Let’s take a deep dive into understanding blood sugar at bedtime and how this may impact your overall health goals
Checking blood sugar isn’t just for diabetics anymore. There’s a wealth of health information you can learn about your body from continuous glucose monitoring, and you can use this knowledge to help achieve your wellness goals.
As you begin monitoring your glucose around the clock, you’ll learn how certain foods, activities, and lifestyle choices affect your blood sugar. Once you get the hang of targeting optimal glucose ranges before and after meals, you might wonder what your ideal blood sugar should be before bed.
Non-diabetics should aim for a blood sugar range of 72–90 mg/dL or 4.0–5.0 mmol/L at bedtime for optimal health.
Non-pregnant adults with diabetes often target a blood sugar range of 80–130 mg/dL or 4.4–7.2 mmol/L. However, blood glucose targets should be individualized for those with diabetes.
Let’s take a deep dive into understanding blood sugar at bedtime and how this may impact your overall health goals.
Hyperglycemia, the technical term for elevated blood sugar, occurs when glucose levels are greater than 180 mg/dL.
For non-diabetics, average blood sugar ranges are:
For diabetics, average blood sugar ranges are:
If your blood sugar readings at bedtime are higher than your goal, consider whether one or more of the following factors could be the cause.
Glucose readings may fluctuate depending on the amount of time that has passed since your last meal. If you experience high blood sugar at night, one of the first things to consider is how long it’s been since you last ate.
A small study conducted on healthy men and women observed participants wearing continuous glucose monitors for almost three days and provided dinner to one group at 6 p.m. and the other at 9 p.m. Only data from the mornings of days 2 and 3 were used for analysis, and results showed a significant decrease in postprandial respiratory quotient after breakfast on day 3 in the early dinner group. Researchers concluded that eating an earlier dinner had a positive impact on blood glucose fluctuation<sup>1</sup> and metabolism.
Meals full of both fat and carbohydrates may require a longer time for digestion, resulting in higher glucose readings several hours after eating.
One study with young, healthy participants showed that eating a late dinner composed of 50% carbs, 35% fat, and 35% of total daily calories caused a prolonged glucose intolerance and reduced fatty acid oxidation<sup>2</sup> during sleep—particularly in those who hit the hay earlier—and an increase in cortisol. Researchers hypothesized that these same metabolic reactions could contribute to obesity if repeated consistently.
Steroids such as hydrocortisone, dexamethasone, and prednisone are often used to control inflammation, manage asthma flare-ups, or suppress autoimmune reactions. However, these medications also can cause a dramatic increase in blood sugar.
Even non-diabetics may experience steep spikes in blood sugar<sup>3</sup> while taking steroids, and long-term treatment may increase a person’s chance of developing diabetes.
However, inhaled steroids for asthma and topical formulations such as creams and ointments won’t affect your blood sugar.
Some medications used for depression, anxiety, ADHD, birth control, high cholesterol, or high blood pressure also can increase blood glucose levels.
Alcoholic beverages contain carbohydrates and are often high in calories, which can wreak havoc on your blood sugar control. Alcohol also stimulates your appetite<sup>4</sup>, which can prompt you to eat more, making it more difficult to stay within the ideal glucose range.
What’s more, the body prioritizes alcohol metabolism first, so any food you might eat with that glass of wine, beer, or spirit gets processed after the alcohol. This can lead to more prolonged or delayed glucose responses to the food you eat while drinking.
Believe it or not, stress can be a huge factor that affects your blood sugar. During times of emotional hardship, your body releases stress hormones, such as cortisol, which prompts an increase in glucose even if you haven’t eaten.
Much like emotional stress, sickness can impose physical stress on your body. Whether it’s a cold, the flu, or something more serious, your body responds to illness by releasing glucose<sup>5</sup>. When you’re sick, you may be surprised to have high blood sugar even if you haven’t had normal food intake.
It may be obvious that sweet drinks like soda and juice will spike your blood sugar, but consuming sugary beverages can be a hard habit to break. Many people opt for artificially sweetened beverages in place of the real deal.
However, a review of current research suggests that artificially-sweetened drinks may affect glycemic control<sup>6</sup> (albeit indirectly). Artificial sweeteners may also alter your gut microbiota; one study examined in the review demonstrated that artificial sweeteners induce glucose intolerance in mice and human subsets. More research is needed to fully understand the role of artificial sweeteners in managing blood sugar.
Good old-fashioned water is always the best choice for hydration and health.
With less water in your bloodstream, glucose becomes more concentrated. Drinking adequate amounts of water is crucial for optimal blood sugar control.
We discussed previously that stress hormones affect blood sugar, but hormonal changes that occur in the premenstrual phase of a woman’s monthly cycle may play a role<sup>7</sup>, too. More research is needed to fully understand this phenomenon.
It is well-documented that poor sleep has wide-ranging effects on the way our bodies process glucose. Sleep problems are linked not only to high blood sugar<sup>8</sup>, but also insulin resistance, type 2 diabetes, metabolic syndrome, and obesity.
The dawn effect, sometimes called the dawn phenomenon, is when your body naturally releases a surge of glucose into your bloodstream in the early hours of the morning. It usually takes place sometime between 3 a.m. and 8 a.m.
Non-diabetics may see this increase in glucose, but the body will release insulin to bring blood sugar back to normal.
Diabetics may struggle to control their blood sugar in the morning since their bodies have difficulty producing or using insulin to manage the glucose surge.
People with diabetes may have some of these symptoms<sup>9</sup> when their blood sugar is high:
However, if you don’t have diabetes, you likely will not experience symptoms related to high blood sugar. Why? Because your body manages glucose appropriately. You won’t have the same symptoms as a diabetic who struggles to manage the excess glucose.
If you’re using the Signos app, you’ll receive an alert to let you know when your glucose is out of range. If your glucose is high, consider exercising for at least 10 minutes to lower your levels.
Here are a few ideas:
Hypoglycemia, or low blood sugar, is defined as a glucose reading less than 70 mg/dL.
People with diabetes must manage their blood sugar and their medication regimen carefully to avoid hypoglycemia.
However, if you do not have diabetes, it is unlikely you’ll experience sustained hypoglycemia resulting in troublesome symptoms.
Some people experience what is known as nocturnal hypoglycemia when glucose dips during sleep. This happens to people with diabetes if they eat too little in the evening or give themselves too much insulin. In addition, diabetics may experience low blood sugar if they exercise too much without supplementing their food intake.
Here are some more variables that can contribute to low blood sugar:
However, a review published in The Journal of Clinical Endocrinology & Metabolism showed that other medications may contribute to low blood sugar<sup>10</sup> as well, such as:
That said, researchers noted that very low-quality evidence backs up the association between low blood sugar and the use of non-diabetic drugs.
While popular heart and blood pressure medications such as beta-blockers and ACE-inhibitors have been linked with episodes of low blood sugar<sup>11</sup> as well, more research is needed to determine whether these medications cause low blood sugar.
If you don’t have diabetes but have ongoing trouble with low blood sugar, you should talk to your doctor. Serious problems such as liver disease, autoimmune disease, kidney problems, and certain tumors can cause low blood sugar, so seek medical help to determine the underlying cause.
Here are some of the signs associated with low blood sugar:
If your blood sugar is below your target range at bedtime, try eating a small, healthy snack such as:
If your blood sugar is bouncing all over the place at night, try these simple changes to your evening routine.
As you implement these tips for managing your glucose, keep in mind that it’s a process. Continuous glucose monitoring will allow you to get to know your body better with time, and you’ll begin to understand exactly what your body needs.
And remember—strive for progress, not perfection.