Morning highs can be confusing. After all, you haven't slept in the past nine hours, in other words, you haven't eaten any carbs. What is happening?
What Causes High Blood Sugar in the Morning?
Two major culprits give rise to morning highs: the dawn phenomenon and declining insulin. A third, much rarer cause, known as the Somogyi effect, may also be to blame.
The occasional high morning has little impact on your A1C, a measure of your average blood sugar (blood sugar) over time that indicates how well your diabetes is being managed. But if these highs become consistent, they can push your A1C into dangerous territory.
The dawn phenomenon
In the early morning hours, hormones, including cortisol and growth hormone, signal the liver to increase the production of glucose, which provides energy that helps you wake up. This triggers beta cells in the pancreas to release insulin to control blood sugar levels. But if you have diabetes, you may not make enough insulin or be too insulin resistant to counteract the rise in blood sugar. As a result, your levels may be elevated when you wake up. The dawn phenomenon does not distinguish between types of diabetes. About half of those with type 1 or type 2 experience it.
Falling insulin
If your insulin level drops too low at night, your blood sugar levels rise. The reasons for the drop in insulin vary from person to person, but it usually happens when your insulin pump settings don't deliver enough basal (background) insulin at night, or your long-acting insulin dose is too low. Insulin duration -- how long the drug works in your body -- also plays a role. If you inject your long-acting insulin early, it may not last until the morning.
The Somogyi effect
Named after Michael Somogyi, PhD, a chemist who first described it in the 1930s, the Somogyi effect is the body's response to low blood sugar (hypoglycemia) during the night. Let's say you skip dinner or take too much insulin after your evening meal. Your blood sugar can drop too low overnight. Your body produces more glucose to compensate and you wake up with high blood sugar.
So what can you do?
Collect the tracks
If a pattern of frequent morning highs occurs during your routine glucose monitoring, check your blood glucose levels before bed, in the middle of the night, and first upon waking to develop a better understanding of your glucose patterns. If you use a continuous glucose monitor (CGM), you can sleep through the night and it collects the data you need. If you don't use one, see if your doctor can give you a temporary loan.
Identify the culprit
Your readings will tell you and your doctor when your highs and lows are occurring, which in turn will help narrow down the source of the problem.
If the data shows you are high before bed, the culprits are likely food and drugs.
If you have high blood sugar before going to bed, the elevated level can last into the morning. A big snack before dinner or before bed can cause an increase in blood sugar that lasts through the night, as can too little insulin with your evening meal. It may help to adjust your medication or what and when you eat.
If the data shows that you're within range before bed, the culprit is likely under-medication.
You can go to bed with blood sugar levels within your target range, but that doesn't mean they stay that way overnight. If you e.g. If you take a long-acting insulin in the morning and it wears off before you take the next dose the next day, you will see an increase in blood sugar in the morning. The problem can be solved by changing the time of your long-acting insulin injection or switching to twice daily basal insulin or an ultra-long-acting insulin.
If the data shows that you are noisy in the wee hours, the culprit is likely the dawn phenomenon.
If you experience the dawn phenomenon, which causes your blood sugar to spike between about 3 and 8 a.m., your doctor may recommend that you don't increase your long-acting insulin. While a higher dose of insulin will return your morning highs to normal, it can cause your blood sugar to drop too much after you first go to bed, but before your blood sugar starts to rise in the early morning hours. Sometimes the only way to cope with dawn is to use an insulin pump that you can program to automatically deliver more insulin in the wee hours of the morning.
If you don't take insulin, it can take quite a bit of trial and error before you and your healthcare provider find the best medication and lifestyle strategy to help reduce morning sickness.
Find out
Exercise can also help you manage your morning highs. If you're on tapering insulin, taking a walk after dinner or other exercise can help keep your blood sugar low at night. But be careful when exercising before bed. The blood sugar-lowering effects of exercise can last for hours, so exercising before bed puts you at risk of getting low at night.
Morning exercise may be best if your blood glucose data has shown a tendency for nighttime lows after late afternoon or evening exercise. Breaking a sweat in the morning is also a good idea for anyone who suffers from the break of dawn - it can help burn off the extra blood sugar.
Try it, try again
There is no single recipe for managing morning highs. What works for one person may not work for you. It can take some time to figure out the best strategy to keep your blood sugar at the right level in the morning and avoid hypoglycemia at night. In rare cases, the ideal balance cannot be found. For these people, their doctors may raise their morning blood sugar target slightly higher, as long as it stays within the target range for the rest of the day. But most people will be able to figure out what's going on and what they need to adjust.
