What is Overnight Glucose?

Overnight glucose in the Signos app is the average glucose level during your most stable 6-hour window overnight. It may be similar to fasting glucose, which is traditionally measured through a blood test after at least 8 hours without consuming calories. However, because Signos cannot confirm whether you were fasting during this window, we refer to it as overnight glucose rather than fasting glucose. 

Each point on your overnight glucose chart is an average of your last 30 days of overnight glucose.

What am I aiming for?

Aim for an average overnight glucose of 70–100 mg/dL (for healthy adults without Type 2 Diabetes).
For adults diagnosed with Type 2 Diabetes, aim for 80-130mg/dL initially, with a goal of gradually lowering this. 

It’s normal for your average to go up and down, so a single number doesn’t tell you much. Look at the overall trend and see whether there are nutrition and lifestyle changes that could help bring it down.

What can raise overnight glucose?

• Higher-carb or late dinners: Meal size, carbohydrate content, and timing may influence overnight glucose. Try to stop eating at least 3 hours before bed. Your hormones follow a circadian rhythm, and your body handles carbs less well at night.
• Poor sleep: Short or disrupted sleep is linked to poor glucose regulation. In studies of healthy young adults, repeated partial sleep loss led to decreased glucose tolerance and insulin sensitivity.
• Alcohol: If you drink in the evening, your glucose rise may be delayed, sometimes by several hours. Your body can’t store alcohol, so it breaks alcohol down first, before carbs, protein, and fat. This pushes the breakdown of carbs into glucose later into the night.
• Stress: Any stress response can raise glucose for some people, including nightmares.

What about early-morning rises?

If your glucose rises between about 4am and 8am, you’re likely seeing the Dawn Effect. In the early morning, your liver releases stored glucose into your bloodstream to give you fuel to wake up. The Dawn Effect can be a concern for people with diabetes, but it usually isn’t a problem for people without diabetes.

How should I interpret my data?

• Look at after-meal spikes first. Review all of your glucose data, with after-meal spikes as the priority. Suppose your overnight average trends higher and your spikes are also getting higher or have a larger area under the curve. Then it’s worth looking for changes that could help reduce those spikes.
• Focus on patterns, not exact numbers. Your body responds a little differently to each sensor, so different sensors can settle at different baselines. For example, one might sit around 85 and the next around 95. That’s not a cause for concern. Pay more attention to how your glucose responds to food, stress, sleep, and exercise than to the exact numbers.