People living with diabetes need to manage their levels of blood sugar, or glucose. Monitoring glucose levels, regularly exercising, and following a diet plan with a doctor’s approval can help people keep sugar levels in their target range.

High blood sugar levels, known as hyperglycemia, occur when a person’s blood sugar is over 180 milligrams per deciliter (mg/dL). People with diabetes to control their blood sugar levels and keep them within the target range as their doctor has specified.

Without prompt management, hyperglycemia can lead to short-term and long-term complications.

Strategies to achieve this include monitoring blood sugar, limiting the intake of carbohydrates, and maintaining a moderate weight.

In this article, we look at different ways to lower high blood sugar levels. We also explain why it is important to do this and how long it takes.

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High blood sugar typically refers to levels over 180 mg/dL. However, a person may not experience diabetes symptoms until the levels exceed 200 mg/dL. As such, it is essential for a person with diabetes to check their blood sugar several times a day. Doing so should mean that blood sugar levels never get excessively high.

A person with diabetes can use an at-home glucose monitor to check their blood sugar levels. One option is a continuous glucose monitor, which is a medical device that easily enables someone to check their blood sugar levels.

The recommended number of times to check glucose levels during the day will vary from person to person. A doctor can make the best recommendations regarding the testing frequency.

A low carb diet limits the amount of carbohydrates a person consumes. Carbs raise blood glucose more than other foods, and evidence suggests that a low carb dietary pattern may help a person stabilize and manage their blood sugars.

However, this type of eating pattern may be unsuitable for some people and be difficult to maintain in the long term. Therefore, before reducing their carbohydrate intake, a person may wish to consult a healthcare professional or a dietitian.

There are three main types of carbs:

Sugars and starches raise blood sugar levels, but fiber does not cause a blood sugar spike, as the body is unable to absorb and break down this type of carb. As such, people may consider including carbs that are richer in fiber in their diet.

People may also refer to sugars and starches as simple and complex carbs. Simple carbs primarily consist of one type of sugar. The body breaks these carbohydrates down very quickly, which causes blood sugar to rise rapidly. Complex carbohydrates consist of three or more sugars that are linked together. They result in a more gradual release of sugar into the body, meaning blood sugar levels do not rise rapidly after a person eats them.

Some people may use the glycemic index (GI) to help them monitor how much sugar and carbohydrate they eat, which will, in turn, help them manage their blood sugar levels. The GI measures and ranks various foods by how much they cause blood sugar levels to rise.

Low GI foods describe those that score 55 or lower on the GI index. These foods include:

  • sweet potatoes
  • quinoa
  • legumes
  • low fat milk
  • leafy greens
  • nonstarchy vegetables
  • nuts and seeds
  • meat
  • fish

Maintaining a moderate weight can help a person better manage their diabetes. The ideal weight range for a person varies among individuals, but a doctor can help provide guidance.

Evidence notes a link between obesity and type 2 diabetes. Research also highlights the relationship between obesity and insulin resistance. Insulin is the hormone responsible for allowing glucose in the blood to enter cells.

At most meals, a person needs to follow portion guidelines. Eating a suitable portion size can make managing weight and controlling blood sugar levels easier. Many factors, such as weight, body composition, and activity levels, play a role in determining the ideal portion sizes, according to Diabetes UK.

A doctor or dietitian can offer more specific advice on appropriate portion sizes for a person.

Exercise has many health benefits and can help a person manage their blood sugar levels.

Notably, exercise can help by increasing insulin sensitivity, allowing muscle cells to use the hormone more effectively to take up glucose and use it for energy. This can help lower blood sugar in the short term. In the long term, regular exercise can help lower a person’s A1C test result.

Proper hydration is crucial for health and can help a person control their blood sugar levels.

Dehydration is the term for the body having less water than it requires. It can cause blood sugar levels to spike, as less water in the body means there is a higher concentration of sugar in the blood. Therefore, taking on more fluids can help lower blood sugar.

However, it is important to hydrate with water, as other beverages — such as fruit juices and sodas — can cause blood glucose to increase further.

Some people may consider using herbal supplements to help control their blood sugar.

According to Diabetes UK, while some research suggests that herbal supplements may have a positive effect, more evidence is necessary to support these claims. Additionally, some herbs can interact with other medications and result in side effects. As such, a person needs to discuss any supplements with a doctor before taking them.

Some supplements that may help include:

Stress has a significant effect on blood sugar levels. The body releases stress hormones when it is under tension, such as when a person is ill or experiencing emotional stress, and these hormones can raise blood sugar levels.

Evidence notes that managing stress through exercise and allowing time for rest and relaxation can help lower blood sugar levels.

Getting adequate sleep can help with diabetes management. Evidence indicates that most adults should aim for 7 or more hours of sleep per night.

Insufficient sleep can have various effects on the body, including:

  • increasing insulin resistance
  • increasing hunger
  • causing cravings for foods high in carbs and sugar
  • making it more difficult to maintain a moderate weight
  • raising blood pressure
  • impairing the ability of the immune system to fight infection
  • increasing the risk of depression and anxiety

Below are some common questions and answers about managing blood sugar.

Why is managing blood sugar important?

Keeping blood sugars at target levels can help people with diabetes avoid experiencing hyper- and hypoglycemic episodes. Having blood sugars outside the target range can result in sudden ill effects.

If a person is frequently unable to keep their blood glucose within these ranges, damage can occur throughout the body and lead to serious consequences. These may include: heart disease, kidney disease, nerve damage, feet problems, oral health problems, hearing loss, vision loss, and mental health problems.

How long does it take for blood sugar to go down?

Multiple factors, such as dietary patterns, health, and medications, can influence a person’s blood sugar levels. A person can seek a doctor’s advice on the best strategies to manage their blood glucose. As an individual’s blood sugars can fluctuate and go down quickly, it is important to monitor them closely.

Typically, medications, such as insulin, can help reduce blood sugars quickly.

How long does it take for blood sugar to go down with insulin?

Different types of insulin exist, and each type has a different onset and duration — meaning how long it takes to work and how long the effects last, respectively.

For example, rapid-acting insulin typically begins to work within about 15 minutes, has the strongest effect in approximately an hour, and lasts for a few hours. In contrast, ultra long-acting insulin usually starts to work within 6 hours and lasts for 36 hours or more.

How long does it take for blood sugar to go down with exercise?

Other methods, such as exercise, can help lower blood sugars for up to about 24 hours by making the body more sensitive to insulin.

Generally, it is advisable to exercise 1–3 hours after eating, as this is likely when blood sugar levels will be highest. However, it is important to check these levels before exercising and to check them regularly, particularly after any grueling activity.

If a person takes insulin, their risk of experiencing hypoglycemia may be highest 6–12 hours after exercising. Additionally, Diabetes UK advises caution if exercising with high blood sugar, as physical activity may cause levels to rise even higher.

Managing blood sugar levels to prevent hyperglycemia is vital to avoid serious complications from diabetes. A range of lifestyle interventions can help a person lower their blood sugar levels and keep them within the target range. Individuals can also work with their diabetes healthcare team to plan strategies and targets.