Diabetes management takes awareness. Know what makes your blood sugar level rise and fall — and how to control these day-to-day factors.

By Mayo Clinic Staff

When you have diabetes, it's important to keep your blood sugar levels within the range recommended by your healthcare professional. But many things can make your blood sugar levels change, sometimes quickly. Find out some of the factors that can affect blood sugar. Then learn what you can do to manage them.

Healthy eating is important for everyone. But when you have diabetes, you need to know how foods affect your blood sugar levels. It's not only the type of food you eat. It's also how much you eat and the types of food you combine in meals and snacks.

What to do:

  • Learn about planning balanced meals. A healthy-eating plan includes knowing what to eat and how much to eat. Two common ways to plan meals are carbohydrate counting and the plate method. Ask your healthcare professional or a registered dietitian if either type of meal planning is right for you.

  • Understand carbohydrate counting. Counting carbs involves keeping track of how many grams of carbohydrates you eat and drink during the day. If you take diabetes medicine called insulin at mealtimes, it's important to know the amount of carbohydrates in foods and drinks. That way, you can take the right dose of insulin.

    Among all foods, carbs often have the biggest impact on blood sugar levels. That's because the body breaks them down into sugar, which raises blood sugar levels. Some carbs are better for you than others. For example, fruits, vegetables and whole grains are full of nutrients. They have fiber that helps keep blood sugar levels more stable too. Eat fewer refined, highly processed carbs. These include white bread, white rice, sugary cereal, cakes, cookies, candy and chips.

  • Get to know the plate method. This type of meal planning is simpler than counting carbs. The plate method helps you eat a healthy balance of foods and control portion sizes.

    Use a 9-inch plate. Fill half of the plate with nonstarchy vegetables. Examples include lettuce, cucumbers, broccoli, tomatoes and green beans. Divide the other half of the plate into two smaller, equal sections. You might hear these smaller sections called quarters. In one quarter of the plate, place a lean protein. Examples include fish, beans, eggs, and lean meat and poultry. On the other quarter, place healthy carbohydrates such as fruits and whole grains.

  • Be mindful of portion sizes. Learn what portion size is right for each type of food. Everyday objects can help you remember. For example, one serving of meat or poultry is about the size of a deck of cards. A serving of cheese is about the size of six grapes. And a serving of cooked pasta or rice is about the size of a fist. You also can use measuring cups or a scale to help make sure you get the right portion sizes.

  • Balance your meals and medicines. If you take diabetes medicine, it's important to balance what you eat and drink with your medicine. Too little food in proportion to your diabetes medicine — especially insulin — can lead to dangerously low blood sugar. This is called hypoglycemia. Too much food may cause your blood sugar level to climb too high. This is called hyperglycemia. Talk to your diabetes health care team about how to best coordinate meal and medicine schedules.

  • Limit sugary drinks. Sugar-sweetened drinks tend to be high in calories and low in nutrition. They also cause blood sugar to rise quickly. So it's best to limit these types of drinks if you have diabetes. The exception is if you have a low blood sugar level. Sugary drinks can be used to quickly raise blood sugar that is too low. These drinks include regular soda, juice and sports drinks.

Exercise is another important part of managing diabetes. When you move and get active, your muscles use blood sugar for energy. Regular physical activity also helps your body use insulin better.

These factors work together to lower your blood sugar level. The more strenuous your workout, the longer the effect lasts. But even light activities can improve your blood sugar level. Light activities include housework, gardening and walking.

What to do:

  • Talk to your healthcare professional about an exercise plan. Ask your healthcare professional what type of exercise is right for you. In general, most adults should get at least 150 minutes a week of moderate aerobic activity. That includes activities that get the heart pumping, such as walking, biking and swimming. Aim for about 30 minutes of moderate aerobic activity a day on most days of the week. Most adults also should aim to do strength-building exercise 2 to 3 times a week.

    If you haven't been active for a long time, your healthcare professional may want to check your overall health first. Then the right balance of aerobic and muscle-strengthening exercise can be recommended.

  • Keep an exercise schedule. Ask your healthcare professional about the best time of day for you to exercise. That way, your workout routine is aligned with your meal and medicine schedules.

  • Know your numbers. Talk with your healthcare professional about what blood sugar levels are right for you before you start exercise.

  • Check your blood sugar level. Also talk with your healthcare professional about your blood sugar testing needs. If you don't take insulin or other diabetes medicines, you likely won't need to check your blood sugar before or during exercise.

    But if you take insulin or other diabetes medicines, testing is important. Check your blood sugar before, during and after exercise. Many diabetes medicines lower blood sugar. So does exercise, and its effects can last up to a day later. The risk of low blood sugar is greater if the activity is new to you. The risk also is greater if you start to exercise at a more intense level. Be aware of symptoms of low blood sugar. These include feeling shaky, weak, tired, hungry, lightheaded, irritable, anxious or confused.

  • See if you need a snack. Have a small snack before you exercise if you use insulin and your blood sugar level is low. A blood sugar level below 90 milligrams per deciliter (mg/dL), which is 5.0 millimoles per liter (mmol/L), is too low. The snack you have before exercise should contain about 15 to 30 grams of carbs. Or you could take 10 to 20 grams of glucose products. This helps prevent a low blood sugar level. If your blood sugar is 90 to 124 mg/dL (5.0 to 6.9 mmol/L), have 10 grams of glucose before you exercise.

  • Stay hydrated. Drink plenty of water or other fluids while exercising. Dehydration can affect blood sugar levels.

  • Be prepared. Always have a small snack, glucose tablets or glucose gel with you during exercise. You'll need a quick way to boost your blood sugar if it drops too low. Carry medical identification too. In case of an emergency, medical identification can show others that you have diabetes. It also can show whether you take diabetes medicine such as insulin. Medical IDs come in forms such as cards, bracelets and necklaces.

  • Adjust your diabetes treatment plan as needed. If you take insulin, you may need to lower your insulin dose before you exercise. You also may need to watch your blood sugar level closely for several hours after intense activity. That's because low blood sugar can happen later on. Your healthcare professional can advise you how to correctly make changes to your medicine. You also may need to adjust your treatment if you've increased how often or how hard you exercise.

Insulin and other diabetes medicines are designed to lower blood sugar levels when diet and exercise alone don't help enough. How well these medicines work depends on the timing and size of the dose. Medicines you take for conditions other than diabetes also can affect your blood sugar levels.

What to do:

  • Store insulin properly. Insulin that is not stored properly or is past its expiration date may not work. Keep insulin away from extreme heat or cold. Don't store it in the freezer or in direct sunlight.

  • Tell your healthcare professional about any medicine problems. If your diabetes medicines cause your blood sugar level to drop too low, the dosage or timing may need to be changed. Your healthcare professional also might adjust your medicine if your blood sugar stays too high.

  • Be cautious with new medicines. Talk with your healthcare team or pharmacist before you try new medicines. That includes medicines sold without a prescription and those prescribed for other medical conditions. Ask how the new medicine might affect your blood sugar levels and any diabetes medicines you take. Sometimes a different medicine may be used to prevent dangerous side effects. Or a different medicine might be used to prevent your current medicine from mixing poorly with a new one.

With diabetes, it's important to be prepared for times of illness. When you're sick, your body makes stress-related hormones that help fight the illness. But those hormones also can raise your blood sugar. Changes in your appetite and usual activity also may affect your blood sugar level.

What to do:

  • Plan ahead. Work with your healthcare team to make a plan for sick days. Include instructions on what medicines to take and how to adjust your medicines if needed. Also note how often to measure your blood sugar. Ask your healthcare professional if you need to measure levels of acids in the urine called ketones. Your plan also should include what foods and drinks to have, and what cold or flu medicines you can take. Know when to call your healthcare professional too. For example, it's important to call if you run a fever over 101 degrees Fahrenheit (38.3 degrees Celsius) for 24 hours.

  • Keep taking your diabetes medicine. But call your healthcare professional if you can't eat because of an upset stomach or vomiting. In these situations, you may need to change your insulin dose. If you take rapid-acting or short-acting insulin or other diabetes medicine, you may need to lower the dose or stop taking it for a time. These medicines need to be carefully balanced with food to prevent low blood sugar. But if you use long-acting insulin, do not stop taking it. During times of illness, it's also important to check your blood sugar often.

  • Stick to your diabetes meal plan if you can. Eating as usual helps you control your blood sugar. Keep a supply of foods that are easy on your stomach. These include gelatin, crackers, soups, instant pudding and applesauce.

    Drink lots of water or other fluids that don't add calories, such as tea, to make sure you stay hydrated. If you take insulin, you may need to sip sugary drinks such as juice or sports drinks. These drinks can help keep your blood sugar from dropping too low.

It's risky for some people with diabetes to drink alcohol. Alcohol can lead to low blood sugar shortly after you drink it and for hours afterward. The liver usually releases stored sugar to offset falling blood sugar levels. But if your liver is processing alcohol, it may not give your blood sugar the needed boost.

What to do:

  • Get your healthcare professional's OK to drink alcohol. With diabetes, drinking too much alcohol sometimes can lead to health conditions such as nerve damage. But if your diabetes is under control and your healthcare professional agrees, an occasional alcoholic drink is fine.

    Women should have no more than one drink a day. Men should have no more than two drinks a day. One drink equals a 12-ounce beer, 5 ounces of wine or 1.5 ounces of distilled spirits.

  • Don't drink alcohol on an empty stomach. If you take insulin or other diabetes medicines, eat before you drink alcohol. This helps prevent low blood sugar. Or drink alcohol with a meal.

  • Choose your drinks carefully. Light beer and dry wines have fewer calories and carbohydrates than do other alcoholic drinks. If you prefer mixed drinks, sugar-free mixers won't raise your blood sugar. Some examples of sugar-free mixers are diet soda, diet tonic, club soda and seltzer.

  • Add up calories from alcohol. If you count calories, include the calories from any alcohol you drink in your daily count. Ask your healthcare professional or a registered dietitian how to make calories and carbohydrates from alcoholic drinks part of your diet plan.

  • Check your blood sugar level before bed. Alcohol can lower blood sugar levels long after you've had your last drink. So check your blood sugar level before you go to sleep. If your blood sugar isn't between 100 mg/dL and 140 mg/dL (5.6 mm/L and 7.8 mmol/L), have a snack before bed. The snack can counter a drop in your blood sugar.

Periods and menopause both have important effects for people with diabetes.

Changes in hormone levels the week before and during periods can lead to swings in blood sugar levels.

What to do:

  • Look for patterns. Keep careful track of your blood sugar readings from month to month. You may be able to predict blood sugar changes related to your menstrual cycle.

  • Adjust your diabetes treatment plan as needed. Your healthcare professional may recommend changes in your meal plan, activity level or diabetes medicines. These changes can make up for blood sugar swings.

  • Check blood sugar more often. If you're likely nearing menopause or if you're in menopause, talk with your healthcare professional. Ask whether you need to check your blood sugar more often. Also, be aware that menopause and low blood sugar have some symptoms in common, such as sweating and mood changes. So whenever you can, check your blood sugar before you treat your symptoms. That way you can confirm whether your blood sugar is low.

Most types of birth control are safe to use when you have diabetes. But combination birth control pills may raise blood sugar levels in some people.

It's very important to take charge of stress when you have diabetes. The hormones your body makes in response to prolonged stress may cause your blood sugar to rise. It also may be harder to closely follow your usual routine to manage diabetes if you're under a lot of extra pressure.

What to do:

  • Take control. Once you know how stress affects your blood sugar level, make healthy changes. Learn relaxation techniques, rank tasks in order of importance and set limits. Whenever you can, stay away from things that cause stress for you. Exercise often to help relieve stress and lower your blood sugar.

  • Get help. Learn new ways to manage stress. You may find that working with a psychologist or clinical social worker can help. These professionals can help you notice stressors, solve stressful problems and learn coping skills.

The more you know about factors that have an effect on your blood sugar level, the better you can prepare to manage diabetes. If you have trouble keeping your blood sugar in your target range, ask your diabetes healthcare team for help.

Jan. 06, 2024