Are your blood glucose levels high right before you go to bed? One of the benefits of using a CGM for non-diabetics is that you'll be able to identify these spikes and determine what's causing them.
Whether or not you have diabetes, it's possible to have high glucose levels in the evening. This can cause restless and poor-quality sleep as we discussed in our glucose and sleep article. Having optimal glucose values during the night and while sleeping will help you feel better and perform better the next day.
Generally, you want to aim for glucose values around 70-100 mg/dL before bed and while you are sleeping. This range of values sets you up to hit a target of 70-90 mg/dL upon waking, which research indicates is an ideal range for fasting glucose levels
Why is my blood glucose high right before I go to bed?
If your evening glucose levels are outside the 70-100 mg/dL range, there are several areas you can troubleshoot. Some of these include:
Eating right before bed
Many of our metabolic hormones, such as insulin, work on a circadian rhythm. Most people notice they can eat the same exact meal in the middle of the day and have a drastically lower glucose response than if that same meal is consumed late at night.
In 2019, the journal MDPI published a fascinating study demonstrating the bidirectional nature between food intake and circadian rhythm. Participants were divided into two groups: one ate all their calories between 8am-2pm, and the other consumed their calories between 8am-8pm. The result was the early time restricted feeding (eTRF) group decreased mean glucose levels & glycemic excursions and positively altered the expression of several circadian clock genes.
In other words, participants saw health improvements simply by changing when they ate rather than changing what they ate.
Consuming a high carbohydrate + high fat meal
When you consume food that is high carbohydrate and high fat (think pizza, fried food, creamy pasta, donuts), the fat slows down digestion, causing glucose to be released into the bloodstream over a long period of time. This often results in elevated glucose values for 5 or more hours.
Stuart Chipkin, one of the lead authors of the study “Continuous Glucose Monitoring in Non–Insulin-Using Individuals with Type 2 Diabetes”, demonstrates this phenomenon via CGM (continuous glucose monitor) data.
The study participants experienced hour after hour of abnormally high glucose levels due to the high fat + high carb food combinations in their diet.
Lack of movement during the day
You might be aware that insulin is responsible for pushing glucose into muscle cells for storage, which is called insulin-mediated glucose uptake. But glucose can also be stored in your muscle cells through simple mechanical contraction in a process called non-insulin-mediated glucose uptake.
Even gentle movement such as leisurely walking can significantly lower glucose values. Our skeletal muscles take up 80% of our circulating glucose values, so any type of movement helps to stabilize glucose levels.
High stress levels
When your body senses a stressful situation, it causes a release of hormones like cortisol and adrenaline that tell the body: “Produce energy NOW.” Part of this signal stimulates the liver to create and release new glucose into the bloodstream so that energy is readily available to fuel muscular activity.
In the context of acute stress in an ancestral environment, this system works great. You see a predator, you get super-charged with stress hormones & glucose, you sprint for your life, and (if you escape) then your brain sends a signal to slow back down, and everything returns to normal.
The problem in today’s world, however, is many people never get the signal to “slow back down”. Instead of acute stress, most people live with chronic stress, which can cause the stress response to occur at low levels all the time. When that happens, it can cause your glucose values to become pathologically high.
Check out our article on managing stress and biohacking the cortisol response for additional strategies regarding stress management.
If you are sick with an infection or the flu, systemic inflammation may lead to impairment of the insulin receptor at the level of the muscle.
When this scenario was tested in the lab on healthy mice, glucose response remained normal. However, when the same infection was given to pre-diabetic mice, the mice developed glucose intolerance.
Given that over 88% of Americans have some form of metabolic syndrome, the odds are high that an illness might lead to higher glucose values.
When we become dehydrated, the body releases a hormone called vasopressin which helps to retain water. Vasopressin can also stimulate the liver to produce glucose, causing our blood glucose values to rise.
How to prevent high blood glucose before bed?
Each of the factors above lend themselves to simple strategies for reducing glucose levels in the evening. If your levels are high, then try or more of these tactics:
Try to avoid food at least 3 hours before bed
For most people we work with, 3 hours of fasting before bed helps to even out nighttime glucose values. If it has calories, then don’t eat or drink it. Simple as that!
However, if your schedule makes it difficult to avoid food within 3 hours of sleep, there are still strategies available to minimize high glucose values before bed, such as…
Aim for lower carbohydrate dinners
Try to make your evening meal mostly protein + fiber from non-starchy vegetables and keep your total carbohydrate intake at this meal lower (especially if you are not able to avoid a late-night dinner). Since we naturally have decreased insulin sensitivity at night, lowering the carbohydrate content in this meal can help to compensate.
Here are a few examples of what a higher protein + fiber meal could look like from the website DietPlan-101.
Another benefit of foods higher in protein and lower in refined carbohydrates is they tend to be very satiating. Dr. Ted Naiman, author of The P:E Diet, demonstrates this point by comparing two isocaloric foods: Salmon and a donut.
Both food items are 300 calories, but the metabolic effect in the body is completely different.
- The salmon is high in protein, fat (including Omega-3s), and fat-soluble vitamins and minerals. The effect on glucose values is negligible.
- On the other hand, the donut is high in refined carbohydrates & vegetable oils and is devoid of protein or vitamins/minerals. A donut is a prime example of a food that spikes glucose both acutely and over the following several hours.
All calories are not created equal. The composition of your meal matters.
Go on a casual walk after dinner
We have seen that even a 15-minute walk after a meal can help to lower glucose levels. Not surprisingly, research also shows that a higher step count is independently associated with greater insulin sensitivity.
A casual walk after dinner is a great way to stack multiple benefits into one activity. For example, doing your walk with a friend or loved one can improve feelings of social connectedness, which in turn reduces psychological stress. Lower levels of stress reduce the production of compounds like cortisol and epinephrine (adrenaline), which correspondingly lowers glucose values. Win-win!
Destress before bed
Engage in a consistent evening routine that helps to unwind and destress you. We create a bedtime routine for our children, and we should do the same for ourselves. This looks different for everyone, but it might include reading, taking a bath, or journaling.
Stay hydrated throughout the day
Aim to consume enough water and sugar-free liquids throughout the day. “Enough” varies from person to person and greatly depends on your lifestyle (activity levels, nutrient intake, geographic location, seasonality, and more).
The best way to monitor hydration status is to make sure your urine is a light color.
What if my blood glucose is low before I go to bed?
Many non-diabetics will have glucose values below 70 mg/dL without any symptoms of hypoglycemia (dizziness, shaking, etc.). If no symptoms are present and glucose is above 55 mg/dL, then there is nothing to be concerned about.
But if you are curious about your low glucose values, then there are a few avenues you can inspect:
Many people see a glucose dip several hours after drinking alcohol because the body prioritizes metabolizing alcohol over other functions (since alcohol is technically a toxin). Studies suggest that alcohol temporarily impairs the normal functions in the liver that moderate normal glucose levels, such as the balance of insulin and glucagon. It also appears to temporarily interfere with liver gluconeogenesis (making more glucose) and glycogenolysis (breaking down stored glucose).
If you consume a highly sugary item before bed, it can cause what is called “reactive hypoglycemia”.
If you eat too much sugar or starch, then it can lead to a significant glucose spike. In some situations, your pancreas can overcompensate and pump out too much insulin in response. This causes blood sugar to fall below healthy levels and can produce symptoms of low blood sugar like dizziness, shaking, weakness, or anxiety.
Some medications may cause hypoglycemia in non-diabetics. Medications to monitor include:
- Antibiotics (quinine, bactrim, gatifloxacin, pentamidine, fluoroquinolones)
- Beta blockers
- Bile Acid Sequestrants (Welchol)
How to prevent low blood glucose before bedtime?
Based on the topics discussed above, there are several strategies you can explore to help “even out” your low glucose levels in the evening:
Monitor alcohol intake
Try to avoid alcohol right before bedtime and consume moderate amounts if you are drinking alcohol (1-2 servings).
A “serving” of alcohol is described by the Mayo Clinic as 12 fl ounces of beer, 1.5 fl ounces of liquor, or 5 fl ounces of wine.
Avoid sweets right before bed
We have discussed how insulin sensitivity decreases in the evening, as well as the potential reactive hypoglycemic effects of high sugar/starch foods. Avoiding sweets before bed can help circumvent both of those issues.
If you still find yourself craving something sweet, try switching to sources that include fiber (like fruit) or have a reduced sugar content (like dark chocolate). This can aid in smoothing out glucose levels.
Talk to your MD about potential medication interactions
If you suspect one of your medications may be giving you low glucose levels, then talk to your doctor about potential solutions. Drug interactions can be highly nuanced and are not something to experiment with in a haphazard way.
Engage with Your Blood Glucose Levels with Nutrisense
Your blood sugar levels can significantly impact how your body feels and functions. That’s why stable blood glucose levels can be an important factor in supporting overall wellbeing.
With Nutrisense, you’ll be able to track your blood glucose levels over time using a CGM, so you can make lifestyle choices that support healthy living.
Ready to take the first step? Start with our quiz to see how Nutrisense can support your health.
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Kara Collier is the co-founder and VP of Health at Nutrisense, one of America’s fastest-growing wellness-tech startups, where she leads the health team. She is a Forbes 30 under 30 recipient, frequent podcast guest & conference speaker.