Diabetes and Physical Activity

In this condition, particular insulin levels produced by pancreatic cells fail to achieve desired metabolic outcomes. The body does not respond adequately to appropriate insulin concentrations and commences production of this hormone in escalating quantities. The aftermath of such interferences in carbohydrate metabolism is type 2 diabetes or impaired glucose tolerance. Type 1 diabetes is a consequence of damage to the Langerhans beta cells in the pancreas (due to immunological or idiopathic factors), which results in an absolute insulin deficiency. Type 2 diabetes develops progressively, with insulin insensitivity initially prevailing due to insulin deficiency, followed by a phase of secretion defect connected with insulin insensitivity. The advancement of type 2 diabetes is facilitated by genetic factors as well as other factors such as obesity, sedentary lifestyle, infections, and the aging process of the body.

During exercise, we consume multiple times more glucose than at rest.. Routine physical activities, however, lead to adaptive changes in the body, which results in lower levels of insulin in the blood of active individuals. This is influenced by two factors: on the one hand, the inhibition or improvement of insulin secretion by the pancreas and on the other hand, the accelerated production and processing rate of this hormone in the tissues. Despite the lower level of insulin production by the pancreas, the body's glucose tolerance increases. Regular physical activity increases the sensitivity of the tissues to insulin by increasing the number of receptors in the cell membranes of the muscles and improving the affinity of these receptors to insulin. Training increases the number of glucose transporters (GLUT4 protein), which allows glucose to be transported more quickly into muscle cells. With each training session, the concentration of enzymes responsible for phosphorylation, glycolysis, and the storage of glucose in the form of glycogen in muscle cells increases. This mechanism works in every healthy individual who regularly engages in sports. Thanks to this, occasional consumption of products with a high glycemic index is not harmful to health or figure. However, it is important to remember that the adaptation mechanism also works in the opposite direction - already after a few days without physical activity, the sensitivity to insulin can decrease, which is harmful to health.

Prior to engaging in physical activity, a person with diabetes should undergo qualifying tests, including a cardiovascular risk assessment and a diagnosis of complications. This includes an evaluation of peripheral blood circulation, visual organs, and the presence of protein and neuropathy. Other chronic diseases should also be considered, and diagnostic tests such as exercise tests with glucose monitoring, resting electrocardiogram, Obstructive Blood Pressure (OB), long-term blood morphology, lipidogram, and general brain tests should be carried out. Individuals with significant blood circulation disorders should take special precautions to prevent injuries and skin abrasions on the lower limbs, as well as frostbite during exertion in low ambient temperatures. Those with diabetic retinopathy should avoid anaerobic exertion, especially those involving breath-holding, as there is also a risk of stroke in the eye. Diabetics with diabetic nephropathy and microalbuminuria or proteinuria can engage in moderate physical activity, provided that blood pressure is controlled. For diabetics with peripheral neuropathy and numbness, activities such as sprinting, long-distance running, or cardio training in a standing position are not recommended. Instead, swimming, cycling, rowing, or seated exercises that significantly lessen the burden on the cardiovascular system are advised. In this case, strength training should also be excluded. It is also worth carrying out a diagnosis of coronary heart disease and remembering that hypoglycemia can occur in diabetics even several hours after training.

The following guidelines should be considered when planning workout sessions: Each workout session should begin with a low-intensity warm-up and stretching exercise to prepare the body for further activity (5-10 minutes); after the main part of the session, a cooling-down period should be conducted (about 10 minutes); training frequency: at least three times a week; as the training level increases, the number of training days can be increased; the main priority for each workout session is to systematically perform exercises to achieve body adaptation; exercise duration depends on the training level and the intensity of exercise (usually between 20 and 60 minutes); it is important to note that a workout lasting longer than one hour may lead to hypoglycemia; types of exercise: aerobic training (3-7 times a week): walking, running, cycling, swimming; resistance training (2-3 times a week): strength exercises with low resistance; static exercises are not recommended: those in which an isometric cramp occurs; training intensity: 50-70% VO2max (moderate) - to determine the heart rate that we should maintain during training, we can use the formula: HR wysiłkowy = 0,5 × (HR max − HR spoczynkowe) + HR spoczynkowe; HR max = 220 − age; control of intensity, e.g., with the Borg scale.

Generally speaking, individuals with diabetes need to be aware that: – there is a risk of delayed hypoglycemia, particularly after extended physical exertion; – they must consume a meal 1-2 hours before engaging in physical activity (especially those on oral hypoglycemic medications); – it is advisable to lower the dose of insulin that is active during exertion; – they should have an extra portion of carbohydrate sources readily available; – they are obligated to carry an identifier that informs of their condition; – they should participate in sports accompanied by another person who knows how to respond in case of hypoglycemia; – they need to ensure proper thermal comfort through appropriate attire and hydration during exercise.