The dawn phenomenon

How in the world can your blood glucose climb during the night when you’re not eating a thing? Before blaming the carbs in last night’s dinner, consider these other common culprits

What’s affecting your BGLs at night

1 EARLY MORNING HORMONES

As you sleep, while your body is fasting, your liver is the primary driver of your blood glucose levels, says Gary Scheiner, certified diabetes educator and author of Think Like a Pancreas. All night long, the liver releases sugar to provide the brain and nervous system with energy. In the early hours of the morning, a series of hormones that boost energy and alertness send additional sugar into the blood to ready you for a new day. This rise from hormones is called the dawn phenomenon. But people with insulin resistance or too little insulin (or both) may have trouble dealing with this sugar surge, leading to high morning blood glucose levels, explains Scheiner.

POSSIBLE SOLUTIONS: Consider your medications. If you take insulin, you may need additional basal insulin at night to keep sugar stored in the liver when it’s not needed elsewhere. (Basal insulin covers your insulin needs around the clock, including while you sleep.) If you have type 2 and take medication other than insulin, you may need a greater dose of that med or an additional medication. Some drugs – such as metformin – reduce insulin resistance and also stop the liver releasing excess sugar.

2 A MISSED WORKOUT

Being physically active boosts insulin sensitivity, allowing your body to use insulin more efficiently for up to 48 hours post-workout. When you exercise regularly, your body naturally stays more sensitive to insulin, but if you miss your regular workout you might see a jump in your usual blood glucose levels. This can happen in the morning (but could also happen at any time of day).

POSSIBLE SOLUTIONS: Find an exercise routine that you like and can stick to. To avoid missed days, planning ahead can help: take a look at the week ahead to anticipate when you might miss a workout, and how you can still fit one in. Even carving out a few minutes to be active may help prevent you from waking up to high numbers.

3 1 NIGHT-TIME HYPOGLYCAEMIA

If your BGLs drop too low during the night, your body might crank out hormones such as adrenaline to counter that response, says Scheiner, who is also the founder and clinical director of Integrated Diabetes Services in Pennsylvania. This rebound, called the Somogyi effect, causes the liver to release more stored sugar, which raises blood glucose.

POSSIBLE SOLUTIONS: Monitor your blood sugar several times during the night – ideally using a continuous glucose monitor – to help identify if, and when, you experience hypoglycaemia. And be alert for common symptoms of night-time lows: sweating, nightmares and waking up with a headache. If you do experience hypoglycaemia, you may need a medication change such as less insulin or insulin secretagogue, a different type of medication or a change in dosing schedule. If you’re unable to adjust your prescriptions, a carb-containing snack at bedtime, such as yoghurt or a peanut butter sandwich, may do the trick.

4 DELAYED EFFECTS OF FATTY FOODS

Blood glucose levels typically peak within an hour or so after eating. However, a high-fat dinner containing fried foods, pizza or cheesy casseroles might delay this normal jump in blood glucose until the morning. Why? Large amounts of dietary fat can make it harder for insulin to do its job, explains Scheiner.

Plus, fat slows down digestion and absorption, which could cause your blood glucose to peak later than usual.

POSSIBLE SOLUTIONS: Opt for fish, skinless poultry, beans and vegetables sautéed in olive oil over foods high in saturated fat, such as fried foods and those covered in cheese. Filling up half your plate with vegetables can also help cut portion sizes of other foods – and your fat intake from those foods.