- Drink 7 to 10 ounces of water 10 to 20 minutes before exercise.
- Drink 7 to 10 ounces of water every 10 to 20 minutes during activity.
- If you sweat heavily, you may need to drink more.
You should become familiar with the symptoms of heat illness. They are thirst, irritability, and general discomfort, followed by headache, weakness, dizziness, cramps, chills, vomiting, nausea, head or neck heat sensations, and decreased performance. Recognizing and treating dehydration early decreases the occurrence and severity of heat illness. Notice that some of these symptoms could be confused with hypoglycemia. Every effort should be made to stay hydrated, just as you would make every effort to avoid hypoglycemia.
Hypoglycemia. The greatest risk of exercise for people with diabetes is low blood sugar (hypoglycemia). Here are some simple measures you can take to assure your safety. If you have questions, consult your doctor or diabetes educator.
- Always check your blood sugar level before and after exercise and record the results. Your doctor or diabetes educator can help you adjust your insulin or snacks to account for any drop in blood sugar.
- Always have at least 15–30 grams of carbohydrate available to treat hypoglycemia (defined as blood sugar lower than 70 mg/dl). It’s best to keep more than 15 grams handy just in case you need more. Glucose tablets, raisins, and glucose gel will last for long periods of time in a backpack or fanny pack.
- If you suspect you are hypoglycemic, check your blood sugar level right away. If it is below 70 mg/dl, treat immediately with 15 grams of carbohydrate, rest for 15 minutes so that the snack can be absorbed, and then check again. If it is still below 70 mg/dl, have another 15 grams of carbohydrate. Fifteen grams of carbohydrate will raise your blood sugar approximately 30 mg/dl to 40 mg/dl in 10 to 15 minutes. Four ounces of juice, three 5-gram glucose tablets, one small box of raisins, or 4 ounces of regular soda (not diet), are a few examples of food servings containing 15 grams of carbohydrate.
- Certain medicines can mask the symptoms of hypoglycemia, so check with your doctor about any medicines you take.
- Exercise has some of the same symptoms of hypoglycemia (such as sweating and rapid heart rate). If you have hypoglycemia unawareness (inability to recognize hypoglycemic symptoms), be especially certain that you check your blood sugar level before and after exercise and are familiar with how your blood sugar responds to exercise.
- Exercise of long duration (longer than 30 minutes) or high intensity will cause blood sugar to drop more than shorter, less-intense exercise.
- Blood sugar tends to drop more during exercise in the afternoon or evening than it does in the morning.
- With guidance from your physician or diabetes educator, lower your preexercise insulin dose if you are sensitive to the effects of exercise. If you do not adjust your insulin before exercise, eat or drink 15 grams of carbohydrate for every 30 minutes of physical activity.
- Always carry money (preferably quarters) or a mobile phone in case you need to call for assistance, and always carry identification or wear a medical ID bracelet or necklace that says you have diabetes.
- If you have a sore throat, fever, or chest cold, postpone exercise until you feel better.
- Avoid exercise if your blood sugar is over 250 mg/dl and you have ketones in your blood or urine, and use caution when your blood sugar is over 300 mg/dl, even if no ketones are present.