If you have diabetes or prediabetes, you may also have cardiovascular disease. Remember that about a third of all people with diabetes are not even aware of having it; sadly, many of them first learn of their condition while in the hospital after suffering their first heart attack, stroke, or other cardiovascular event. Does having heart disease mean that exercise is not for you? Absolutely not. Resistance training is now recommended for everyone, even people with known cardiovascular disease who have had a heart attack or stroke.
Diabetic people in supervised cardiac-rehabilitation exercise programs engage in various forms of exercise, and you may choose to join such a program if you know you have cardiovascular disease; you may also prefer to exercise on your own. It’s important to know that you’re more likely to experience angina (chest pain) due to reduced blood flow to your heart muscle (ischemia) during an aerobic activity like treadmill walking than during weight training. Studies have shown that lifting a heavy weight 10 to 12 times may increase your blood pressure more than aerobic work, but it doesn’t raise your heart rate as much. Ironically, the higher blood pressures reached during resistance training ensure that your heart muscle gets more blood than it would during aerobic activities. If you know that you have some coronary artery blockage from plaque buildup, moderate weight training may actually be a safer activity for you than most high-intensity aerobic ones.
If you prefer aerobic activities or if you do both types, use pain as your guide. In general, if reaching a certain heart rate (in number of beats per minute, or bpm) causes you to develop chest pain during exercise, always exercise at an intensity that keeps your rate at least 10 bpm below that pain threshold. For example, if slow jogging causes you to feel angina at a heart rate of 140 bpm, then lower your exercise intensity by walking briskly instead to keep your heart rate at 130 bpm or below at all times. In addition, be aware that a heart attack may have symptoms other than pain localized in your chest, such as pain that radiates down one arm or shoulder or your neck or that feels like bad heartburn. If you experience any unusual pain or other symptoms during or following exercise, get checked out by your doctor as soon as possible. Diabetes can also potentially cause you to experience silent ischemia, a reduction in blood flow to the heart muscle through the coronary blood vessels that is painless and symptom-free. If you experience a sudden, unexplained change in your ability to exercise, without any other symptoms, immediately stop exercising and consult with your physician as soon as you can to rule out silent ischemia.
In addition to improving diabetes-related health, regular aerobic exercise lessens the potential impact of most of the other cardiovascular risk factors, including elevated blood lipids (cholesterol and other blood fats), insulin resistance, obesity, and hypertension. Hypertension is associated with hyperinsulinemia, and regular physical activity can result in lower blood pressure and reduced circulating levels of insulin, making it very beneficial as far as your health is concerned.
If you have elevated blood pressure, though, it is best to avoid certain higher-intensity or heavy resistance exercises, which may cause your blood pressure to rise dangerously high and precipitate a stroke or other cardiovascular event. Activities best avoided include heavy weight training, near-maximal exercise of any type, activities that require intense, sustained contractions of the upper body, such as water-skiing or windsurfing, or any exercise for which you must hold your breath.
Finally, diabetes can cause a cardiovascular condition known as peripheral vascular disease (PVD), which reduces blood flow to your lower extremities. Some people with PVD have pain in their legs while walking or standing. If you experience these symptoms during or after physical activities and you have not yet been diagnosed with PVD, it would be best to confer with your physician to get a definite diagnosis before proceeding with your exercise program. If you do have blood-flow limitations to your lower legs and feet, you may have to choose activities that do not result in pain, such as seated exercises, water workouts, or stationary cycling.