Blood Sugar Fluctuations Throughout The Day
Metabolic Health
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Blood Sugar Fluctuations

When someone says that the life of a person with diabetes is like a roller coaster, they are not wrong. The roller coaster aspect of this would be on so many levels – 

  1. The time of the diagnosis – With a diabetes diagnosis comes a plethora of emotions and consequences. It would require a complete shift in how the daily life routine is and the person would have to make several short- and long-term changes in their life. 
  2. Sugar levels – If you ever happen to speak to a person with diabetes, they would tell you that sometimes, the most frustrating part of this condition would be that even though they do everything by the book, their sugar levels can still not come under control. This also comes with a roller coaster of not only the blood sugars but also the feelings associated with the highs and lows. 
  3. Decisions – A person with diabetes has a hard time making even simple decisions in their life as each choice that they make would have a chance of affecting their blood sugar levels. A small thing like where to eat dinner to a trip abroad for skydiving, all of these would have a different effect on the blood sugar levels and there would be 100 parameters to consider. This is another example of a roller coaster. 

At a more micro level, the roller coaster can also happen in their daily lives. Each day there can be a new pattern for how the blood sugar levels are in the body. Deciphering the pattern would be a futile task on many days. 

Blood Sugar level testing

Before you get accustomed to your body’s signs and signals, doctors recommend a pattern of testing blood sugar levels. This schedule given by the endocrinologist would help you identify lows and highs before it is too late and would also mitigate the range of fluctuations to make them less erratic. Catching the fluctuations early would be a helpful thing even in the long run as it would lead to lesser complications and a lower risk of poorer health conditions later. Here are different ways to be able to catch sugar fluctuations:

  1. Test pre and post-meals – Before and after every meal, take a reading on the glucometer. If you are going to do frequent checks, you can also consider a continuous glucose monitor
  2. Fasting – By regularly checking morning blood sugar levels, you will get an idea of how the levels are throughout the night. Higher levels in the morning would mean that you might be experiencing hypoglycemia at night. It could also mean that the basal during the night (or long-acting insulin) is not effective.
  3. Random sugars – One of the most effective ways to keep a lookout for fluctuations would be by checking the sugar levels at random times in the day. This will give a great insight into how well your insulin is working, whether you have the correct dose, and if your sugars are mainly in the optimal range. Read more about what level of blood sugar is dangerous.

Reason for Fluctuating Blood Sugar Levels

Your blood sugar levels might not follow a particular pattern and may fluctuate erratically due to several reasons:

  • Dehydration – If you have noticed a blood sugar 120 in the morning or have many high sugar levels when you check randomly, one potential reason could be dehydration. Lesser liquid and fluid in the body can result in a concentration in the sugar content. To make matters worse, this can also lead to frequent urination and further depletion of fluids. 
  • Dawn phenomenon – A high blood sugar reading can be due to this effect. Between 2 am to 8 am, the body releases sugar and cortisol to prepare to wake up. These hormones can make the body less sensitive to insulin and can lead to a spike in blood sugars. Eating a small snack at bedtime can prevent this
  • Menstrual cycles – Menses do not only lead to cramps, bloating, pimples, and mood swings but they can also lead to fluctuating blood sugar levels. It differs from woman to woman but a person with diabetes may become less sensitive to insulin a week before the period. The levels may come back to normal once the period starts. 
  • Insufficient sleep – Poor sleep can lead to low energy and motivation and can also hinder glucose sensitivity. Not getting enough sleep could be a sign of stress along with adding to the stress. Other common reasons for fluctuations in these levels are:
  • Diet
  • Physical activity
  • Medication (especially steroids)
  • Not taking the correct insulin dose
  • Illness or infections
  • Stress

Also read about benefits of dates for diabetes.

Symptoms of Fluctuating Blood Sugar Levels

When we check morning blood sugar levels or notice erratic blood sugar levels at any time of the day, they can have different symptoms based on the number that we see on the glucometer. Moreover, if you have a reading of 60 mg/dL in the afternoon today and the same reading the following afternoon, you may not always experience the same symptoms. Therefore, being aware of your sugar levels and noticing even minute changes in the body would be vital. Here are a few common symptoms one might experience during fluctuations:

  • Dizziness and feeling lightheaded
  • Weakness and lethargy
  • Irritability and mood swings
  • Anxiety
  • Dry skin and dry mouth
  • Shaking and trembling of hands
  • Palpitations and fast heartbeat
  • Headache
  • Increased urination and thirst
  • Double vision or blurred vision
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How to Control Fluctuating Blood Sugar Level?

If the reading is a blood sugar 120 in the morning or higher, and similar above-average readings are noted throughout the day, it would become important to control them promptly so that further complications are prevented. 

  1. Diet – Having a healthy diet plan with low carbs, low calories, and low sugar foods along with including protein-rich and fibrous foods in the meal chart would be ideal. Sticking to this diet routine will provide great results
  2. Carb counting – Along with having the right meals, knowing the number of carbs being consumed would help determine the level of insulin that needs to be taken. 
  3. Exercise – To control fluctuations, exercise is important as that can help to improve the overall metabolism and sensitivity to insulin
  4. Routine – If you have a fixed routine and your body knows what is about to come next, it would be better prepared. Also read about sugar level in urine

Treatment for Blood Sugar Level Fluctuations

Treatment and prevention of blood sugar fluctuations for a person with diabetes become a priority. The higher and more frequent the fluctuations, the more stress on different organs. Each person would experience fluctuations differently and therefore, how they are treated would also be different.

  1. Correction dose in case the sugars are high
  2. Glucose tablets or 15 grams of glucose in case the level is below 780 mg/dL
  3. Changing the insulin dose in case several highs or lows are happening at the same time every day
  4. Using a CGM to predict and prevent erratic fluctuations
  5. Visiting the doctor to identify patterns and check for any aspect that you might have missed that could be contributing to these fluctuation. Also read about uses and side effects of sugar tablet


While fluctuations in sugar levels are normal for a person with diabetes, very frequent and erratic ones might be a cause for concern. The damage that recurrent highs and lows can cause to different body parts might be irreparable if not treated early. For a person with diabetes, it becomes important to keep their HbA1c levels in check and schedule timely visits with their doctors to stay one step ahead of their diabetes-related symptoms. Also know about glucose fasting plasma.


Does the time of day affect Blood Sugar?

Most often than not, people notice a spike in their blood sugar levels in the morning between 2 am to 8 am. This is due to the Dawn phenomenon wherein the body releases certain hormones to prepare to wake up. This is why doctors recommend a 3 am testing of blood sugars on random days to assess the effect of the Dawn phenomenon. Also read about fasting blood sugar normal range.

What time of day is Blood Sugar highest?

While there is no definitive answer to this question as it might differ for everyone, very often a person might witness high blood sugars in the morning as a result of the Dawn effect of the Somogyi effect. However, sugars can also spike in an unprecedented manner in case they eat something with a lot of sugar. 

Does Blood Sugar rise after waking?

At times, the morning blood sugar levels can be higher than normal as the body releases cortisol and sugar in the middle of the night to provide it energy to wake up in the morning. 

Does drinking lots of water lower glucose?

Drinking a lot of water can dilute the level of sugar in the blood helping it come more under control. Also, water intake can lead to frequent urination which may be a good way to remove the toxins and ketones from the body, if any. Also know about plasma glucose.

Why is my Blood Sugar high in the evening?

Elevated blood sugars in the evening can happen due to a high carb snack, stress during the day, low dose of insulin during lunch, etc 




This website's content is provided only for educational reasons and is not meant to be a replacement for professional medical advice. Due to individual differences, the reader should contact their physician to decide whether the material is applicable to their case.