Regular exercise has an important role in the treatment and management of diabetes. In general, the physical activity recommendations for healthy individuals apply to those with diabetes. That is, at least 150 minutes (preferably 300 minutes) of moderate-intensity aerobic exercise per week. The exercise program should also include strength training and flexibility exercises two to three times per week. Because variations in your exercise program may be needed based on your form of diabetes (e.g., type I versus type II), the severity of your disease, and the type and schedule of your medications, you should consult your health care professional prior to initiating an exercise routine.

Some special considerations associated with exercise and diabetes of which you should be aware include:

Hypoglycemia - low blood sugar (a blood glucose level <70>

• shakiness
• irritability
• lightheadedness
• rapid heart rate
• nervousness/anxiety
• excessive or abnormal sweating
• chills
• weakness
• tingling/numb sensation of the mouth and fingers
• headache
• hunger
• blurred vision
• confusion
• seizures
• unconsciousness

Active diabetics who are at a greater risk for experiencing exercise-induced hypoglycemia are those individuals who:

• Take insulin or medicine that lowers blood sugar levels (oral hypoglycemic medication)
• Exercise during the peak action time of their insulin dose
• Exercise for a prolonged period
• Exercise harder than usual
• Skip a meal or eat a meal that is too small
• Delay eating a meal
• Consume too few carbohydrates
• Have a cold or other illness
• Are under stress

Blood Sugar Monitoring - Know how your body's blood sugar level responds to physical activity. By checking your blood sugar level both before and after exercise you will be able to adjust your workouts accordingly. Your health care professional will provide you with a target value that is appropriate for you. Here are some general guidelines to follow:

• If you plan to exercise for an hour or more, consume an additional 15 grams of carbohydrate before or after exercise.
• If you intend to exercise vigorously, consume an additional 15-30 grams of carbohydrate (may need to be done every hour, discuss with your health care professional).
• If your pre-exercise blood sugar value is between 80-100 mg/dl, you are at risk for exercise-induced hypoglycemia. To prevent it, you should consume carbohydrates and wait for the value to increase before you begin exercising. A general rule-of-thumb to follow is the "15-15" protocol. That is, ingest 15 grams of carbohydrate and wait 15 minutes. Then retest your blood sugar. This procedure should be repeated until you reach your target number (as recommended by your health care professional).
• If your pre-exercise blood sugar level is at or above 300 mg/dl (or a fasting value above 250 mg/dl with ketones in urine for type I diabetics), exercise can cause the level to go even higher and, therefore, should be avoided until the value has been lowered.

Exercise Safety Precautions

• Wear your medical identification tag or carry your medical information card
• Exercise with a partner or in a medically supervised setting to protect yourself in the event of an emergency
• Carry a fast acting carbohydrate snack, such as life savers or graham crackers, with you while exercising in case you experience low blood sugar
• Drink plenty of water before, during, and after exercise
• Wear appropriate, well-cushioned footwear, especially if you have peripheral neuropathy
• If you are on insulin, inject it into your abdomen, not exercising limbs, to lower your risk for hypoglycemia
• To reduce the risk of nocturnal hypoglycemia, avoid exercising before bedtime (hypoglycemia can occur several hours after exercise). If you must exercise before bedtime, increase your consumption of carbohydrates.
• Exercising at the same time of day may reduce the likelihood of a hypoglycemic event
• Avoid vigorous exercise if you have retinopathy to reduce your risk for developing a detached retina

Know your own body and how to manage your symptoms when it comes to exercising with diabetes. To ensure your exercise program is safe and meets your needs, you should consult your health care professional to develop a routine that is appropriate for you. Make a copy of this article and take it along with you to your appointment to discuss issues of concern.

Note: Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources

American Diabetes Association

ACSM's Exercise Management for Persons with Chronic Diseases and Disabilities, 1997

ACSM's Guidelines for Exercise Testing and Prescription, Eighth Edition

     Aerobic exercise has long been considered the "power house" when it comes to yielding health benefits, especially in terms of modifying risk factors for cardiovascular disease.  However, resistance (strength) training is quickly climbing the ranks, proving it has a role in a comprehensive exercise regimen to promote better health.  Its positive effects on muscle strength, endurance, and power in the general healthy population have been well established.

     In the past, its safety for those at risk for or who have established cardiovascular disease has been questioned.  This mindset has changed in recent years.  Resistance training is now accepted by health professionals to be part of a well-rounded exercise program for this population.  Benefits include: enhanced muscular endurance and strength, improved capability of performing daily activities, promotion of independence, and increased self-confidence.  

     The effects of resistance training on obesity and diabetes, two risk factors for cardiovascular disease, has been less well understood.  A study that reviewed this area of interest was published in the March/April 2009 issue of the Journal of Cardiopulmonary Rehabilitation and Prevention.  Researchers obtained literature that was published during 1950-2008 from the MEDLINE Plus/Ovid literature search system to determine the effects of resistance training on obesity and diabetes.  Findings of the review substantiate the positive role that resistance exericse plays in the management of blood sugar and obesity.

Effects of Resistance Exercise on Blood Sugar Control

• Enhances insulin sensitivity
• Improves glucose tolerance 
  
• Decreases levels of glycated hemoglobin concentrations (high levels of glycated hemoglobin are associated with high blood pressure, heart disease, and kidney failure in individuals with metabolic syndrome and diabetes)
• Effects of resistance exercise appear to be related to changes in the trained muscle as opposed to an increase in muscle size 

Effects of Resistance Exercise on Obesity

• Improves overall body composition in both men and women
• Increases resting metabolic rate
• Decreases body fat, including abdominal and visceral fat (excess levels of these in particular have been associated with an increased risk for developing the metabolic syndrome)
• Increases muscle size and strength which leads to a greater tolerance for longer durations of aerobic exercise, thereby increasing the caloric expenditure of the activity 

     The researchers of the review conclude that resistance training appears to aid in the management of diabetes and obesity and, therefore, should be part of a comprehensive exercise program.  Resistance exercises do not have to be limited to the use of machines and/or dumbbells but can include resistance bands/tubing, medicine balls, and even soup cans or milk jugs.  The federal government's 2008 Physical Activity Guidelines for Americans recommends that apparently healthy adults and older adults perform moderate- to high- intensity muscle strengthening exercises for the major muscle groups of the body at least twice a week. 

Note:  Before beginning an exercise program or increasing the intensity level of a current routine, a physician's approval should be obtained, especially for older adults and those at risk for or who currently have chronic health conditions.

Resources

Journal of Cardiopulmonary Rehabilitation, vol 29(2), March/April 2009, pp. 67-75; "Resistance Training in the Treatment of Diabetes and Obesity:  Mechanisms and Outcomes," Tresierras, M., Balady, G.

2008 Physical Activity Guidelines for Americans (www.health.gov/paguidelines)

ACSM's Guidelines for Exercise Testing and Prescription, Eighth Edition