Type 1 diabetes is "insulin dependent diabetes." Natural supplies of insulin, produced in the pancreas, have failed and it needs to be replaced by regular injection. The reasons for this failure are uncertain, although an autoimmune response in combination with genetic and environmental influences have been suggested. The disease may run in families.
Type 1 diabetes usually occurs in childhood or early teens, which suggests the older name of "juvenile diabetes." However, it can occur in older people and it might then be called "latent autoimmune diabetes in adults" or LADA.
Differences Between Type 1 and Type 2Both diseases result in too much glucose in the blood, the health consequences of which can be serious if the amount of glucose (blood sugar) gets too high.
In type 2 diabetes, glucose may be high because even though insulin is present, it cannot store the glucose efficiently in muscle and liver. This is called "insulin resistance." Type 1 is always a result of having no natural insulin.
Type 2 diabetes is mostly a disease of lifestyle, although genetics probably also plays a part. Being overweight and unfit will make you more likely to get type 2 diabetes, which is mostly not reversible.
Over time, type 2 diabetics can lose some natural insulin supply until eventually they may require insulin injections just like type 1s.
Exercise and Weight Training for Type 1 Diabetics
In a separate article, I described a training workout with cardio and weights for type 2 diabetics. In this article I’ll discuss exercise for type 1 diabetics. It’s worth separating the two so that there is no confusion.
Having no natural insulin creates a problem, because when you replace it with injected insulin you don’t have the body’s natural adjustment mechanisms (homeostasis) to know how much is required; you have to work it out and adjust it for various circumstances.
One of those variables is how much and how intense the exercise you do. Most type 1 diabetics already know this because they will have been trained in the dynamics of insulin use from an early age, especially with regard to physical activity. Yet this information is also useful for fitness trainers who may have to train diabetics.
Getting the insulin dose wrong, especially taking too much, can cause blood sugar (glucose) to get too low, which is known as hypoglycemia. An occurrence of this is usually known as a “hypo” and is signaled by feeling faint or week, or even worse, unconsciousness and coma. Type 1 diabetics guard against this by always carrying some sweet food or drink that can correct a hypo by raising blood sugar. Failure to correct plummeting blood sugar can be very dangerous and even fatal.
Exercise can lower blood sugar independently of insulin action. In such cases, insulin dose, and perhaps food intake, need to be adjusted around exercise time. Further, the idea that exercise, especially high-intensity exercise, is not to be recommended for type 1 diabetics because of this danger, is still held by some medical personnel. Weight training might be seen as a form of high-intensity exercise.
Type 1 Diabetics and SportThese days, children, adolescents and adults with type 1 diabetes are generally not discouraged from doing sport because the benefits of physical activity for general health are well known and there may also be mild improvements in glucose regulation and insulin requirements with exercise. Many world class athletes are type 1 diabetics. Examples from the US are Gary Hall Jr in swimming, Jay Cutler NFL (Denver Broncos), Kris Freeman, skiing. In Australia, Steve Renouf, rugby and Monique Hanley, cycling, are examples.
Medical Advice Before Commencing Physical ActivityAll diabetics should get a clearance to exercise from their doctors, specialists, diabetes carers or educators. Insulin-dependent diabetics need special advice. Insulin or medication doses and food consumption habits will probably need modification.
Diabetic complications may require special consideration when it comes to exercise. Here is a list of some complications that might prevent exercise, or limit type, duration or intensity.
- Uncontrolled blood glucose - high or low
- Uncontrolled high blood pressure
- Unstable heart conditions
- Retinopathy (eye and sight condition)
- Peripheral neuropathy (nerve damage to extremities, foot ulcers etc)
- Autonomic neuropathy (nerve damage to internal organs)
- Microalbuminuria and nephropathy (poor kidney function)
For example, individuals with retinopathy or high blood pressure may be advised to avoid the valsalva movement in which an exercise is performed by forcibly exhaling against a closed airway and straining to lift a weight. This technique is not required in fitness training in any case.
People with diabetic nerve damage may be advised how to care for their feet and to look for foot ulcers and damage with exercise – or be advised on suitable forms of exercise.
Weight Training and Exercise WorkoutsNote the following statement from the American Diabetes Association’s Position Statement on Exercise and Diabetes (Type 1 Diabetes):
All levels of physical activity, including leisure activities, recreational sports, and competitive professional performance, can be performed by people with type 1 diabetes who do not have complications and are in good blood glucose control.
A weekly program, adjusted for existing fitness, age, goals and convenience could look like the following.
Day 1. Aerobic training - 30 to 45 minutes.
Day 2. Weight training – 45 to 60 minutes
Day 3. Aerobic training as for day 1.
Day 4. Aerobic training as for day 1.
Day 5. Weight training as for day 2.
Day 6. Aerobic training as for day 1.
Day 7. Rest.
Waden J, Tikkanen H, Forsblom C, Fagerudd J, Pettersson-Fernholm K, Lakka T, Riska M, Groop PH. Leisure time physical activity is associated with poor glycemic control in type 1 diabetic women: the FinnDiane study. Diabetes Care 2005 Apr;28(4):777-82.
Herbst A, Kordonouri O, Schwab KO, Schmidt F, Holl RW. Impact of physical activity on cardiovascular risk factors in children with type 1 diabetes: a multicenter study of 23,251 patients. Diabetes Care 2007 Aug;30(8):2098-100.