low sugar that comes and goes

Overview

Low blood sugar (called hypoglycemia) means the amount of glucose in your blood has dropped below what your body needs for energy. When it comes and goes, you have episodes of low blood sugar from time to time, with normal blood sugar between them. This can happen for many reasons, and it is not something to ignore.

It is common, especially for people with diabetes who take certain medicines. It also happens to some people who do not have diabetes, though not as often.

It most often affects people with diabetes, but it can also occur in people with other health conditions, in people who have had stomach surgery, or after long periods of fasting.

Symptoms

Common symptoms

• Shakiness or trembling
• Sweating
• Feeling very hungry
• Irritability or anxiety
• Racing heartbeat
• Dizziness
• Trouble concentrating

Symptoms in children

• Crying or acting cranky
• Being unusually sleepy or pale
• Sweating, often while asleep
• Not responding or seeming 'zoned out'

Symptoms in older adults

• Confusion or memory problems
• Dizziness or unsteadiness
• Slurred speech
• Falls or unexplained weakness

Causes

Main causes

• Taking too much of certain diabetes medicines
• Delaying or skipping meals
• Drinking alcohol on an empty stomach
• Exercising more than usual
• Not eating enough before physical activity
• Rare medical conditions, such as an insulin-producing tumor or hormone problems

Risk factors

• Having diabetes and taking certain medicines that lower blood sugar
• Irregular eating patterns or going too long without food
• Drinking alcohol, especially without eating
• Certain medical conditions, such as kidney, liver, or adrenal gland problems
• Exercising a lot without eating enough beforehand

When to see a doctor

See a doctor urgently if:

• If you have severe symptoms like fainting, a seizure, or unconsciousness, call your local emergency number right now.
• If someone cannot wake you or you cannot swallow, emergency help is needed.

Book a routine appointment if:

• If you notice symptoms of low blood sugar more than a few times a week
• If you have low blood sugar and do not have diabetes
• If your blood sugar meter shows low readings often, even without symptoms

Diagnosis

Your doctor will ask about your symptoms, when they happen, and what usually brings them on. They may want to check your blood sugar during a low episode. Sometimes, they will ask you to keep a record of your blood sugar levels and symptoms at home.

Tests that may be done

• Finger-prick glucose test
• Lab blood test
• Oral glucose tolerance test (for some people)
• Continuous glucose monitoring – a small sensor that tracks your glucose day and night
• Hospital-supervised fasting test (in certain cases)

What to expect at your appointment

You may be asked to keep a diary of your meals, activity, and symptoms. Your doctor may refer you to a diabetes or hormone specialist. The process can take time, but it is important to get an accurate answer.

Treatment

The first step is to bring your blood sugar back up when it is low with quick-acting carbohydrates. Then, you and your care team will work on preventing future drops. If you have diabetes, your medicine plan may need adjusting, but never change your treatment on your own.

Self-care at home

• Keep a small supply of fast-acting carbs with you, like glucose tablets, a sugary drink, or fruit sweets
• Treat early – as soon as you feel symptoms, not later
• Learn the '15-15' approach if your doctor teaches it: eat about 15 grams of carb, wait 15 minutes, then recheck
• Carry some form of medical ID, like a bracelet or card
• Tell people close to you what to do if you cannot help yourself

Medical treatments

Your healthcare provider may adjust your diabetes medicines, change when you eat your meals, or suggest a continuous glucose monitor. For other underlying conditions, your provider will plan the right treatment. All treatment should be guided by a qualified healthcare professional.

When is surgery considered?

Surgery is not a common treatment for low blood sugar. It may be considered in the very rare case of an insulin-producing tumor (insulinoma), but this is not something most people will need.

Living with this condition

Get to know your own warning signs and take action early. Keep a low-blood-sugar kit in your bag, at your desk, and by your bed. Try to eat meals at regular times and let your friends and family know how to support you.

Lifestyle tips

• Eat balanced meals at regular times
• Talk to your care team before making big changes to your exercise routine
• If you drink alcohol, do not drink on an empty stomach
• Check your blood sugar as often as your provider recommends

Diet and exercise

Eating regular meals with a mix of carbohydrates, protein, and healthy fats helps keep your blood sugar steadier. Whole grains, vegetables, and legumes are great choices. If you exercise, plan ahead and have a snack if needed.

Mental health and emotional wellbeing

Worrying about when the next low might happen can weigh on you. It may cause stress, anxiety, or poor sleep. These feelings are normal. Consider speaking to a counselor or joining a support group.

Prevention

Yes, many episodes can be prevented. The most important step is to understand why your blood sugar drops and work with your care team on a plan. If you have diabetes, adjusting medicines, meals, and activity is the key. For others, treating the cause often stops the lows.

Complications

If left untreated

• Confusion and difficulty thinking
• Fainting or falls that may cause injury
• Seizures
• Loss of consciousness, which is a medical emergency

Long-term outlook

With the right understanding and a good plan, most people can manage recurring low blood sugar and enjoy a full, active life. Even after a severe episode, you can make changes that greatly lower your risk of another one.

Find support

Local organisations

• NHS ↗ · United Kingdom

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