Week 5 - Diabetes - Type I, Type II and Gestational

Diabetes: Exercise for Metabolic and Mental Health Conditions

Introduction

• Exercise is a crucial element in diabetes care and preventing/delaying type II diabetes.
• Only 39% of adults with diabetes meet physical activity guidelines, compared to 58% of other adults.

Diabetes Mellitus

• A group of metabolic diseases characterized by insufficient insulin production or improper insulin use, leading to hyperglycemia.
• Insulin, produced by the pancreas, is essential for glucose uptake by skeletal muscles, adipose tissue, and the liver, which is vital for brain and nerve function.
• Elevated blood glucose increases the risk of cardiovascular (macrovascular) disease, microvascular diseases (retinopathy, nephropathy), and nerve damage (neuropathy).

Scope of Diabetes

• Asymptomatic individuals with diabetes and pre-diabetes face an increased risk of long-term health complications.
• Diabetes is the 7th leading cause of death in the United States.
• Mortality rates for people with diabetes are twice as high as those without diabetes of the same age.
• The economic impact of diabetes is significant, primarily due to long-term complications and hospitalizations.

Diabetes in Australia

• The prevalence of diabetes in Australia has risen from 3.3% in 2001 to 5.3% in 2022.
• Type 2 diabetes mellitus (T2DM) is the most common type, accounting for 87.6% of cases.
• Indigenous Australians are 2.9 times more likely to have diabetes than non-Indigenous Australians (12.6% vs. 4.3%).
• Other factors associated with higher diabetes rates:
  • Being born overseas
  • Living in a disadvantaged area
  • Living with a disability
  • Living alone
  • Being unemployed
  • Having a lower level of education

Pathophysiology

• Classification helps determine treatment, but diabetes can't always be clearly classified by type at diagnosis.

Type I Diabetes

• Two subgroups:
  • Immune-mediated
  • Idiopathic
• Immune-mediated diabetes (formerly known as juvenile-onset or insulin-dependent diabetes) accounts for 5-10% of diabetes cases.
• It's an autoimmune disease where the immune system attacks beta cells, leading to insulin deficiency; requires insulin injections or a pump.
• More frequent in childhood and adolescence but can occur at any age.
• Type I idiopathic diabetes has unknown causes, occurs in a small number of people (mostly of African or Asian ancestry), is strongly inherited, and lacks evidence of beta cell autoimmunity.

Type II Diabetes

• Formerly called adult-onset or non-insulin-dependent diabetes; affects 90-95% of people with diabetes.
• Onset typically after age 40, but increasingly seen in adolescents.
• Pathophysiology is complex and multifactorial; common features include insulin resistance in peripheral tissues and defective insulin secretion.
• Treatment options: lifestyle management (medical nutrition therapy and physical activity); oral agents, insulin, or other injectable medications; bariatric surgery (for BMI > 35).
• Ketoacidosis is rare.
• Genetic influence is present; offspring with one parent with T2DM have a 3.5-fold higher risk, and with two parents, a 6-fold higher risk.
• Obesity contributes significantly to insulin resistance; 80% of people with T2DM are overweight or obese at onset.
• Risk increases with age, lack of physical activity, history of gestational diabetes, hypertension, or dyslipidemia.

Gestational Diabetes

• Defined as "diabetes diagnosed in the second or third trimester of pregnancy that is not clearly either type I or type II diabetes."
• Usually diagnosed with OGTT at 24-28 weeks of pregnancy.
• Risk factors: family history, previous delivery of large birth weight (> 9lb / 4kg), obesity.
• Women with gestational diabetes have an increased risk of developing type II diabetes later in life; recommended lifelong screening every three years.
• Structured moderate physical exercise during pregnancy decreases the risk of gestational diabetes and is safe for mother and neonate.

Other Specific Types of Diabetes

• Certain diseases, injuries, infections, medications, or genetic syndromes can cause diabetes.
• This type may or may not require insulin treatment.

Acute Complications of Diabetes

• Hyperglycemia (high blood glucose)
• Hypoglycemia (low blood glucose)
• These complications must be quickly identified to ensure proper treatment.
• Manifestations of hyperglycemia: diabetes out of control, diabetic ketoacidosis, hyperosmolar non-ketotic syndrome.

Acute Complications - Hyperglycemia

• High blood glucose levels cause the kidneys to excrete glucose and water, leading to increased urine production and dehydration.
• Symptoms of high blood glucose levels include headache, weakness, and fatigue.
• Treatment includes drinking plenty of non-carbohydrate fluids, regular self-monitoring of blood glucose, and increased diabetes medications.
• Frequent high blood glucose levels damage organs over time, increasing the risk of chronic complications.

Acute Complications - Diabetic Ketoacidosis

• Occurs in patients with poorly controlled diabetes due to very low or absent effective insulin, more likely in type I diabetes.
• Ketones form due to the body's inability to use glucose effectively, leading to ineffective fat metabolism.
• A by-product of fat metabolism is ketone body formation by the liver, causing coma and death.
• Ketone levels in the blood are approximately 0.1 mmol/L in a person without diabetes and can be as high as 25 mmol/L in someone with diabetic ketoacidosis.
• Symptoms of ketoacidosis include abdominal pain, nausea, vomiting, rapid or deep breathing, sweet- or fruity-smelling breath.
• Exercise is contraindicated in anyone experiencing diabetic ketoacidosis.

Acute Complications - Hyperglycemic Hyperosmolar Non-Ketotic Syndrome

• Occurs in patients with type II diabetes when hyperglycemia is profound and prolonged.
• Most likely during illness or stress, in the elderly, or in undiagnosed individuals.
• Results in severe dehydration due to rising blood glucose levels, causing excessive urination; extreme dehydration leads to decreased mentation and possible coma.
• Exercise is contraindicated in anyone experiencing hyperglycemic hyperosmolar non-ketosis.

Acute Complications - Hypoglycemia

• A potential side effect of diabetes treatment; usually occurs when blood glucose levels drop below 65 mg/dL (3.6 mmol/L).
• May occur due to too much insulin, too little carbohydrate intake, missed meals, or excessive/poorly planned exercise.
• Can occur during exercise or hours to days later.
• Late-onset post-exercise hypoglycemia generally occurs following moderate- to high-intensity exercise lasting longer than 30 minutes; results from increased insulin sensitivity, ongoing glucose use, and physiological replacement of glycogen stores through gluconeogenesis.
• Patients should monitor blood glucose levels before and periodically after exercise.
• Symptoms of hypoglycemia are adrenergic (shakiness, weakness, sweating) and neuroglycopenic (headache, visual disturbances, mental dullness).

Acute Complications - Hypoglycemia Unawareness

• The inability to sense hypoglycemic symptoms; onset of neuroglycopenic symptoms before adrenergic warning symptoms.
• Prior exercise and prior hypoglycemia may blunt the normal adrenergic response.
• Tight control of blood glucose may lower the threshold for symptoms.
• Patients who have been in poor control may have symptoms associated with low blood glucose levels much higher than 3.6 mmol/L.
• Treatment: test blood glucose to confirm hypoglycemia and consume approximately 15 grams of carbohydrate.

Acute Complications - Treatment of Hypoglycemia

• Commercial products (glucose tablets or Glucojel jelly beans) allow a person to eat a precise amount of carbohydrate. Other sources include:
  • 1 cup of non-fat milk
  • ½ cup of orange juice
  • ½ can of regular soft drink
  • 6 – 7 Lifesavers
  • 2 tablespoons of raisins
  • 1 tablespoon of sugar, honey or corn syrup
• Wait 15 to 20 minutes to allow the symptoms to resolve and then re-check blood glucose levels to determine if additional carbohydrate is necessary.
• If the patient becomes unconscious because of hypoglycemia, an ambulance should be called, and glucagon should be administered.

Chronic Complications of Diabetes

• Diabetes is the leading cause of adult-onset blindness, non-traumatic lower limb amputation, and end-stage renal failure.
• People with diabetes are at two to four times the normal risk of heart disease and stroke.
• Chronic exposure to hyperglycemia is of primary importance in development, along with hypertension and hyperlipidemia.
• Intensive blood glucose control can reduce the risk of developing microvascular diabetic complications.
• Information about the presence and stage of complications should be obtained to reduce their risk.

Chronic Complications - Macrovascular, Microvascular, and Neuropathy

• Chronic complications are divided into three categories:
  1. Macrovascular (large vessel or atherosclerotic) disease
     • Coronary artery disease, myocardial infarction, cerebrovascular accident, peripheral arterial disease
  2. Microvascular (small vessel) disease
     • Diabetic retinopathy (eye disease), diabetic nephropathy (kidney disease)
  3. Neuropathy
     • Peripheral and autonomic nervous systems

Chronic Complications - Macrovascular Disease

• Diabetes is a major risk factor for macrovascular disease affecting the heart, brain, and lower extremities.
• Blockage of blood vessels in the legs results in peripheral artery disease, intermittent claudication, and exercise intolerance.

Chronic Complications - Microvascular Disease

• Microvascular disease causes retinopathy and nephropathy, resulting in abnormal function and damage to small vessels of the eyes and kidneys.
• Retinopathy can lead to blindness, and end-stage renal failure is the most serious complication of nephropathy.

Chronic Complications - Peripheral Neuropathy

• Typically affects the legs before the hands.
• Patients may experience sensory symptoms including paraesthesia, burning sensations, and hyperaesthesia, as well as a loss of tendon reflexes.
• As the complication progresses, the feet become insensate, putting patients at high risk for foot trauma.
• Muscle weakness and atrophy can also occur.
• Foot deformities can result, causing increased pressure from shoe wear or foot strike, placing them at risk for injury.
• Lower limb amputations result from loss of sensation and diminished circulation.
• Instruction on foot examination and care is crucial, especially when someone with peripheral neuropathy begins an exercise program.
• Having peripheral neuropathy may also change gait and balance, increasing the risk for falling, but balance training may help lower this risk.

Chronic Complications - Autonomic Neuropathy

• May occur in any system of the body (cardiovascular, respiratory, neuroendocrine, gastrointestinal).
• Cardiovascular autonomic neuropathy is manifested by high resting heart rate, attenuated exercise heart rate response, abnormal blood pressure, and redistribution of blood flow response during exercise.
• This combination can severely limit exercise capacity and physical functioning.

Time in Range Goals

• Optimal (for most youth and adults): 70% (almost 17 h), Glucose target 70-180 mg - dL-1 (3.9-10.0 mmol - L-¹) .
• Pregnancy: 70% (almost 17 h), Glucose target 63-140 mg - dL-1 (3.5-7.8 mmol L-1).
• Older or sicker adults: 50% (12 h), Glucose target 70-180 mg - dL-1 (3.9-10.0 mmol L-1).
• Hypoglycemia: <4% (1 h),Severe hypoglycemia: <1% for older or sicker. <70 mg - dL-1
  (<3.9 mmol L-1). <54 mg - dL-1
  (<3.0 mmol - L-1)
• Hyperglycemia:

Diagnostic Criteria for Diabetes

• Fasting plasma glucose: Diabetes ≥7.0 mmol - L^{-1} (126 mg - dL^{-1}), Prediabetes ADA and CDC: 5.6-6.9 mmol L^{-1} (100-125 mg dL^{-1}) WHO: 6.1-6.9 mmol L^{-1} (110-125 mg dl^{-1})
• Two-hour plasma glucose: Impaired glucose tolerance (IGT): 7.7-11.0 mmol - L^{-1} (140-199 mg - dL^{-1})
  Diabetes ≥11.1 mmol - L^{-1} (200 mg - dL^{-1})
• A1c: Prediabetes 5.7-6.4\%(39-47 mmol - mol-1), Diabetes ≥6.5\%(48 mmol - mol-1)

Glycemic Recommendations for Non-Pregnant Adults

• A1c: <7.0\%
• Preprandial capillary plasma glucose: 80-130 mg - dL^{-1} (4.4-7.2 mmol - L^{-1})
• Peak postprandial capillary plasma glucose: <180 mg - dL^{-1} (<10.0 mmol - L^{-1})

Signs and Symptoms of Diabetes

• Classic symptoms: polydipsia, polyuria, polyphagia
• Other symptoms: unexplained weight loss, slow-healing infections/cuts, blurry vision, fatigue
• Many with type I diabetes have some or all of these symptoms, but those with type II diabetes may remain asymptomatic
• About one-fourth of those with diabetes do not know they have the disease

History and Physical Examination for Diabetic Patients

• Annual physical examination should evaluate for potential indicators of complications:
  • Elevated resting heart rate
  • Loss of sensation/reflexes (especially in lower extremities)
  • Foot sores/ulcers that heal poorly
  • Excessive bruising
  • Retinal vascular abnormalities
• Exercise testing may be appropriate before beginning an exercise program

Considerations Before Exercise

• When determining whether a medical clearance for exercise is needed, consider:
  • Exercise participation and training status
  • Body weight and BMI
  • Resting blood pressure
  • Laboratory values for HbA1c, plasma glucose, lipids, and proteinuria
  • Presence/absence of acute and chronic complications
  • Severity of chronic complications (if present)
  • Other non-diabetes-related health issues
• Prior to each exercise training session, inquire about:
  • Starting blood glucose level
  • Timing, amount, and type of recent food intake
  • Medication use and timing

Exercise Testing

• For low-intensity exercise, health care professionals should use clinical judgement in deciding whether to recommend pre-exercise testing.
• Exercise testing before starting participation in most low- to moderate-intensity activities (<60\% of HRR) is considered unnecessary.
• Indications for ECG stress testing:
  1. Age > 40 years, with or without CVD risk factors other than diabetes
  2. Age > 30 years and any of the following:
     • Type I or type II diabetes of > 10 years
     • Hypertension
     • Cigarette smoking
     • Dyslipidaemia
     • Proliferative or preproliferative retinopathy
     • Nephropathy including microalbuminuria
  3. Any of the following, regardless of age:
     • Known or suspected coronary artery disease, cerebrovascular disease, or peripheral artery disease
     • Autonomic neuropathy
     • Advanced nephropathy with renal failure
• Coronary ischaemia is less likely to occur during resistance compared with aerobic training at the same heart rate response.

Treatment of Diabetes

• There is currently no cure for diabetes; must be managed with exercise, medical nutrition therapy, self-monitoring of blood glucose, diabetes self-management education, and medication (always needed in type I diabetes) or significant weight loss from bariatric surgery or a complete meal replacement diet.
• Few diseases require the same level of ongoing daily patient involvement as does diabetes.

Monitoring of Blood Glucose

• Self-monitoring of blood glucose is an important part of managing diabetes.
• No standard frequency for self-monitoring has been established, but it should be performed frequently enough to help the patient meet treatment goals.
• Increased frequency of testing is often required when people begin an exercise program to assess blood glucose before and after exercise and to allow safe exercise participation.

Continuous Glucose Monitoring

• Individuals with both type 1 and type 2 diabetes may be able to use continuous or flash glucose monitoring devices to get more frequent feedback about their glycaemic levels and responses.
• Such systems allow users to see dynamic data for glucose values, trends, rate of change, and time in range and can alert them to glucose levels that are too low or too high.

Blood Glucose Monitoring and Exercise

• When people with diabetes begin an exercise program, it is helpful to closely monitor their glycaemic levels.
• Monitoring and recording their levels before and after exercise (regardless of the method) may do the following:
  • Allow for early detection and prevention of hypoglycaemia or hyperglycaemia
  • Help determine appropriate pre-exercise BGL to lower the risk of hypoglycaemia or hyperglycaemia
  • Identify those who can benefit from monitoring during and after exercise
  • Provide information for modifying the exercise prescription
  • Allow for better adjustment of diabetes regimens to manage all activities
  • Motivate patients to remain more active to better manage their diabetes

Exercise Testing Summary

• Cardiovascular:
  • Mode: Treadmill, Ergometer (leg or arm)
  • Protocol specifics: Low level for many (<2 METs per stage or 20 W/min increases in work rate)
  • Clinical measures: Peak V.O_2 or estimated METS, Heart rate and blood pressure responses, 12-lead ECG
  • Clinical implications: Watch for ischemia and arrhythmias because these are often undiagnosed and patients are at high risk for heart disease.
  • Special considerations: Chest pain due to myocardial ischemia may not be perceived in those with neuropathy; Patients with peripheral vascular disease or peripheral neuropathy may need to be assessed using the cycle ergometer mode; Consider testing blood glucose before exercise test to reduce the risk of hypoglycemia or hyperglycemia.
• Resistance:
  • Mode: Machine weights
  • Test type: 1RM or indirect 1RM method Strength and power
  • Clinical implications: Perform to allow for safe initiation of resistance training and to compare for change after implementing a training routine.
  • Special considerations: 1RM may not be recommended in those with severe disease and those who are sedentary; Those with severe or unstable proliferative retinopathy most typically should not perform heavy resistance training; Patients should not hold their breath at any time; any exercise may result in excessive blood pressure response.
• Range of motion:
  • Mode: Sit-and-reach test, Goniometry
  • Protocol specifics: Range of motion in major muscle groups
  • Clinical implications: Perform to demonstrate deficiencies and to compare for change after implementing a training routine.
• Blood glucose responses to physical activity are influenced by a large number of factorsBlood glucose responses to physical activity are influenced by a large number of factors, especially in insulin users, who must precisely manage circulating insulin levels before, during, and after exercise.

Exercise Prescription

• Exercise is a vital component of diabetes management and is considered a method of treatment for type II diabetes because it can improve insulin resistance
• Although exercise alone is not considered a method of treating type I diabetes because of the absolute requirement for insulin, it is still an important part of a healthy lifestyle for people in this group
• When frequency and duration are sufficient, exercise performed at an intensity below the threshold for an increase in maximal oxygen uptake can be beneficial to health in persons with a chronic disease like diabetes
• Exercise that can be readily maintained at a constant intensity may be preferred for patients with complications who require more precise control of intensity, whereas higher-intensity intervals may lead to greater gains in overall fitness in those who are able to undertake such training

Macrovascular Disease and Diabetes

The primary macrovascular diseases are coronary artery disease and peripheral artery disease

Peripheral Neuropathy and Exercise

• The major consideration in patients with peripheral neuropathy is the loss of protective sensation in the feet and legs that can lead to musculoskeletal injury and infection
• Those without acute foot wounds or injuries can undertake moderate weight-bearing exercise, but anyone with a foot injury, open sore or foot ulcer should be restricted to non-weight bearing activities (i.e. chair exercises or upper limb exercises)
• Proper footwear and examination of the feet are especially important for these patients

Autonomic Neuropathy and Exercise

• Cardiovascular autonomic neuropathy is manifested by abnormal heart rate, abnormal blood pressure and redistribution of blood flow
• Patients with cardiovascular autonomic neuropathy have a higher resting heart rate and lower maximal exercise heart rate than those without the condition. Thus, estimating peak heart rate in this population may lead to an overestimation of the training heart rate range if heart rate-based methods are used
• Exercise intensity may be accurately prescribed using the heart rate reserve method, with maximal heart rate directly measured, but rating of perceived exertion can also be used to guide intensity
• The risk of exercise hypotension and sudden death increases with cardiovascular autonomic neuropathy. An active cool-down reduces the possibility of a post-exercise hypotensive response
• Moderate-intensity aerobic training can improve autonomic function in those with and without cardiovascular autonomic neuropathy
• Patients with cardiovascular autonomic neuropathy should have an exercise stress test and Physician approval before starting an exercise program
• Because of difficulty with thermoregulation, they should be advised to stay hydrated and not to exercise in hot or cold environments

Retinopathy and Exercise

• Those with proliferative or severe non-proliferative diabetic retinopathy should be carefully screened before beginning an exercise program
• Activities that increase intraocular pressure such as high-intensity aerobic and resistance training with large increases in SBP, head-down activities and jumping/jarring activities are not advised with severe non-proliferative or proliferative retinopathy
• People should never exercise during an active retinal haemorrhage

Nephropathy and Exercise

• Elevated blood pressure is related to the onset and progression of diabetic nephropathy
• Placing limits on low- to moderate-intensity activity is not necessary, but strenuous exercises should likely be discouraged in those with diabetic nephropathy because of the elevation in blood pressure and general fatigue

Exercise Recommendations

• Patients who are trying to lose weight, especially those with type II diabetes, should expend a minimum of 2,000 kcal per week in aerobic activity and participate in a well-rounded resistance training program
• Patient interests, goals of therapy, type of diabetes, medication use (if applicable) and presence and severity of complications must be carefully evaluated in developing the exercise prescription

Cardiopulmonary Exercise

• Given the high risk for developing atherosclerotic disease in those with diabetes, the ameliorating effects of cardiorespiratory exercise may help reduce this risk

Mode

• Walking is the most commonly performed mode of activity in adults with T2DM as it is a convenient, low-impact activity that can be used safely and effectively to maximise caloric expenditure
• Non-weight-bearing modes should be used if necessary, such as when sores are noted on the feet
• For a given level of energy expenditure, the health-related benefits of cardiopulmonary exercise appear to be independent of the mode

Intensity

• Programs of moderate intensity are preferable for most people with diabetes because the cardiovascular risk and chance for musculoskeletal injury are lower and the likelihood of maintaining the exercise program is greater
• With attention to safety, it may be beneficial for those already exercising at a moderate intensity to consider some vigorous physical activity or at least inclusion of some faster intervals interspersed into less intense training
• Exercise should generally be prescribed at an intensity of 40 – 59% of HRR, or at an RPE of 11 – 13, to be considered moderate
• Vigorous exercise is 60 – 85% of HRR, or at an RPE of 14 – 16 for most individuals

Frequency

• The frequency of exercise should be 3 – 7 days per week
• The blood glucose improvements in those with diabetes last only 2 – 72 hours, suggesting that activity should be done minimally on three non-consecutive days each week with no more than two consecutive days between bouts
• Those who take insulin and have difficulty balancing caloric needs with insulin dosage may prefer to exercise daily for consistency. This schedule may result in less daily adjustment of insulin dosage and caloric intake than a schedule in which exercise is performed every other day or sporadically, and it will reduce the likelihood of a hypoglycaemic or hyperglycaemic response

Duration and Progression

• Exercise duration for those with diabetes should be 150 - 300 minutes per week or more of moderate activity (ideally spread throughout the week, such as 30 minutes, 5 days/week) or 75 - 150 minutes of vigorous activity
• Bouts of exercise should ideally be a minimum of 10 minutes, but unfit individuals can start with shorter bouts and benefit from doing so
• Gradual progression of both intensity and volume is recommended to reduce the risk of injury

Timing

• Because of the risk of hypoglycaemia, those taking insulin should give careful consideration to the time of day they perform exercise and should avoid activity when insulin is peaking
• Muscle contractions promote peripheral glucose uptake via a contraction-induced mechanism involving calcium release and translocation of GLUT 4 glucose transport proteins
• Given that insulin itself can bind to a cellular receptor and promote the uptake of glucose from blood into muscles (both at rest and during exercise), and this insulin-associated uptake involves a separate pool of GLUT 4 proteins, the risk of hypoglycaemia greatly increases during activity
• The independent effects of exercise and insulin on blood glucose levels are known to be additive

Glycogen Replacement

• The replacement of muscle glycogen after exercise also increases the risk of hypoglycaemia. This happens because blood glucose is utilised within muscle cells to restore glycogen after exercise, and uptake of blood glucose requires very little insulin in the first couple of hours following the activity
• Exercising late in the evening for those on insulin and some oral medications may be more difficult to manage because of the possible occurrence of hypoglycaemia during sleep

Rapid Acting Insulin

• Do not allow patients to exercise at the peak insulin dose of a rapid acting insulin (first 2 hours following drug administration)

Resistance Exercise and Diabetes

• Resistance training programs can improve cardiovascular function, insulin sensitivity, strength and body composition in people with diabetes
• Additionally, people with T1DM may experience more stable BGLs during resistance training when compared with aerobic activities
• A recommended resistance training program consists of 5 – 10 exercises involving major muscle groups performed with 1 – 3 sets of 8 – 15 repetitions to near fatigue
• Resistance training exercises should be done 2 – 3 days per week on non-consecutive days
• Progression of intensity, frequency and duration should occur slowly: increases in resistance should be made first and only once the target number of repetitions per set can be exceeded, followed by a greater number of sets and then increased training frequency
• Modifications such as lowering the intensity of lifting and minimising the amount of sustained gripping or isometric contractions should be considered to ensure safety given that people with diabetes are more prone to overuse and other tendon, ligament and joint injuries

Range of Motion and Balance Exercise

• ROM exercises can be included as part of an exercise program, but should not be substituted for aerobic or resistance exercise
• It is recommended that all individuals over the age of 40 engage regularly in balance training, which is known to reduce the risk of falls in people with diabetes and even with peripheral neuropathy

Exercise Prescription Review

Exercise Training Considerations

• Exercise training promotes blood glucose uptake by the skeletal muscles. People who use insulin or selected oral glucose-lowering medications may run the risk of hypoglycaemia
• The heart rate response of those with longstanding diabetes may be impaired. They may have a higher than typical resting heart rate and a lower peak heart rate on an exercise test
• Do not exercise a patient who reports a BGL > 13.9 mmol/L if moderate or higher levels of ketones are present. If it is deemed safe to exercise a patient with a BGL > 16.5 mmol/L without ketones, be sure the patient is hydrated and feels well

Prevention and Treatment of Abnormal Blood Glucose - Pre-Exercise Hypoglycaemia

• Blood glucose levels should be monitored before an exercise session to determine whether the person can safely begin exercising, especially someone using insulin or selected glucose-lowering oral agents that cause the pancreas to release insulin (such as sulphonylureas)
• If diabetes is managed by diet or oral glucose-lowering medications with little or no risk of hypoglycaemia, most patients will not need to consume supplemental carbohydrate for exercise lasting less than 60 minutes
• If blood glucose is less than 5.5 mmol/L and the exercise will be of low intensity and short duration (eg. bike riding or walking for less than 30 minutes), 5 – 10 grams of carbohydrate should be consumed. If blood glucose is greater than 5.5 mmol/L, no extra carbohydrate is likely needed
• If blood glucose is less than 5.5 mmol/L and exercise is of moderate intensity and moderate duration (e.g. jogging for 30 – 60 minutes), 25 – 45 grams of carbohydrate should be consumed. If blood glucose is 5.5 – 10 mmol/L, then 15 – 30 grams of carbohydrate is needed
• If blood glucose is less than 5.5 mmol/L and exercise is of moderate or vigorous intensity and long duration (eg. more than 60 minutes of cycling), then 45 grams of carbohydrate should be consumed. If blood glucose is 5.5 – 10 mmol/L, 30 – 45 grams of carbohydrate is needed
• Remember that these guidelines will need to be used on a trial-and-error basis and individualised for each patient. In addition, someone trying to lose weight might benefit from a medication adjustment rather than increased food intake

Carbohydrate Intake Guidelines for Exercise