Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008 pp:1-15

Review Article

Exercise Prescription in Patients with Diabetes Type 2

Esteghamati A1, Hassabi M*∗2, Halabchi F2, Bagheri M 3

1-Endocrine Research Center, university of Tehran/medical sciences, Tehran, Iran

2-Sports Medicine Research Center, university of Tehran/medical sciences, Tehran, Iran

3-Academic Faculty of Department of Internal Medicine, East Tennessee State University, USA

Abstract Sedentary life style is considered as a main risk factor for DM-II. The role of regular exercise is appreciated in both primary prevention and treatment. Diabetic people can benefit from physical activity in order to have a better control on blood glucose level, lipid profile, body weight, and blood pressure. Furthermore, psychological improvements may follow such as decreasing anxiety or depression and improvement of sleep quality. Different kinds of training including aerobic, resistive, and flexibility exercises could be recommended, but some parameters like intensity, duration, and frequency of exercises as well as safety measures should be explained to the patient when prescribing an exercise program. A thorough medical evaluation is required before starting an unaccustomed exercise program in order to modify it, as needed. It is recommended that diabetic people participate in moderate aerobic (40-60% Vo2max) and resistive (30-50% 1RM) exercises 3-5 and 2-3 sessions per week, respectively. However, it is a general recommendation, and an expert in exercise therapy should tailor the program with respect to individual conditions.

Key words: exercise, diabetes type 2, training

∗ Corresponding Author: the Opposite Side of Shari'ati Hospital, Jalal-al-Ahmad St. Tehran, Iran, Tel: + 98 21 88630227, Fax: + 98 21 88003539. E-mail: [email protected] 2 Hassabi et al.: Exercise Prescription in…

Background Communicable Diseases of Iran, 2005, As the level of activities has decreased in revealed that 7.7% of adults aged 25-64 today's living, the incidence of many chronic years (about 2 million adults) have diabetes, physical and psychological problems has among whom one-half are undiagnosed and increased. Obesity and insulin resistance, an additional 16.8% (4.4 million of Iranian two component of the metabolic syndrome, adults) have impaired fasting glucose. [4].

are both consequences of this reduced Although, DM-II typically affects the physical activity during daily life. Metabolic population over 30 years of age, but its syndrome, predicts an increased risk of incidence is on the rise among the pediatric developing type II diabetes and also and adolescence population. The increased cardiovascular diseases. Unfortunately, prevalence of obesity in these groups has modern life style, dictates us to spend a big been suggested as an etiology for the portion of lifetime without any significant increased incidence of diabetes [5]. physical activity. Thus, it's extremely important to include appropriate exercise routine in our daily lives. This would be of benefit in improving the society's general BASIC CONCEPTS IN EXERCISE health and also in managing lots of the TRAINING related pathologies. In this regard, one must Given the use of specific terminology avoid incomprehensive recommendations during discussing the exercise routines, we for exercise, as this could confuse the will first briefly review the essential patient and even encourage him to pursuit terminology: activities that may be hazardous to his health. Of course, the clinician prescribing Exercise training: Is a type of physical exercise regimens should either familiarize activity that has been tailored to improve or himself to the basics of exercise therapy or maintain one or more aspects of physical seek expert opinion in this regard. fitness [6]. Given the high incidence of diabetes type An exercise prescription is based on four II, the proven benefit of exercise routines in characteristics including the type of exertion, its management and the fact that many frequency, intensity and duration [7]. practitioners are unfamiliar with these subjects, we are going to review the Type of exertion: Exercise routines are essential practical points in this field. categorized based on different aspects as we

will review here. Epidemiology

-Aerobic exercises: Activities that More than 90% of diabetic population has incorporate use of large groups of muscle the type II disease. The incidence of this with low to moderate intensity and in disease is more in societies with sedentary longer durations. Walking, jogging, life styles and obesity. The expert swimming and bicycling are some examples consensus is that diabetes type II is of aerobic activities. These activities have evolving into a pandemic which will be one major roles in improving one’s of the health related burdens of the 21st cardiovascular fitness. century [1, 2]. In 2001, a study estimated -Anaerobic exercises: These activities are that more than 1.5 million Iranians suffer generally more intensive than the aerobics from DM-II and also suggested that 14.5- and due to gradual accumulation of lactic 22.5% of the population over 30 years of acid in the involved muscles and the age have either insulin resistance or frank subsequent pain and fatigue, are not diabetes [3]. More recently, the results of suitable for long duration practice. Fast the first Survey of Risk Factors of Non- running, swimming, bicycling and, also, Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008, 3 heavy weight lifting are some examples of more precisely, it is advised to first measure anaerobic activities. These exercises are the heart’s chronotropic reserve (Max HR – generally used to increase one’s speed and Resting HR). Then multiply the min by strength. max intended percentage of heart rate in this chronotropic reserve and finally add -Resistive exercises: This term is usually this minimum and maximum rates to the given to activities done against a resistance. resting heart rate to determine the intended The resistance here may be the body weight range of HR with the prescribed or elastic force or external weights. The routine[1,6]. main goal of these activities is to increase The rating of perceived exertion is used as one’s strength and endurance [1]. One must an estimate of the exercise intensity. RPE keep in mind that, with quitting these offers a numeric measure for different routines for a long time, the improvements levels of activity, ranging from minimum to may be lost. Thus adherence to regular maximum exertion. Point scales like the exercise routines is strongly recommended. BORG scale, rate the exercise intensity -Flexibility exercises: These trainings are from minimum (equal to Borg scale of 6) to intended to increase the overall flexibility maximum (Borg scale of 20). Studies have of body and to improve the range of motion shown that RPE correlates well with the of joints. It is important to point out the VO2 Max and HR and this method is correct way of performing, duration, considered as an invaluable tool in exercise number of repetitions and frequency of prescribing [6,7]. stretching movements while prescribing Repetition maximum (RM) is usually used them [1]. to determine the intensity of resistive Frequency: Frequency refers to the number exercises. RM is defined as the maximum of sessions practiced weekly. The weight or load that muscle can bear in a recommended frequency is usually 3 to 5 given range of motion with a given sessions weekly. If adhering to the 3 days a repetition. 1RM applies to the maximum week frequency protocol, one may space weight that muscle can overcome no more practice sessions to every other day, so that than once. Thus, nRM applies to the the overall exertion be distributed more maximum load that muscle can overcome, n evenly throughout the week [6, 7]. times and not more. Usually a percentage of Intensity: One could monitor the intensity the RM is used to determine the amount of of aerobic exercises via different methods. load or resistance used in resistive exertions VO2 Max, Target heart rate and RPE are [1, 7]. some of these measures [6]. Given the costs and the needed The role of physical activity in infrastructure for directly measuring the VO2 diabetics Max, in real world, exercise sessions are prescribed and monitored via easier and Diet, prescription anti hyperglycemic drugs more available methods [1]. and exercise routines are all important Heart rate is directly proportional to the contributors to treatment of diabetes. Physical activity and sports are one of the intensity of exertion and the VO2 Max. Accordingly, often the intensity of exercise main contributors to both prevention and is determined based on the maximal management of diabetes. predicted heart rate (Max HR= 220 - Age). Prevention: Metabolism abnormalities The intensity of exercise should be adjusted leading to insulin resistance are usually as to maintain the HR within a given range reversed by weight loss, dieting and during exertion, for example, 60-80% of increase in physical activity. Exercise may Max HR. In order to measure this range increase body’s response to intrinsic insulin, by multiple mechanisms including 4 Hassabi et al.: Exercise Prescription in… increasing the amount of transporters of fitness and psychological state of health. glucose into the muscle cells (GLUT-4), Exercise in diabetics is beneficial in both increasing of insulin receptor substrates primary and secondary prophylaxis of (IRS) and last but not least, increasing the cardiovascular diseases (Table-1) [5, 12, and muscle mass, given that more than 75% of 13]. Mechanisms by which exercise the glucose uptake in response to insulin is delivers its desired effect include improving by the muscular tissue. The fatty acids endothelial function, decreasing the released from adipose tissue, concentrate vascular stiffness, improving left inside the myocytes and reduce the GLUT- ventricular diastolic function and, last but 4 transportation onto the cell membrane. not least, improving the systemic state of Exercise, however, will reduce the fatty inflammation. Exercise also helps reduce acid accumulation within the myocytes, by both visceral and peripheral fat mass [12]. oxidizing them. Therefore Life style 5-years follow up of 468 diabetic patients modification, by focusing on the weight showed that patients with lower aerobic loss and increase in the physical activity, capacity at the beginning of the study may prevent progression toward frank tended to have increased incidence of diabetes in people who have an impaired cardiovascular mortality and morbidity glucose tolerance test [5, 8, 9]. A study, [14]. which followed about 69000 female nurses Aerobic exercise with modest intensity can for up to 16 years, revealed that obesity and improve the VO2 Max up to 10% in Type II sedentary life style are independent risk diabetics. This would result in a significant factors for developing type II diabetes [10]. decrease in the risk of cardiovascular diseases [15]. A recent study, designed to Controlling the blood sugar levels: evaluate the effect of aerobic exercise on Regular exercise can not only lower the the plasma levels of inflammatory amount of HbA1C in diabetics [5], but also biomarkers and other indicators of vascular would decrease the prevalence of endothelial dysfunction in obese patients hyperglycemia in these patients. A meta- with type II diabetes, showed a remarkable analysis of 14 clinical trials (12 studied decrease in these factors and also increase aerobics and 2 evaluated resistive exercises) in serum HDL levels following only two revealed that regular exercise may lower the weeks of exercise without any dieting [16]. HgbA1C to a level that could ultimately be Exercise may also improve the state of effective in prevention of developing anxiety or depression which is commonly hyperglycemic complications [11]. A recent seen in patients with chronic diseases like trial evaluated the effects of one session of diabetes [5, 12]. exertion in reducing serum levels of glucose in diabetic patients. This study showed that As time passes, the effects of physical total time of hyperglycemia, may decrease activity in prevention and control of type II about 40% up to 24 hours after each session diabetes are more and more revealed. of exercise. Researchers determined that the However, like in other disease, one must effect of this exertion in reducing also learn about the potential hazards of postprandial hyperglycemia equalizes the exercise therapy. The team, who manages effect of limiting calorie intake or use of anti diabetic patients, must constantly evaluate hyperglycemic drugs in these patients [8]. the pros and cons of the prescribed exercise routine and modify it as needed. This team Related disorders: Regular exercise in consists of patient, physician, nurse, diabetics has many beneficial effects other dietician and psychologist and preferably a than improving serum glucose levels as it sports medicine specialist [12, 17]. also improves their cardio-respiratory Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008, 5

Table 1. The Effects of Regular Exercise on DM II [5] Glucose Metabolism:

Insulin Function Improved

HbA1c Level Decreased Lipid Profile: Total Cholesterol Unchanged HDL Increased LDL Decreased or Unchanged VLDL Decreased Total Cholesterol/HDL Decreased Cardiovascular System: Cardio-respiratory Fitness Improved or Unchanged Resting Heart Rate Decreased Heart Rate at Submaximal Exertion Decreased Blood Pressure (in Mild - Moderate Cases) Decreased Anthropometric Changes: Body Weight Decreased Fat Mass (Particularly in Obese Individuals) Decreased Fat –free Mass of the Body Increased or Unchanged Psychological Features: Self- concept Improved Self- esteem Improved Depression Decreased Anxiety Decreased Stress Response Decreased

Table 2. Indications of Performing Exercise Tolerance Test Prior to Exercise

• Age>35 yrs • Age> 25 yrs (if more than 10 yrs DMII or more than 15 yrs DMI) • Any Other Cardiovascular Risk Factor Such As High BP, Smoking , Disordered Lipid Profile, Sedentary Life Style, etc. • Microvascular Diseases (Proliferative Retinopathy or Microalbuminuria) • Peripheral Vascular Disease • Autonomic Neuropathy 6 Hassabi et al.: Exercise Prescription in…

Prescription for a Diabetic Patient [17]

Table 3. Classification of Physical Activity (<1hr) Intensity [17]

Relative Intensity

Intensity % Max HR (220-age) %VO2 max Borg Scale

Very Mild <35 <20 <10

Mild 35-54 20-39 10-11

Moderate 55-69 40-59 12-13

Hard 70-89 60-84 14-16

Very Hard >90 >85 17-19

Maximal 100 100 20

Evaluations prior to initiating the with a sub-maximal constant-workload. exercise program These tests may not be necessary for those diabetics who are at low risk for Before starting an exercise program with cardiovascular disease and may intensity higher than daily activities, inadvertently lead to extra costs which in diabetic patients should be precisely turn could reduce patient's compliance with evaluated for potential limitations and exercise [18]. Anyhow, for the time being, possible contraindications to the exercise adhering to current guidelines is logical routines [17, 18]. These evaluations consist unless newer evidence and of a good clinical history, physical exam recommendations arrive. and a diagnostic work-up to evaluate for For those diabetics who do have no specific the presence or absence of macro-vascular electrocardiographic response to exertion or or micro-vascular complications of those with baseline ST-T changes at rest, diabetes. One must pay close attention to supplementation of the exercise tolerance signs and symptoms of cardiovascular, test with nuclear cardiac imaging is ophthalmologic, renal and neurologic recommended. Patients with known cardiac complications of diabetes [17]. disease must be evaluated during exercise for any myocardial ischemic response, Cardiovascular complications in diabetes: threshold of ischemia onset, and tendency Given that many of diabetics suffer from for exercise-induced arrhythmias [17]. frank or silent coronary diseases, there is a The physician prescribing mild intensity risk of pathologic response to the exercise. exercise (requiring less than 60% Max HR) Silent ischemia prevalence in diabetics is like slow walking must use their clinical up to 25% [12]. Thus, it is reasonable to judgment to decide on whether or not pre- further evaluate diabetics who fit in with screening with exercise tolerance is needed one of the table-2 conditions and want to [17]. join exercise routines with moderate or higher intensities (Table-3), and also with Peripheral vascular diseases: exercise tolerance test [12]. Exercise Evaluation for peripheral vascular disease tolerance test is done with aerobic exertion in diabetics is based on related symptoms Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008, 7 and signs. These symptoms and signs is cardiac, this is referred to as include claudication, poor distal pulsation cardiovascular diabetic dysautonomia. The in the affected extremity, subcutaneous clinical signs of cardiovascular atrophy and hair loss in the affected dysautonomia includes silent myocardial vascular territory. One must note that ischemia or infarction, inappropriate resting presence of the dorsalis pedis and posterior tachycardia or early onset of tachycardia tibialis pulsation dose not exclude presence with exercise, reduced maximal heart rate, of distal ischemia in the foot. Thus, if there decreased exercise tolerance, hypotensive is any suspicion of distal limb ischemia, response to resistive exercises, impaired further evaluations such as Doppler control of body’s temperature, increased ultrasonography will be indicated [5]. incidence of dehydration and impaired noradrenergic response to hypoglycemia Diabetic retinopathy: [5]. Thus during physical examination of a Annual ophthalmic exams should be done diabetic patient, one must pay close routinely in all diabetics. Presence of attention to patient’s heart rate, orthostatic diabetic retinopathy indicates a closer hypotension ( a positional drop of more interval of ophthalmic eye exam every six than 20 mmHg in blood pressure upon months. Progression of retinopathy to standing) and other signs of dysautonomia proliferative stages requires even closer involving the skin, pupils, gastrointestinal follow-up. If one is intending to evaluate and genitourinary systems. diabetic patient with proliferative Myocardial thallium scanning is a non- retinopathy with exercise tolerance test, it invasive method to evaluate the extent of is recommended to use a sub-maximal coronary involvement in these patients. protocol [5]. Also for exercise tolerance testing in this patient, a sub-maximal protocol is Diabetic nephropathy: recommended [5]. About 20-30% of diabetics will suffer from diabetic nephropathy. The incidence of Psychiatric evaluation in diabetics: nephropathy increases with longer duration One must not forget about the role of of diabetic state. Thus, in type I diabetes, psychiatric evaluations in succeeding with screening for nephropathy should begin the exercise therapy. Patient or their five years after diagnosis is made. In type II acquaintances may have a diabetes, patient must be screened for misunderstanding about exercise in the proteinuria once diabetes is diagnosed [19]. context of diabetes. Depression is more common in those with chronic diseases and Diabetic peripheral neuropathy: it may prevent initiation of exercise therapy Peripheral neuropathy typically involves in diabetics. Thus by appropriate the distal parts of extremities particularly psychological evaluation and intervention the lower legs and feet, causing loss of in diabetics, there would be better chance sensation in the affected area. The affected of starting an exercise therapy and persons are more prone to foot ulcers [5, compliance with it [20]. 19]. A thorough pre-participation evaluation of a diabetic person should Prescribing exercise in type II include sensory and proprioceptive diabetes examinations. As previously said, physical activity has Diabetic autonomic neuropathy: tremendous benefits in patients with type II This complication of diabetes diffusely diabetes. Recent studies emphasize on the impairs all autonomic functions in the importance of long term exercise programs body. When the involved autonomic system in prevention and management of this very 8 Hassabi et al.: Exercise Prescription in… common metabolic disease. There is good intensity ( corresponding to 40-60% evidence in those with impaired glucose VO2 Max or 50-70% Max HR) or at least tolerance, showing that increasing the daily 90 minutes per week of intense aerobic physical activity along with some weight exertion is recommended. This volume loss leads to lower incidence of progression of exertion is done best if divided in at toward frank diabetes [18, 21]. For those least 3 days a week without longer than with impaired glucose tolerance, it's 2 days of rest in between each session. recommended to not only limit daily caloric Minimizing the day to day variance of intake but also to have at least 150 minutes physical activity in diabetics, eases the per week, of moderate to intense physical regulation of their diet and antiglycemic activity. A meta-analysis of 27 clinical drug regimen. Thus it is preferred to trials on different exercise protocols space the aerobic exercise sessions in as (aerobic, anaerobic or a combination of many weekdays as possible. Also for both), showed a significant benefit in those patients with advanced age and or diabetics, as evident by decrease in serum sedentary lifestyle, one may divide each levels of HgbA1c. This beneficial effect session of daily exercise into 2 or 3 was comparable with the benefits gained by smaller sub sessions and distribute them dieting and medical therapy for diabetes evenly throughout the day. [22].
Performing 4 hours or more of The best way to control ones weight in the aerobic and or resistive exertion with long term, is a combination of diet, exercise moderate to severe intensity, reduces and behavioral changes. Exercising alone, incidence of cardiovascular events without limiting the daily caloric intake and more, compared with less intense behavioral changes, may lead to loosing up exercise protocols. to 1kg at best. The reason for this limited
For long term maintenance of weight loss in obese patients is that they significant weight loss (more than usually have difficulty with adhering to the 13.5kg), larger volume of exertion, like needed amount of physical activity and also 7 hours a week of moderate to intense that they tend to compensate for their physical activity may be required [18]. burned calories by increasing their caloric intake and decreasing their overall physical Activities like walking, bicycling and activity throughout the rest of the day. swimming are examples of the aerobic However, one must note that the weight exertions that are well accepted among loss achieved by exertion results in higher many diabetic patients [12]. insulin sensitivity when compared to the same amount of weight loss achieved by Despite the known benefits of aerobic dieting. Also of note that the amount of exercise, some practical limitations do exertion needed to achieve significant exist. Some patients consider these routines weight loss in the long run is much more redundant and boring [18]. On the other than what is needed to control serum hand, performing such trainings may be glucose levels [18]. difficult for those with sedentary life style The intensity and amount of aerobic and/or obesity. In one study, only 28% of exercise needed depends primarily on one’s the diabetic population could adhere to therapeutic goal: these routines and recommendations [23]. Unfortunately, those who may gain the
In order to suppress serum glucose most benefit out of therapeutic exercise levels, lose weight, and reduce risk of routines are those who also have the most cardiovascular diseases, an exercise difficulties performing them. Realistically, protocol consisting of at least 150 diabetic patients who suffer from obesity, minutes per week, with moderate joint diseases and/or other accompanied Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008, 9 complications of diabetes, may have one must use drills that involve all groups difficulty with even 20-30 minutes of of large muscles. By definition, the ideal walking. Perhaps, for this group of number of repetitions for each move is 10- patients, one may use a host of other 15 times against a moderate resistance physical activities which have same (about 30-50% of 1RM) [12, 23]. Once the metabolic effects as aerobic exercise [23]. person becomes capable of completing 15 repetitions against a given resistance, then Resistive exercises have been suggested one could gradually add to the resistance recently, as a safe and effective therapeutic [12]. Studies have shown that by using tool in treatment of many chronic diseases higher resistance, the lowering effect on like diabetes. As per available data, these the HgbA1c becomes even more prominent. types of trainings, same as aerobic routines, Thus, for patients with good physical are very effective in improving insulin condition, the physician may prescribe sensitivity [21, 23, 24], increasing daily heavier resistance and subsequently less caloric consumption and improving one’s repetitions (like reps of 8-10 times) [18, quality of life [23,25,26]. Other than the 23]. Perhaps, exercise using resistance aforementioned benefits, resistance training machine is preferred over using free potentially improve muscular strength, weights, given that it's easier and safer increase body fat-free mass, improve bone [12]. mineral density and decrease symptoms and signs of arthritic diseases, all of which There is some data suggesting that using a result in rapid improvement of patient's combination of aerobic and anaerobic functional capacity. Patients usually find exercises may have a synergistic effect [8, this as an early reward for their hustle 28]. Recently following a randomized which in turn leads to improvement of their clinical trial involving 251 adults, self-confidence [12, 18, 23]. Given that researchers demonstrated that combining daily resistive exercises usually consist of aerobic with resistive exercises improves various activities, some patients find them patients’ serum levels of HgbA1c more more exciting and easier to adhere to [18]. prominently than using each exercise modality alone [29]. However, these A clinical study on the effect of resistance studies do have some limitations that training in improving the serum levels of warrant further research to shed some light HbA1c in type II diabetics suggests that on the correct answer [23]. performing these routines in a gym or recreational centers has higher success Flexibility or stretching exercises, are often compared with performing the same recommended to increase the joints range exercises in one’s home [27]. of motion and decrease potential of injuries It’s prudent to realize that resistive exercise like muscle strain. Though some of routines, as opposed to simple aerobic previous studies found that these trainings exertions, may require machines and are ineffective in decreasing the risk of understanding of the correct techniques such injuries [30], but one most keep in used for each move. Thus, in order to mind that many of these studies were done incorporate resistive exercises in one’s on younger populations and thus the results daily schedule, one must search for the of such studies may not be attributable to more practical and cost-effective measures other age groups [18]. Altogether, it seems [23]. that performing these trainings accurately If no contraindication is present, type II can result in increasing muscular flexibility diabetics must practice resistive exercises and joints range of motion. Since diabetes for at least 2 sessions a week or up to 3 may be associated with increased limitation sessions per week. In each practice session, of joints range of motion, probably use of 10 Hassabi et al.: Exercise Prescription in… flexibility exercises is beneficial in these activity in patients who take insulin patients. It is recommended that during secreting agents like sulfonylurea may lead stretching, muscles be gradually extended to hypoglycemia [18]. In general, etiologies to the point that patient feels the extension of hypoglycemia during the day include but no pain. Each stretch is better to last for inappropriate diet, delay or missed meal, about 30 second [1]. use of alcohol without sufficient carbohydrate intake and physical activity. Same as in non-diabetics, exercise for Physical activity is of particular interest diabetics, must begin with a warm-up, here, given that it is the only factor with the followed by elastic exercises and end with most variation during daily living [32]. a cool-down period. Warm-up should Glucose expenditure may increase many consist of 5-10 minutes of light aerobics folds during intense physical activity and (slow jogging, stationary bicycling, etc) in may continue for up to 15 hours post order to prepare the target muscles and the exercise. Thus exercise-induced cardiopulmonary system. Next, the target hypoglycemia may occur with some delay muscles should be slowly stretched for 5- after workout. Occasionally this 10 minutes and then to proceed with the hypoglycemia may occur as late as the next main exercise course. At the end of main morning of an afternoon session of exercise exercise course, there must be a cool-down [32]. Exercise-induced hypoglycemia is period of 5-10 minutes. This cooling period most likely to occur 6-14 hours post consists of similar activities as in the exertion [31]. However, this is a minimum warm-up phase, and is intended to risk in the type II diabetics, who are not on gradually decrease the heart rate to pre- insulin or insulin secreting agents. For type exercise level [31]. Having said that, for II diabetics, who are on insulin or insulin patients who have had a sedentary life secreting agent, it is recommend taking style, longer durations of warm-up and some carbohydrate prior to exercise, if their cooling must be considered [1]. serum glucose level is less than 100mg/dl. Perhaps, this precautionary measure is not needed for those diabetics who are on metformin, alpha-glucosidase inhibitors or Exercise in none euglycemic thiazolidinediones and not using insulin or insulin secreting agents. Same applies to states those diabetics how control their diabetes
Hyperglycemic state: American only with a diabetic diet. Anyhow, it is diabetic association recommends caution advisable to have some carbohydrate toward exercise if serum glucose exceeds supplements available prior to exertion [12, 300mg/dl. In the presence of ketonemia, 18]. serum glucose levels above 250mg/dl Few points to remember for preclude participation in exercise routines. exercise in diabetics Some experts believe that using a cut-off value of 300mg/dl without ketonuria for
Appropriate footwear: Perhaps shoes type II diabetics is too conservative and are the most important exercise equipment thus recommend light to moderate intensity used in diabetics. Appropriate shoes protect exercises to improve serum glucose levels the skin and may decrease the recurrence of [18]. Accordingly until arrival of newer diabetic foot ulcers [33]. It’s prudent that guidelines, clinicians must adhere to these physicians observe patients habits and recommendations for prescribing exercise behaviors toward their footwear. Physician protocols in diabetics. must also recommend appropriate footwear for exercise along with proper modes of
Hypoglycemic state: Increased physical exercise for diabetics with diabetic foot Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008, 11 neuropathy [34]. Many of the aerobic must discard any worn out footwear. exercises like walking and jogging require Diabetic patients may choose shoes appropriate shoes. Shoes, if inappropriate, appropriate for the type of their intended may result in impaired blood perfusion to exercise. In regard, the surface on which the foot and inflammation resulting from patient is to exercise should be considered recurrent focal pressure. The combination when choosing the footwear [35]. A good of aforementioned mechanisms may even time to ensure if patient has obtained lead to foot ulceration. If patient fails to appropriate footwear at the time of physical recognize and treat diabetic foot ulcer, it exam prior to beginning the exercise may easily become infected and deepen routine [36]. further [35]. Diabetics with neuropathy must wear shoes
Adequate hydration: It is prudent to with thick bottom layer. They may also adequately hydrate diabetics during frequently examine the internal surfaces of exercise. Dehydration may lead to various their shoes and look for foreign bodies. detrimental effects in a diabetic. First, Walking barefooted on hot sidewalks, blood glucose concentration will increase around the pool or inside hot showers may as the body dehydrates during exertion. be dangerous as it may lead to severe burns Second, diabetics with autonomic on their soles. neuropathy are prone to hypotension For aerobic exertions, the American following exertion if dehydrated. Also diabetic association recommends use of given that most of the type II diabetics are silica gel or air orthoses in the mid sole part obese and obesity is a precursor for of shoes in order to minimize foot injuries. dehydration and heat exhaustion, thus it is Also recommend is use of polyester or essential to pay close attention to maintain cotton blend stockings, which helps to keep adequate hydration during exercise. foot dry and prevent it from blistering. One Adequate rehydration may be achieved by must always wear clean and dry stockings drinking 500 ml of fluids about 2 hours when exercising and then exchange the prior to the activity. During the exercise as sweaty stockings and dry up his feet after well, one must drink fluids frequently with each session. The moist stockings are short intervals, enough to compensate for hazardous given that it may become the amount of fluid lost with perspiration. infected with fungi. Caution is advised with exertion in the cold Impaired blood perfusion to the feet as a or warm climate [37]. Diabetics must avoid result of stiff footwear is a common exercising in the hot and under direct sun etiology for foot injuries. Many times, light [5]. when shopping for shoes, diabetics with neuropathy may assume that the shoe they are trying is too tight and thus request a Exercise precautions in diabetics smaller size shoe. Tight footwear is affected by diabetes complications dangerous given that it may easily lead to ischemic pressure ulceration. These Since there are limited studies about the patients need to wear shoes with enough pros and cons of exercise in patients who space around the toes to prevent friction suffer from complications of diabetes, thus, and blistering in the toes. In general, leather most of recommendations in this field are is preferred to plastic given that it molds to based on expert opinion [18]. Diabetic the foot and allows air exchange between complications do not contraindicate the foot and the surrounding air. New exercising as the benefits of light to footwear must be initially worn for short moderate intensity exercise outweigh its periods until they soften and then foot must potential hazards [5]. Here we will review be evaluated for any pressure points. One the potential complications associated with 12 Hassabi et al.: Exercise Prescription in… exercise. reduce the exercise risk in diabetics. Daily surveillance of the foot and appropriate
Diabetic retinopathy: Exercise and management of the minute foot injuries, physical activity have no known (like, aberrations, erosions, blisters and detrimental effect on vision or progression long lasting ulcers) and, also, foot of the non-proliferative retinopathy and infections like fungus infections, will macular edema. This applies to both reduce the potential for formation of aerobic and resistive exercises [18]. In diabetic foot ulcerations in patients with severe non-proliferative retinopathy and peripheral neuropathy [39]. also the proliferative type, any exercise activity requiring to hold one’s breath for
Autonomic neuropathy: Autonomic long duration or those leading to increased neuropathy may lead to reduced cardiac systolic blood pressure over 160 mmHg are response to exertion, orthostatic prohibited. These patients must also avoid hypotension, gasteroparesis, impaired exercises like gymnastics which positions thermoregulation, reduced night vision and patient’s head below the trunk [5]. impaired thirst sensation. These will all increase risk of exercise induced
Peripheral neuropathy: Patients derangements in diabetics [18]. In order to affected with peripheral neuropathy must adjust the level of physical activity, the avoid exercises like long distance walking affected patients must use the RPE measure which may inflict injury to the foot. Also rather than the heart rate. Heart rate in these routines that require excessive balance are patients may not correlate well with the not appropriate for this group of diabetics. intensity of exercise. It is best to start the Sports that require less weight bearing like aerobic routines of such patients with only swimming and cycling are more 50% of their potential and then gradually appropriate for these patients [18]. increase it as tolerated [12]. These patients However, some diabetics with neuropathy as mentioned earlier are prone to actually do prefer exercise modes which dehydration and hypothermia, as a result of have more weight bearing. Researchers impaired thirst and temperature regulation have shown that increasing weight bearing [5]. Given that these patients may have activities are not associated with increased difficulty in sensing symptoms of risk of diabetic ulceration recurrence. hypoglycemia, thirst and hypotension, close Finally more studies are needed to ascertain monitoring during physical activities is the most appropriate exercises in this highly recommended [6]. patient population [38].
Diabetic nephropathy: These patients
Sports and diabetic foot: Weight must adhere to light exertions and avoid bearing exercise modalities like long any physical activity like weight lifting distance walking, slow jogging, and which requires one to hold his/her breath running on the treadmill are not and also may lead to elevation of their recommended for those who suffer from systolic blood pressure [5]. diabetic foot. For those with active ulceration who intend to exercise during
Hypertension: It's recommended to their recovery, we do recommend activities lower patient's blood pressure prior to involving upper extremities like using an exercise, if systolic pressure exceeds 160 arm ergometery, etc. This group of patients mmHg or for diastolic blood pressure more must also avoid water sports until the than 100 mmHg [12]. This group of diabetic ulceration has fully healed [35]. diabetics should avoid heavy and strenuous Identifying high risk patients with diabetic physical activities and instead adhere to foot ulceration is an important step to more dynamic activities which involve Iranian Journal of Diabetes and Lipid Disorders; Vol.8, 2008, 13

large groups of muscles with light to prohibited from physical activity, but as a moderate intensity (like bicycling, biking, rule of thumb, physician must always etc). Recommendations for hypertensive evaluate this group, prior to any change in patients must also be followed. the level of daily activities and modify the prescribed exercise routine as needed. For the physicians, using simple phrases, CONCLUSION like “walk somewhat more”, are not beneficial. Patients must be adequately Exercise is an important measure of educated in this regard. The prescribing primary and secondary prophylaxis in type physician must tailor an exercise routine II diabetes and it also helps regulate blood which fits patient’s physical condition and sugar in these patients. Other than also is compatible with her/his regulation of glucose metabolism, regular psychological and social situations. This exercise harbors many somatic, mental and will improve patient’s motivation and social benefits in diabetics. compliance with the prescribed exercise While nowadays, even those diabetics who routine. suffer from diabetes complications are not

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