Type 2 Diabetes Therapy

If you have peripheral neuropathy be cautious of high-impact exercising and always keep an eye on the condition of your feet. Watch for any blisters or lesions and treat them appropriately. Frequent and generous foot care should be part of the daily routine of anyone with diabetes.

If you have any heart problems be sure to get specific instructions from your doctor regarding maximum heart rate, maximum blood pressure and symptoms to watch for such as extreme breathlessness, chest pain, joint pain etcetera. With an appropriate choice of exercise and a bit of planning most of these complications can be avoided.

A common risk that presents the most immediate concern for many individuals will be hypoglycemia (low blood sugars), either during or after exercising. To better understand this risk we need to understand the approaches to type 2 diabetes therapy. Perhaps a better understanding will eliminate some of the mystery and result in safer and healthier routines before, during and after exercise.

Last issue we categorized type 2 diabetes therapies based on the risk for low blood sugars. I have listed them on the following page as a reminder, and we will now discuss them in more detail in relationship to exercise. Refer to Table 3 for a list of symptoms associated with low and high sugars.

Symptoms of Hypoglycemia (Low Blood Sugar) and Hyperglycemia (High Blood Sugar)
Lows: Sweats Shakes Hunger Dizziness Fatigue Irritable Fast Heartbeat	Highs: Extreme Thirst Frequent Urination Dry Skin Drowsiness Blurred Vision

1. This first category representing the lowest risk will include individuals taking any of the following:
   1. No Diabetes Medications
   2. Metformin
   3. Acarbose
   Generally speaking when someone is first diagnosed with type 2 diabetes their physician or diabetes specialist will recommend a period of lifestyle modification (ie. diet and exercise); a minimum 6-8 weeks to see if average blood sugars can be reduced, that is a lowering of the HbA1c. Historically, prior to the discovery of insulin and the development of oral diabetes medications, this was the only way to treat type 2 diabetes. If lifestyle modification fails it will be recommended that some form of medical therapy be introduced. Typically this will be a drug called metformin that acts by reducing sugar output from the liver to help reduce the average blood glucose (BG) levels, especially morning fasting sugars which are often high as a result of an overactive liver during the night.
   
   A second drug Acarbose may also be used, either alone or in conjunction with metformin. This medication acts by reducing glucose absorption from the small intestine thereby reducing the blood glucose rise associated with food intake. In any of the above circumstances there is no danger of ever having a serious hypoglycemic reaction. In some rare circumstances the BG levels may go as low as 3.5 mmole/litre but the body would certainly respond by turning up sugar production and reducing insulin secretion to avoid a further decline in blood sugars. Therefore, if your therapy falls into this category you should never let a fear of low blood sugars deter you from pursuing physical activities. Also do not use the fear of a low blood sugar as an excuse for bingeing during or after exercise. You may get hungry during and/or after exercise but that is no reason to overreact or take in excessive carbohydrates. Take in healthy balanced nutrition, not just carbohydrates.
   
   
2. The natural progression of diabetes is such that BG control may deteriorate over time and another medication is often added, typically an insulin secretagogue. There is a wide range of these currently available but the underlying principal is the same. These drugs stimulate the pancreas to secrete more insulin. This second category of therapy includes the addition of a secretagogue, typically with metformin but sometimes without and poses an additional challenge in terms of BG management. The challenge is that when taking a secretagogue it is possible that the pancreas may produce too much insulin relative to the blood sugar and results in a severe decline in BG for which the liver cannot compensate. In this scenario BGs may go so low that a coma and possibly death can result.
   
   
3. Eventually there may be further deterioration of BG control and the addition of another medication called an insulin sensitizer (eg. Avandia) which makes the body more sensitive to the insulin it produces. This class of medications is proving to be an excellent therapy for many type 2 diabetics. In some cases it has been found effective as a first line medication. An insulin sensitizer taken alone poses little risk for a severe hypoglycemic event but if taken in conjunction with an insulin secretagogue, as is often the case, it will increase the possibility of a low BG since the body will now be more responsive to the insulin it produces.
   
   
4. Many people with type 2 diabetes eventually require or may even choose insulin injections to help them manage their blood sugars effectively. I say choose because some individuals would rather inject a hormone that would occur naturally in the body than introduce a variety of drugs that the body's liver must process. Insulin may be taken with or without oral diabetes medications. When taking insulin subcutaneously the risk of having a low blood sugar is increased, especially if it is fast-acting mealtime insulin. Even more so if insulin is taken with an insulin sensitizer such as Avandia.

These represent four therapy categories and if you have type 2 diabetes you will fit into one of them. Review your diabetes therapy and decide which category applies to you. This is meant to provide a guide for knowing what your relative risk is for hypoglycemia, especially during and after exercising, but also for activities such as driving and day to day living. Knowing what your risk level is helps you to take the necessary precautions for safety and also lets you manage your blood sugars effectively. Equally important you can live life to the fullest knowing your blood sugars are safely in range and you are prepared if they should dip into the unsafe range.

You should consider yourself at risk for low blood sugars if you are using either a secretagogue or injecting insulin. If by chance you are at risk for severe hypoglycemia during exercise be aware of what your blood sugar is before you start exercising and take appropriate action if you feel you are at risk of low blood sugars during your activity. Appropriate action may include a snack before the workout or simply having some carbohydrates with you just in case of a low or a severe low. If you have an exercise partner it is wise and considerate to inform them that you're diabetic and the appropriate action to take if a low BG occurs. Generally speaking you should pay attention to any symptoms of a low BG that you experience and take action early rather than waiting until a mere low BG becomes a severe low BG. Let past experiences be your guide. Do your low blood sugar episodes come on gradually or do they happen rapidly with only a small amount of warning time? Do you manage things better with a solid snack or does a liquid carb source seem to enable you to deal with the crisis better and avoid the overcompensating as often happens after a low blood sugar? Learn from your experiences and let the lessons empower you to manage your blood sugars effectively so you can enjoy exercise and life to the fullest.

Eric Norman is a research scientist investigating heart disease in post-menopausal women and in individuals with type 2 diabetes.

References

1. Exercise in patients with Type 2 Diabetes Mellitus. Horton, E.S.. Chapter 77 in Diabetes Mellitus: A Fundamental and Clinical Text. Second Edition. Editors Derck LeRoith, Simeon I. Taylor, Jerrold M. Olefsky. Lippincott Williams and Wilkins. 2000.
2. Fuel Metabolism, Exercise and Nutritional Needs in Type 1 Diabetes. Franz, M.J.. In Canadian Journal of Diabetes Care 22:4 pp 59-63.
3. High-Intensity Resistance Training Improves Glycemic Control in Older Patients With Type 2 Diabetes. Dunstan, D.W. et. Al.. 2002. Diabetes Care Vol. 25, No. 10. 1729.