Diabetes
Part 1: Pathophysiology of Diabetes
Learning objectives
From the literature review, the reader should be able to:
- Learn the facts and figures on diabetes, particularly in reference to mortality, medical costs and the disorder’s risk factors.
- Learn the pathophysiology of the disease, especially the organs that are vulnerable to attacks by the disease.
- Learn the role of the disorder in exercise intolerance, particularly why individuals with the disorder find it difficult to engage in exercise and strenuous physical activities.
Summary and Overview
Diabetes is one of the leading causes of death in the world with a burgeoning cost on the healthcare system; given the increased number of cases occasioned by inactivity and increased obesity. Although exercise presents one of the ways of managing the disorder, the effect of the disorder on exercise intolerance presents a problem. It is for these reasons therefore, that the pathophysiological analysis of the disorder is important. This is especially in relation to exercise and its role in the management of the disorder.
Commentary
Data relating to diabetes point to the gravity of the disorder as in relation to the medical cost and its effect on the population. The fact that the disorder is among the leading causes of death in the world, its role in the number of hospital days and the medical costs is a cause for alarm for medical practitioners and the wider population. Moreover, given that the prevalence of the disorder is not anywhere near abating, is even more cause for worry. With an estimated $100 million in direct and indirect cost as of 2001, which increased to $250 million as of 2010, and with an escalating number of new cases, diabetes stands as one of the most challenging health problems worldwide.
The disorder’s risk factors include family history, obesity and old age. Although type 1 diabetes is less common, type 2 (the more common of the two), has a strong genetic component and is easier to modify, with focus on its risk factors. Obesity and physical inactivity, which are some the disorder’s risk factors, are adjustable factors amenable through physical exercise. Physical exercise moreover, has corrective characteristics to the disorder, especially when coupled with proper diet intake.
The role of exercise in the management of the disorder, while important, is curtailed by the disorder’s effect on vital organs such as the heart, kidney, and blood vessels. This presents challenges for its management, given that inactivity exacerbates the development of the disorder. It is for this reason therefore that preventive measures against the disorder are more effective. Physical activity is important to not only the diabetics, but also for the non-diabetics as a measure of preventing diseases and keeping fit.
Pathophysiological Analysis
Diabetes is amongst the leading causes of death in the world. The disorder accounts for about 10 percent of acute hospital days, with more than $100 million in direct and indirect medical costs (Chipkin, Klugh&Chasan-Taber, 2001). Some of the risk factors for the disorder include age, family history, obesity and inactivity. For type 2 diabetes, physical exercise is a major determinant, with increased vigor in the activities evidenced to improved insulin sensitivity and glycemic control for nondiabetics as well as for type 2 diabetics (Chipkin, Klugh&Chasan-Taber, 2001). However, research indicates that the presence of diabetes greatly reduces exercise tolerance in patients, particularly diabetic with heart failure and claudication (Green, Askew & Walker, 2007).
Diabetes has adverse effects on the vascular system, causing exercise intolerance. Exercise intolerance herein refers to the inability of an individual to exert the body physically for a duration, or intensely for what is considered normal for a person of the specific age. Limitations for the individual’s exertion may include shortness of breath, pain or weakness. Vinik and Ziegler (2007), indicate that diabetes causes complications on the cardiovascular autonomic neuropathy, a factor that causes impairment to the autonomic nerve fibers, which are important in the innervation of heart and blood vessels. The results of this are abnormalities in the heart rate control and the workings of the vascular system. The two are important factors in exercising, and the abnormalities therefore make it difficult (Vinik& Ziegler, 2007). At the core of cardiovascular autonomic neuropathy (CAN) is autonomic dysfunction, which is a factor in impairing exercise tolerance. Intolerance in this case is a consequence of the dysfunction affecting other cardiovascular functions such as reducing heart rate responses and blood pressure, as well as blunting the increases in cardiac output during exercise (Vinik & Erbas, 2002).
Further, diabetes is a major cause of atherosclerotic peripheral arterial disorder (PAD) and claudication. According to Green, Askew and Walker(2007), claudication refers to ischemic muscle pain largely induced by exercise. The pain is usually exercise limiting and felt when walking or cycling in the calf and quadriceps respectively. Claudication is caused by changes in “atherosclerotic narrowing of one or more of the major arterial vessels feeding the lower limbs, i.e. aorta, iliac, femoral, popliteal and/or tibial arteries, resulting in areduction of the maximum blood flow to the lowerextremities during exercise” (Green, Askew & Walker, 2007, p. 860). This is in addition to microcirculatory, neuromuscular and metabolic alterations that happen to the lower extremities’ skeletal muscles, all of which potentially cause exercise intolerance to the diabetes patients.
Even in the absence of CAN and PAD, diabetes impacts exercise tolerance. Green, Askew and Walker (2007) report that exercise tolerance and cardiorespiratory fitness are all weakened for type 2 diabetes patients due to the changes in glucose concentration that occur during and after exercise. Thus, diabetes type 2 leads to the development of cardiovascular complications, which invariably exacerbate different complications in patients, and ultimately reduce exercise tolerance (Chipkin, Klugh&Chasan-Taber, 2001). Moreover, with the continued development of the disorder, many of the small blood vessels of the patients lose their response to the signals from the body, which also cause problems with blood flow. Consequently, with an ineffective flow of blood, most of the muscles do not get enough energy given the lapses in signals from the different parts of the body. Patients, for that reason, become exercise intolerant, as muscles continually lack the energy (due to inefficient metabolism of glucose) necessary to support the increased demand for energy from the muscles.
Diabetes’ role in exercise intolerance stems from the damage of important organs that support strenuous physical activity. With the heart, blood vessels, kidneys and nerves failing, it is almost impossible for patients with the disorder to take part in strenuous physical activity, let alone exercise. Moreover, the disorder also leads to impairment of other body functions, such as the endothelial function, which largely leads to the impairment of the heart’s left ventricular diastolic function, leading to exercise intolerance (Sugimoto et al., 2014).
Exercise presents one of the many ways in the management of diabetes, especially for obese and overweight individuals. Through exercise, individuals are capable of managing their weight and reducing the risk factors involved in the development of diabetes. However, for individual with diabetes, the disorder presents a challenge with exercise. The disorder (diabetes) largely results in organ failure, most of which are vital to exercise and undertaking strenuous activities. Moreover, diabetes makes individuals vulnerable to other medical conditions such as CAN and PAD, all of which degenerate to severe exercise intolerance to the patients.
References
Chipkin, S., R., Klugh, S., A. &Chasan-Taber, L. (2001). Exercise and diabetes.Cardiology Clinics, 19(3), 489-505
Green, S., Askew, C., D. & Walker, P., J. (2007). Effect of type 2 diabetes mellitus on exercise intolerance and the physiological responses to exercise in peripheral arterial disease. Diabetologia, 50, 859-866
Sugimoto, T. et al. (2014).Left Ventricular Diastolic Dysfunction and Exercise Intolerance in Type 2 Diabetes Patients With Endothelial Dysfunction.Circulation, 130, 125-132
Vinik A, Erbas T. (2002). Neuropathy. In Ruderman N, Devlin JT, Schneider S, Kriska A, eds. Handbook of Exercise in Diabetes. Alexandria, VA: American Diabetes Association
Vinik, A., I. & Ziegler, D. (2007). Diabetic cardiovascular autonomic neuropathy. Circulation, 115, 387-397
Part 2: Exercise as Medicine
Learning Objectives
From the intervention and recommendations herein, the reader should be able to
- Discover the importance of physical exercise and activity for people with and without diabetes.
- Discover the different types of exercise available for people with diabetes
- Discover the benefits of resistance exercise, particularly in relation to each of the recommendations given, and from the justifications of each recommendation
Summary and Overview
Exercising is one of the ways of managing diabetes. Aerobic exercise is one of the best ways of managing diabetes. However, with difficulties that some people may experience in undertaking aerobic exercise given the vigor involved and the potential complications for such individuals in case they engage in aerobic exercises, resistance exercise offers an alternative means with similar results. Resistance training offers not only a means of engagement in physical activity, but is also suitable for the obese (who may find it difficult in moving muscles in aerobic exercise) and individuals with other cardiovascular complications. By following these recommendations, it is possible to gain similar or even better results as aerobic exercises for individuals with diabetes and other cardiovascular complications.
Interventions and Recommendations
One of the risk factors for type 2 diabetes is inactivity, which mostly leads to excess weight and obesity. Studies have however shown that regular exercise, particularly aerobic exercise, improve glucose control, boost insulin sensitivity as well as improve cardiovascular autonomic risk factors such as arterial stiffness and visceral adiposity (Eves &Plotnikoff, 2006; Hordern et al., 2012). Recommendations by the American Diabetes Association encourage at least 150 minutes in exercises of moderate intensity, which go a long way in improving glycemic control, prevent cardiovascular disease, regulate obesity as well as improve fibrinolysis, especially for diabetes patients (American Diabetes Association, 2004). While most of these patients would benefit from these physical exercises, many find it difficult to engage in the intense exercises due to challenges such as pain, obesity and other complications (Eves &Plotnikoff, 2006). It is for this reason that other forms of physical activity come in handy for such patients.
One of the alternative means of physical activity is resistance training; this is a useful exercise used in the management of a number of chronic diseases, proven safe and effective for use by the elderly and individuals with obesity (Eves &Plotnikoff, 2006). Through its use in an exercise regimen, resistance exercise creates an all-encompassing program, which enhances muscular conditioning, improving health, physical ability and athletic performance (Marwick et al., 2009). It is however important to follow guidelines in the performance of the resistance training to avoid injury and hypoglycemia in addition to other risks.
Recommendations by the American Diabetes Association indicate that patients put to use free weights, resistance machines and bands as well as isometric and calisthenics for muscular fitness. The use of such machines and exercises result in equal gains in the strength and mass of the muscles targeted by such exercises. Moreover, such exercises are instrumental in optimizing insulin action as well as controlling blood glucose (Marwick et al., 2009). Even more is than in the arrangement of the exercises, large muscles should get the first priority before the smaller muscles, with an additional preference for multiple joints before singular joints; this ensures there is enough energy for performance of all exercises towards all joints as well as avoid premature fatigue before exercising the main muscles (Hordern et al., 2012).
The intensity of the exercise should move from moderate to intense (Garber et al., 2011). While there is no specificity on the time accorded to the different intensities of the exercises, it is important to do the exercises to the point where it is difficulty to perform another exercise without assistance. While home-based exercises are good, supervised regimen are much better as they provide better exercises, which are well suited for sustaining blood glucose control and the optimization of insulin action.
For the duration of the exercise, it is recommended that individuals, particularly those coming out of sedentary lives to focus on the accumulation of at least 1000 kcal a week in energy expenditure. This is equivalent to 30 minutes of moderate-intensity activity performed in five days each week (Marwick et al., 2009). Notable however, is the fact that higher energy expenditure has better results. Thus, for the improvement of cardiovascular risk, 150 minutes a week of moderate intensity physical activity is recommended for diabetics (Marwick et al., 2009). This is in addition to engagement at least thrice a week of resistance training, with all the exercises involving all the muscles of the body to improve the results. Resistance training should largely be staggered between 48 hours of rest to provide the body with enough time to adjust before engaging in similar exercise.
Even in the engagement of patients in the exercises, it is important that the exercises progress slowly in intensity, frequency and the amount of time dedicated to the training. In the performance of resistance training therefore, the first increases should involve the weights and resistance. Moreover, with the sessions lasting at least 30 minutes, there should be no more than 48 hours of rest between the exercises, which should gradually progress over time in intensity, regularity and the duration of each session (Marwick et al., 2009). The gradual progression is recommended as a measure against hypoglycemia, as well as giving the body enough time to adjust to the intensity, length of time and frequency of the exercises.
Resistance exercise holds many benefits to diabetics, and with regular engagement, people with the disorder can live better lives. With a minimum of two days in resistance training, patients can get better muscle mass, in addition to being able to prevent muscle mass and strength losses. With greater muscle mass, many patients are able to increase the levels of consumption of resting blood glucose as well as gain better glycemic control.
References
American Diabetes Association (2004).Physical Activity/exercise and diabetes. Diabetes Care, 27(1), 58-62
Eves, N., D. &Plotbikiff, R., C. (2006).Resistance Training and Type 2 Diabetes Considerations for implementation at the population level. Diabetes Care, 29(8), 1933-1941
Garber, C., E. et al. (2011).American College of Sports Medicine position stand.Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise.Med Sci Sports Exerc, 43 (7), 1334-59
Hordern, M., D. et al. (2012).Exercise prescription for patients with type 2 diabetes and pre-diabetes:A position statement from Exercise and Sport Science Australia. Journal of Science and Medicine in Sport, 15, 25-31
Marwick, T., H. et al. (2009).Exercise Training for Type 2 Diabetes Mellitus. Circulation, 119, 3244-3262