription in patients with...

Copyright © 2010 American College of Sports Medicine

Chapter 37: Exercise Prescription in Patients with Diabetes American College of Sports Medicine. (2010). ACSM's resource manual for guidelines for exercise testing and prescription (6th ed.). New York: Lippincott, Williams and Wilkins


Epidemiology and Pathophysiology of Diabetes

• Definition: abnormal glucose metabolism resulting from defects in insulin release, action, or both

– Higher prevalence in nonwhites in the U.S.

– Many related complications increase morbidity and mortality

– Complications related to extended hyperglycemia and blood glucose (BG) fluctuations and affect macrovascular, microvascular, and neural processes

• Types of Diabetes

– Type 1 Diabetes Mellitus (T1DM)

• Young onset

– Type 2 Diabetes Mellitus (T2DM)

• Typically older onset, but becoming more common in younger individuals

– Gestational Diabetes Mellitus (GDM)

• Onset during or soon after pregnancy


Clinical Features of Diabetes

• Diagnosis: based on established criteria

• Glucose regulation (aka, glycemic control): the maintenance of blood glucose in a normal range with a goal of reducing the risk of secondary complications

– BG regulation is primary focus after diagnosis

– Performed with medications, diet, and exercise

– Glycemic control assessed by glycosylated hemoglobin (aka, HbA1c) values

• Nondiabetic range = 4%-6%

• Goal is ≤7%


Clinical Features of Diabetes

• Glucose regulation: normally controlled by hepatic release and dietary intake and by peripheral uptake of glucose

– Diabetes often requires artificial glucose regulation

• Insulin injections or continuous subcutaneous insulin infusion (i.e., insulin pump)

• Oral hypoglycemic agents

• β-cell stimulants for insulin release

• Drugs to improve insulin sensitivity

• Drugs that abate intestinal absorption of carbohydrates


Treatment• Best initiated by a multidisciplinary team of specialists:

– Physician – Diabetes educator – Registered dietician– Exercise physiologist

• Keys to adequate treatment: treatment should focus on controlling blood glucose and risk factors for diabetes-related complications

– Control and treat blood glucose: intensive self blood glucose monitoring and oral drugs or exogenous insulin (or both)

– Lose weight and improve blood lipid profile: balanced diet and regular physical activity/exercise

– Enhance fitness: regular physical activity/exercise

– Smoking cessation

– Self-manage: diabetes self-management education


Acute and Chronic Exercise-Related Physiologic Responses in Diabetes

• Acute exercise:

– Improves insulin sensitivity

– Facilitates glucose uptake

– Aids in glucose homeostasis

• Chronic Exercise:

– Improves cardiovascular function

– Improves blood lipids and lipoproteins

– Lowers BP

– Decreases body mass, fat mass, and body fat distribution

– Affects fat-free mass (maintain or increase)

– Improves insulin sensitivity

– Improves glucose control (T2DM only)

– Increases metabolism

– Enhances postprandial thermogenesis


Exercise Prescription in Diabetes • Screening

– Pre-exercise glucose levels

• If below 100 mg/dL, then no exercise until rises above 100 mg/dL

• If hyperglycemic, need to ensure no symptoms or ketones (typically produced with values >250-300 mg/dL) before allowing exercise

– Screening for vascular and neurologic complications, including silent ischemia and retinopathy

– Assessment for cardiovascular risk factors and metabolic syndrome

– Determine if pre-exercise training stress test is indicated


Exercise Prescription in Diabetes

• Aerobic Training Exercise Prescription

• Precautions of Aerobic Training

– Consider supervision in all patients for initial training

– Supervision strongly suggested for those early post diabetes-related event or surgery

– Warm-up and cool-down very important in this population

– Consider modality based on individual patient, focusing on body weight, mobility, balance, peripheral neuropathy, and condition of feet with respect to sores and ulcers

– Monitor pre- and postexercise blood glucose, especially for the first several exercise sessions, to avoid hypoglycemia

– Require stress test if performing vigorous exercise



• Resistance Training Exercise Prescription

• Precautions of resistance training

– May need to consider not performing due to uncontrolled high blood pressure

• Avoid Valsalva maneuver

– Often contraindicated if retinopathy

• Seek physician confirmation



• Flexibility Exercise Prescription

• Precautions of flexibility training

– Appropriate modification(s) of stretches due to joint limitations, obesity, or pregnancy restrictions in the case of GDM should be made.

– Avoid ballistic stretching due to increased risk of musculoskeletal injury.



• Exercise prescription for cardiac clientele

– Encourage participation in cardiac rehabilitation.

– Hypoglycemic symptoms may be reduced in those with neuropathies or taking a β-blocker.

– Stress test is often needed to detect ischemia (reduced ability to feel angina) and for accurate heart rate–based prescription (autonomic neuropathy).

– Aerobic, resistance, and flexibility training are similar to the patient without cardiac disease.


Exercise Recommendations for Specific Diabetes-Related Complications

• Autonomic Neuropathy

– Affects the involuntary functions of the body, including the cardiac, vascular, GI, and genitourinary systems

– Cardiac effects can lead to:

• Elevated resting heart rate

• Reduced heart rate reserve

• Inability to sense angina

• Postexercise hypotension

• Thermoregulatory dysfunction

• Prone to dehydration

• Hypoglycemia unawareness



• Peripheral Neuropathy

– Affects the extremities, especially the lower legs and feet

• Loss of sensation in or desensitized feet

• Prone to ulcers and wounds

• Poor wound healing

• Increased incidence of lower limb amputation

– Need to check feet daily

– Watch injuries from overstretching and loss of balance/falls

– Non–weight-bearing exercise modes indicated when severe



• Nephropathy

– When excessive urinary protein is present (microalbuminuria >30 and <300 mg·dL–1)

– Hypertension increases risk

– Goal is to delay onset of end-stage renal disease (ESRD)

– Focus:

• Low- to moderate-intensity aerobic and resistance exercise

• Proper hydration strategies

• Avoidance of activities that cause excessive elevation in BP



• Retinopathy

– Nonproliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR)

– Requires tight glucose and blood pressure control

– Can get a 15% improvement in aerobic capacity with low- to moderate-intensity exercise training

chapter 37: exercise prescription in patients with...

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