Week 5 Lecture Slides (Part 1 & Part 2) PDF

EHR522 EXERCISE FOR METABOLIC & RENAL CONDITIONS WEEK 5 – DIABETES (TYPE I, TYPE II & GESTATIONAL) DIABETES • Exercise has long been recognised as an important component of diabetes care and now is considered an important component in the prevention or delay of type II diabetes • Despite this, onl...

EHR522 EXERCISE FOR METABOLIC & RENAL CONDITIONS WEEK 5 – DIABETES (TYPE I, TYPE II & GESTATIONAL) DIABETES • Exercise has long been recognised as an important component of diabetes care and now is considered an important component in the prevention or delay of type II diabetes • Despite this, only 39% of adults with diabetes are physically active (defined as engaging in moderate or vigorous activity for at least 30 minutes, three times per week) compared to 58% of other adults 2 DIABETES • Diabetes Mellitus – A group of metabolic diseases characterised by an inability to produce sufficient insulin or use it properly, resulting in hyperglycaemia, or elevations in blood glucose • Insulin, a hormone produced by the pancreas is needed by the skeletal muscles, adipose tissue, and the liver to take up and use glucose, which is essential for proper functioning of the brain and nerves • The elevations in blood glucose associated with uncontrolled diabetes increase the risk for acute and chronic health issues, including cardiovascular (macrovascular) disease, microvascular diseases like retinopathy and nephropathy, and nerve damage (both autonomic and peripheral neuropathy) 3 DIABETES - SCOPE • Asymptomatic individuals with diabetes and pre-diabetes are at increased risk for developing long-term health complications • Diabetes is currently the 7th leading cause of death in the United States • Death rates of people with diabetes are twice those of people without diabetes of the same age • The economic effect of diabetes is staggering, and a large portion of the economic burden of diabetes is attributable to long-term complications and hospitalisations 4 PATHOPHYSIOLOGY • While classification assists in determining the best treatment options, diabetes cannot always be clearly classified by type at the time of diagnosis 5 PATHOPHYSIOLOGY – TYPE I DIABETES • Type I diabetes comprises two subgroups: • Immune-mediated • Idiopathic • Type I immune-mediated diabetes was formerly known as juvenile-onset or insulin-dependent diabetes and accounts for approximately 5 – 10% of those with diabetes. • This form of diabetes is considered an autoimmune disease in which the immune system attacks the body’s own beta cells, resulting in absolute deficiency of insulin. Consequently, insulin must be supplied by regular injections or an insulin pump 6 PATHOPHYSIOLOGY – TYPE I DIABETES • Type I immune-mediated diabetes more frequently occurs in childhood and adolescence, but can occur at any age • Type I idiopathic diabetes has no known aetiologies and is present in only a small number of people, most of African or Asian ancestry. This form of type I diabetes is strongly inherited and lacks evidence of beta cell autoimmunity 7 PATHOPHYSIOLOGY – TYPE II DIABETES • Type II diabetes was formerly called adult-onset or non- insulin-dependent diabetes. This is the most common form of the disease and affects approximately 90% to 95% of all those with diabetes • The onset of type II diabetes usually occurs after age 40, although it is seen at increasing frequency in adolescents • The pathophysiology of type II diabetes is complex and multifactorial. Insulin resistance of the peripheral tissues and defective insulin secretion are common features 8 PATHOPHYSIOLOGY – TYPE II DIABETES • The treatment options are lifestyle management, including medical nutrition therapy (MNT) and physical activity, and if medication is needed to reach glycaemic targets, oral agents, insulin or other injectable diabetes medications • Bariatric surgery may also be added to the treatment plan for those who are obese (BMI > 35), especially if the diabetes or comorbidities are unmanageable with lifestyle and medication • Ketoacidosis rarely occurs in type II diabetes 9 PATHOPHYSIOLOGY – TYPE II DIABETES • A genetic influence is present for type II diabetes. The risk for type II diabetes among offspring with a single parent with type II diabetes is 3.5-fold higher, and the risk for those with two such parents is 6-fold higher compared with offspring of people who don’t have the disease • In addition, obesity contributes significantly to insulin resistance, and most people (80%) with type II diabetes are overweight or obese at disease onset • The risk of developing type II diabetes also increase with age, lack of physical activity, history of gestational diabetes and presence of hypertension or dyslipidaemia 10 PATHOPHYSIOLOGY – GESTATIONAL DIABETES • Since many women who become pregnant may have prior undiagnosed diabetes, gestational diabetes is defined as “diabetes diagnosed in the second or third trimester of pregnancy that is not clearly either type I or type II diabetes.” • It is usually diagnose with OGTT, performed routinely at 24 – 28 weeks of pregnancy • Risk factors for developing gestational diabetes include • Family history of gestational diabetes • Previous delivery of large birth weight (> 9lb / 4kg) • Obesity 11 PATHOPHYSIOLOGY – GESTATIONAL DIABETES • Although glucose usually returns to normal after delivery, women who have had gestational diabetes have a greatly increased risk of conversion to type II diabetes over time • They are recommended to have lifelong screening for the development of diabetes or pre-diabetes at least every three years • Structured moderate physical exercise training during pregnancy decreases the risk of gestational diabetes, diminishes maternal weight gain and is safe for the mother and neonate 12 OTHER SPECIFIC TYPES OF DIABETES • In other specific types of diabetes, certain diseases, injuries, infections, medications or genetic syndromes cause the diabetes. This type may or may not require insulin treatment 13 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • The acute complications of diabetes are - Hyperglycaemia (high blood glucose) - Hypoglycaemia (low blood glucose) • Each of these acute complications must be quickly identified to ensure proper treatment and reduce the risk of serious consequences • The manifestations of hyperglycaemia are as follows - Diabetes out of control - Diabetic ketoacidosis - Hyperosmolar non-ketotic syndrome 14 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • High blood glucose levels cause the kidneys to excrete glucose and water, which causes increased urine production and dehydration • Symptoms of high blood glucose levels and dehydration include - Headache - Weakness - Fatigue • The best treatment for anyone with diabetes out of control includes drinking plenty of non-carbohydrate-containing beverages, regular self-monitoring of blood glucose, and, when instructed by a health care professional, an increase in diabetes medications • Frequent high blood glucose levels damage target organs or tissues over time, which increases the risk of chronic complications 15 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Diabetic ketoacidosis occurs in patients whose diabetes is in poor control and in whom the amount of effective insulin is very low or absent. This result is much more likely to occur in those with type I diabetes • Ketones form because without insulin, the body cannot use glucose effectively, and ineffective fat metabolism occurs to provide necessary energy • A by-product of fat metabolism in the absence of adequate carbohydrate is ketone body formation by the liver, causing an increased risk of coma and death 16 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • 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. • This level of ketosis can be evaluated with a urine dipstick test or a fingerstick blood test • Other 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 17 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Hyperglycaemic hyperosomolar non-ketotic syndrome occurs in patients with type II diabetes when hyperglycaemia is profound and prolonged • This circumstance is most likely to happen during periods of illness or stress, in the elderly, or in people who are undiagnosed • This syndrome results in severe dehydration attributable to rising blood glucose levels, causing excessive urination. Extreme dehydration eventually leads to decreased mentation and possible coma • Exercise is also contraindicated in anyone experiencing hyperglycaemic hyperosmolar non-ketosis 18 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Hypoglycaemia is a potential side effect of diabetes treatment and usually occurs when blood glucose levels drop below 60 – 70 mg/dL (3.3 – 3.9 mmol/L) • Hypoglycaemia may occur in the presence of the following factors: - Too much insulin or selected anti-diabetic oral agent/s - Too little carbohydrate intake - Missed meals - Excessive or poorly planned exercise 19 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Hypoglycaemia can occur either during exercise or hours to days later • Late-onset post-exercise hypoglycaemia generally occurs following moderate- to high-intensity exercise that lasts longer than 30 minutes. • This kind of hypoglycaemia results from - Increased insulin sensitivity - On-going glucose use - Physiological replacement of glycogen stores through gluconeogenesis 20 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Patients should be instructed to monitor blood glucose levels before and periodically after exercise to assess glucose response. This approach is also recommended in clinical exercise programs, such as cardiac rehabilitation, especially in patients new to exercise • The two categories of symptoms of hypoglycaemia are adrenergic and neuroglycopaenic 21 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • As blood glucose decreases, glucose-raising hormones (ie. glucagon, epinephrine, growth hormone and cortisol) are released to help increase circulating blood glucose levels • Adrenergic symptoms such as shakiness, weakness, sweating, nervousness, anxiety, tingling of the mouth and fingers, and hunger result from epinephrine release • As blood glucose delivery to the brain decreases, neuroglycopaenic symptoms like headache, visual disturbances, mental dullness, confusion, amnesia, seizures or coma may occur 22 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Hypoglycaemia Unawareness – The inability to sense hypoglycaemic symptoms • Instituting tight control of blood glucose may lower the threshold so that symptoms do not occur until blood glucose drops quite low. Intensity of control may need to be slightly reduced to alleviate hypoglycaemia unawareness • In contrast, patients who have been in poor control may have symptoms associated with low blood glucose levels much higher than 3.9 mmol/L 23 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • Treatment of hypoglycaemia consists of testing blood glucose to confirm hypoglycaemia and consumption of approximately 15 grams of carbohydrate (eg. glucose, sucrose or lactose) that contains minimal or no fat • 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 24 COMPLICATIONS OF DIABETES – ACUTE COMPLICATIONS • The person with diabetes should 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 hypoglycaemia, an ambulance should be called and glucagon should be administered 25 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • Diabetes is the leading cause of adult-onset blindness, non-traumatic lower limb amputation and end-stage renal failure • In addition, those with diabetes are at two to four times the normal risk of heart disease and stroke • Chronic exposure to hyperglycaemia is considered of primary importance in development of the chronic complications, along with hypertension and hyperlipidaemia • Intensive blood glucose control can reduce the risk of developing microvascular diabetic complications in anyone with type I or type II diabetes • In diabetic patients you should obtain information about the presence and stage of complications, with the objective of reducing their risk of developing and/or amplifying these complications 26 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • In determining appropriate exercise programming for people with diabetes, it is helpful to divide the chronic complications into three categories 1. Macrovascular (large vessel or atherosclerotic) disease, which includes coronary artery disease with or without angina, myocardial infarction, cerebrovascular accident and peripheral arterial disease 2. Microvascular (small vessel) disease, which includes diabetic retinopathy (eye disease) and diabetic nephropathy (kidney disease). 3. Neuropathy that involves both the peripheral and autonomic nervous systems 27 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • Diabetes is a major risk factor for macrovascular disease. The vessels to the heart, brain and lower extremities can be affected. • Blockage of the blood vessels in the legs results in peripheral artery disease, intermittent claudication and exercise intolerance • Reduction and control of vascular risk factors are especially important in those with diabetes. The methods used for this purpose are similar to those used for coronary heart disease 28 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • Microvascular disease causes retinopathy and nephropathy, which result in abnormal function and damage to the small vessels of the eyes and kidneys, respectively • The ultimate result of retinopathy can be blindness, whereas end-stage renal failure is the most serious complication of nephropathy • Prevention or appropriate management requires periodic dilated eye examinations and renal function tests, along with optimal blood glucose and blood pressure control 29 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • Peripheral neuropathy typically affects the legs before the hands. • Patients may initially 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 that can go undetected • Muscle weakness and atrophy can also occur • Foot deformities can result, causing areas to receive increased pressure from shoe wear or foot strike, placing them at risk for injury 30 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • The large number of lower limb amputations from diabetes results from loss of sensation that places the patient at risk for injury and from diminished circulation attributable to peripheral artery disease • This circumstance impairs healing and can lead to severe reductions in blood flow, potential gangrene and amputation • Persons with diabetes must be given instruction on how to examine their feet and practice good foot care. Foot care is especially important when someone with peripheral neuropathy begins an exercise program because increased walking and cycle pedalling increases the risk of foot injury • Having peripheral neuropathy may also change gait and ability to balance, increasing the risk for falling, but balance training may help lower this risk 31 COMPLICATIONS OF DIABETES – CHRONIC COMPLICATIONS • Diabetic autonomic neuropathy may occur in any system of the body (eg. cardiovascular, respiratory, neuroendocrine, gastrointestinal). Many of these systems are integral to the ability to perform exercise • 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 32 DIAGNOSTIC CRITERIA 33 GLYCAEMIC RECOMMENDATIONS FOR NON-PREGNANT ADULTS WITH DIABETES 34 SIGNS AND SYMPTOMS • • • The classic symptoms of diabetes include - Polydipsia (excessive thirst) - Polyuria (frequent urination) - Polyphagia (excessive hunger) Other symptoms of diabetes include - Unexplained weight loss - Infections and cuts that are slow to heal - Blurry vision - Fatigue Many who develop 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 35 PART 2 36 36 HISTORY AND PHYSICAL EXAMINATION • Patients with diabetes having an annual physical examination should be evaluated for potential indicators of complications. These may include - Elevated resting heart rate - Loss of sensation or reflexes, especially in the lower extremities - Foot sores or ulcers that heal poorly - Excessive bruising - Retinal vascular abnormalities • Exercise testing may be appropriate before beginning an exercise program 37 HISTORY AND PHYSICAL EXAMINATION • In making a determination regarding the necessity of obtaining a medical clearance for exercise, you should consider − Exercise participation and training status − Body weight and BMI − Resting blood pressure − Laboratory values for HbA1c, plasma glucose, lipids and proteinuria − Presence of absence of acute and chronic complications − If chronic complications exist, the severity of those complications − Other non-diabetes-related health issues 38 HISTORY AND PHYSICAL EXAMINATION • Of more immediate concern, prior to each exercise training session, you may inquire about the following to help the patient prevent acute complications like hypoglycaemia or hyperglycaemia - Starting blood glucose level (self-monitored or measured by you) - Timing, amount and type of most recent food intake - Medication use and timing 39 HISTORY AND PHYSICAL EXAMINATION • For participation in low-intensity exercise, health care professionals should use clinical judgement in deciding whether to recommend pre-exercise testing • Conducting exercise testing before starting participation in most low- to moderate-intensity activities is considered unnecessary 40 HISTORY AND PHYSICAL EXAMINATION • In general, ECG stress testing may be indicated for individuals meeting one or more of these criteria 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 41 HISTORY AND PHYSICAL EXAMINATION • There is no evidence to determine if stress testing is necessary or useful before participation in anaerobic or resistance training • Coronary ischaemia is less likely to occur during resistance compared with aerobic training at the same heart rate response 42 TREATMENT • There is currently no cure for diabetes. The disease must be managed with a program of exercise, medical nutrition therapy, self-monitoring of blood glucose, diabetes self-management education and, when needed, 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. Since so much patient involvement is required, patients must receive information and training on disease management 43 TREATMENT • Self-monitoring of blood glucose is also 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 • Patients must be given guidance about how to use the information to make exercise, food and medication adjustments 44 TREATMENT • Those who require glucose-lowering medication must understand how their medications work with food and exercise to ensure the greatest success and safety • It is important that you understand diabetes medications so you can safely prescribe exercise and provide guidance on exercise training to patients with diabetes 45 EXERCISE TESTING SUMMARY 46 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 47 EXERCISE PRESCRIPTION • 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 48 MACROVASCULAR DISEASE • The primary macrovascular diseases are coronary artery disease and peripheral artery disease 49 PERIPHERAL NEUROPATHY • 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 50 AUTONOMIC NEUROPATHY • 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 51 AUTONOMIC NEUROPATHY • 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 52 RETINOPATHY • 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 53 NEPHROPATHY • 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 54 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 55 CARDIOPULMONARY EXERCISE • The value of cardiopulmonary exercise for persons with diabetes is strong • Given the high risk for developing atherosclerotic disease in those with diabetes, the ameliorating effects of cardiorespiratory exercise may help reduce this risk 56 CARDIOPULMONARY EXERCISE - MODE • Non-weight-bearing modes should be used if necessary • For a given level of energy expenditure, the healthrelated benefits of cardiopulmonary exercise appear to be independent of the mode 57 CARDIOPULMONARY EXERCISE - 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 58 CARDIOPULMONARY EXERCISE - 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 nonconsecutive 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 59 CARDIOPULMONARY EXERCISE – DURATION AND RATE OF PROGRESSION • Exercise duration for those with diabetes should be a minimum of 150 minutes per week of moderate activity (30 minutes, 5 days/week) or 60 to 75 minutes of vigorous activity (20 minutes, 3 days/week) • 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 60 CARDIOPULMONARY EXERCISE – 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, and the combination of exercise and higher circulating insulin levels increases the risk of hypoglycaemia • 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 61 RESISTANCE EXERCISE • Resistance training programs can improve cardiovascular function, glucose tolerance, strength and body composition in people with diabetes • 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 62 RANGE OF MOTION EXERCISE • ROM exercises can be included as part of an exercise program, but should not be substituted for aerobic or resistance exercise 63 EXERCISE PRESCRIPTION SUMMARY 64 EXERCISE TRAINING • Exercise training considerations for diabetes include the following − 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 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 65 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 glucoselowering oral agents • 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 66 PREVENTION AND TREATMENT OF ABNORMAL BLOOD GLUCOSE – PRE-EXERCISE HYPOGLYCAEMIA • 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 67 PREVENTION AND TREATMENT OF ABNORMAL BLOOD GLUCOSE – PRE-EXERCISE HYPERGLYCAEMIA • If the pre-exercise blood glucose is greater than 16.5 mmol/L, urine or blood can be checked for ketones. If ketones are present (moderate to high), exercise should be postponed until glucose control is improved. If a patient with a blood glucose level greater than 16.5 mmol/L without ketones is safe to exercise, be sure the patient is hydrated 68 PREVENTION AND TREATMENT OF ABNORMAL BLOOD GLUCOSE – PRE-EXERCISE HYPERGLYCAEMIA • Patients who use medication as part of diabetes treatment should be assessed to determine whether the timing and dosage of medication will allow exercise to have a positive effect on blood glucose. • For example, a patient who uses insulin and had a blood glucose level of 15 mmol/L, had no ketones and took regular insulin within 30 minutes will see a reduction in blood glucose from both the insulin and exercise. • If this patient has not just administered fast-acting insulin and the previous insulin injection has run its duration, the patient has too little circulating insulin – more will be needed to help reduce the blood glucose level before exercise. In this case, most physical activity would likely increase the blood glucose level 69 PREVENTION AND TREATMENT OF ABNORMAL BLOOD GLUCOSE – PRE-EXERCISE HYPERGLYCAEMIA • Those with type II diabetes who are appropriately managed by diet and exercise alone usually experience a reduction in blood glucose level with low to moderate exercise • Timing of exercise after meals can help many patients with type II diabetes reduce post-prandial hyperglycaemia • Blood glucose should be monitored after an exercise session to determine the patient’s response to exercise 70 PREVENTION AND TREATMENT OF ABNORMAL BLOOD GLUCOSE – POST-EXERCISE HYPOGLYCAEMIA • Patients are more likely to experience hypoglycaemia (usually < 3.9 mmol/L) after exercise than during due to post-exercise replacement of muscle glycogen, which uses blood glucose • Periodic monitoring of blood glucose is necessary in the hours following exercise to determine whether blood glucose is dropping • More frequent monitoring is especially important when initiating exercise 71 PREVENTION AND TREATMENT OF ABNORMAL BLOOD GLUCOSE – POST-EXERCISE HYPERGLYCAEMIA • In poorly controlled diabetes, insulin levels are often too low, resulting in an increase in counter-regulatory hormones with exercise. This circumstance causes glucose production by the liver, enhanced free fatty acid release by adipose tissue and reduced muscle glucose uptake • The result, more likely in type I diabetes than type II diabetes, can be an increased blood glucose level during and after exercise • High-intensity exercise can also result in hyperglycaemia. In this case, the intensity and duration of exercise should be reduced as needed 72 CARDIORESPIRATORY AND RESISTANCE EXERCISE • Benefits for persons with diabetes are seen with both acute and chronic cardiorespiratory and endurance exercise training • Acute bouts of exercise can improve blood glucose, particularly in those with type II diabetes • The response of blood glucose to exercise is related to preexercise blood glucose levels as well as to the duration and intensity of exercise. Many studies on type II diabetes have demonstrated a reduction in BGLs that is sustained into the post-exercise period following mild to moderate exercise, with the reduction attributed to an attenuation of hepatic glucose production along with a normal increase of muscle glucose use 73 CARDIORESPIRATORY AND RESISTANCE EXERCISE • The effect of acute exercise on blood glucose levels in those with type I diabetes and in lean patients with type II diabetes is more variable and unpredictable, but glycaemic benefits are still possible with concomitant dietary management • A rise in blood glucose with exercise can be seen in patients who are extremely insulin deficient (usually type I) and with short-term, high-intensity exercise 74 CARDIORESPIRATORY AND RESISTANCE EXERCISE • Most of the benefits of exercise for those with diabetes of any type come from regular, long-term exercise. These benefits can include improvements in − Metabolic control (glucose control and insulin resistance) − Hypertension − Lipids − Body composition and weight loss or maintenance − Psychological well-being • Both the frequency of aerobic training and the volume of resistance training appear to be important in lowering overall blood glucose levels in type II diabetes 75 CARDIORESPIRATORY AND RESISTANCE EXERCISE • Like acute exercise, exercise training can improve blood glucose. Exercise training (both aerobic and resistance) improves glucose control as measured by HbA1c or glucose tolerance, primarily in those with type II diabetes • Following exercise training, insulin-mediated glucose disposal is improved. Insulin sensitivity of both skeletal muscle and adipose tissue can improve with or without a change in body composition • Exercise may improve insulin sensitivity through several mechanisms, including changes in body composition, muscle mass, fat oxidation, capillary density and glucose transporters in muscle (GLUT4) 76 CARDIORESPIRATORY AND RESISTANCE EXERCISE • Weight loss is often a therapeutic goal for those with type II diabetes because most are overweight or obese. Moderate weight loss improves glucose control and decreases insulin resistance • Visceral or abdominal body fat is negatively associated with insulin sensitivity in that increased abdominal body fat decreases peripheral insulin sensitivity. This body fat is a significant source of free fatty acids and may be preferentially oxidised over glucose, contributing to hyperglycaemia. Exercise results in preferential mobilisation of visceral body fat, likely contributing to the metabolic improvements • Epidemiological evidence supports the role of exercise in the prevention or delay of type II diabetes 77 EXERCISE TRAINING SUMMARY 78 PSYCHOLOGICAL BENEFITS • Psychological benefits of regular exercise have been demonstrated in those without and with diabetes, including reduced stress, reduction in depression and improved self-esteem 79 AMPUTATION • Diabetes is the leading cause of non-traumatic lower limb amputations • Amputations occur because of impaired sensation and circulation in the extremity, resulting in wounds that are not able to heal properly • Walking capacity and performance decrease with progression of foot complications, and the energy cost of walking increases markedly for someone with an amputation and a prosthetic limb • In addition, prolonged walking may cause trauma and ulceration of the stump • Various upper body exercises, including chair exercises, weights and arm ergometry, or non-weight-bearing exercise as swimming (though be weary of any sores or ulcerations), may be better choices 80 WEEKLY READING Ehrman, K. J. (2022). Clinical Exercise Physiology (5th ed.). Chapter 8: Diabetes. Human Kinetics Publishers. 81 81