Building Competency in Diabetes Education THE ESSENTIALS

TREATMENT MODALITIES: LIFESTYLE| 5-45

effects from heat compared to those without diabetes (198). Metabolic, cardiovascular and neurological dysfunctions associated with diabetes reduce the body’s ability to detect heat and impair its capacity to dissipate heat (199). The body’s ability to maintain core temperature at safe levels may be decreased due to reduction in sweating (199) and decreased skin blood flow (200). People with diabetes are at higher risk for heat illness, especially if they are elderly and/or have cardiac or pulmonary disease or autonomic neuropathy. Strategies to limit exposure to heat should be discussed with patients. When possible, exercise should be performed in cool environments or when temperatures are cooler, such as during the early or later hours of the day. Even when temperatures are not hot, people should be reminded of the importance of hydration. People with diabetes often become so preoccupied with preventing hypoglycemia that they forget to maintain hydration. Water is the most important nutrient needed during exercise. Dehydration can adversely affect BG levels and heart function. Those with uncontrolled diabetes are particularly prone to dehydration when exercising, especially on warm days. Water is essential for preventing dehydration; sports drinks or diluted fruit juices will provide carbohydrate and fluid. Hyperglycemia prior to exercise is a concern for people with diabetes. For those with type 1 diabetes, severe insulin deficiency, whether from insulin omission or illness, can lead to worsening of hyperglycemia with exercise. If BG is >16.7 mmol/L and the person does not feel well, blood or urine ketones should be checked. If ketone levels are elevated in the blood (≥1.5 mmol/L) or in the urine (2 + or ≥4 mmol/L), vigorous exercise should be postponed until insulin is given (with carbohydrate, if necessary) and ketones are no longer elevated. If ketones are negative and the person feels well, exercise does not need be deferred (194). For those with type 2 diabetes, exercise does not need to be postponed due to hyperglycemia, provided they feel well. If capillary glucose levels are >16.7 mmol/L, it is important to ensure appropriate hydration, especially if exercising in the heat. People should be alert to increased thirst, nausea, severe fatigue, blurred vision or headache (194). Fear of hypoglycemia associated with exercise is likely the biggest barrier to exercise for people with type 1 diabetes and to a lesser extent for those with type 2 diabetes who use insulin or insulin secretagogues. Hypoglycemia can occur during, immediately after, or many hours after exercise. Prolonged aerobic exercise increases insulin sensitivity in recovery for up to 48 hours (192). Several factors need to be considered for the prevention of hypoglycemia (see Chapter 8: Acute Complications of Diabetes). The ideal strategy will depend on the individual. 1. Timing of exercise and insulin action : Free insulin levels in people with type 1 diabetes tend to be lower before breakfast than at any other time of day. Therefore, one might expect less hypoglycemia in response to exercise before breakfast,