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.