Diabetes 101: Managing High and Low Blood Sugar

Andi is a Glucology brand partner.

Managing diabetes means being ready for both high and low blood sugar. Knowing how to spot, treat and prevent these swings helps you feel better day to day and protects your long-term health. Here's what you need to know.

What is blood sugar, and why does balance matter?

Blood glucose is your body's main source of energy, especially for your brain. Insulin helps glucose move into your cells. When levels stay in range, you tend to have more energy, think more clearly and lower your risk of complications. For reference, in people without diabetes:

• Fasting blood glucose is typically 70 to 99 mg/dL
• After meals, it usually stays under 140 mg/dL

Your own targets may be different, so agree on them with your care team.

High blood sugar (hyperglycemia)

For many people with diabetes, a reading above 180 mg/dL is considered high. Untreated, very high glucose can lead to diabetic ketoacidosis (DKA), which is a medical emergency.

Common causes

• A missed or incorrect insulin dose
• Higher-carb meals without enough insulin
• Illness or infection
• Stress or lack of sleep

Symptoms

Increased thirst and urination, tiredness, blurred vision and headache. Nausea, vomiting, stomach pain or fruity-smelling breath can be signs of DKA.

What to do

• Take a correction dose if your plan includes one.
• Drink water.
• If you take insulin, check for ketones when your glucose is over 250 mg/dL.
• Light activity like walking can help, but don't exercise if ketones are present.
• Get medical help if levels stay high, ketones are moderate or high, or you have symptoms of DKA.

Preventing highs

• Count carbs carefully and match your insulin as your care team advises.
• Ask your team about the best timing for mealtime insulin.
• Stay hydrated and get enough sleep.
• Look for patterns and review them with your care team.

Low blood sugar (hypoglycemia)

Low blood sugar is a reading below 70 mg/dL.

Common causes

• Too much insulin or certain diabetes medications
• Skipping meals or eating less than planned
• Extra activity without adjusting food or insulin
• Drinking alcohol without food

Symptoms

Shakiness, sweating, confusion, dizziness, a fast heartbeat, irritability or anxiety.

What to do: the 15-15 rule

1. Have 15 g of fast-acting carbs, such as glucose tablets, 4 oz of juice or regular candy.
2. Wait 15 minutes and recheck.
3. Repeat if you're still below 70 mg/dL.

Severe lows can cause loss of consciousness or seizures. Make sure the people around you know how to use glucagon and when to call 911.

Preventing lows

• Don't skip meals.
• Plan insulin and food around exercise with your care team.
• If you have overnight lows, ask about adjusting your basal insulin.
• Always carry fast-acting carbs.

Stress, illness and hormones

Stress hormones like cortisol and adrenaline raise glucose, illness can increase insulin resistance or reduce appetite, and hormonal changes such as the menstrual cycle can change insulin needs. Check more often during these times and work with your care team on any dose changes.

Making the most of monitoring

A CGM shows real-time trends and alerts, while a meter is useful for spot checks. Helpful times to check include before meals, two hours after meals, before and after activity, and at bedtime and on waking.

Understanding your insulin plan

Knowing your insulin-to-carb ratio, correction (sensitivity) factor and basal insulin needs helps you understand your meal and correction doses. Always talk to your endocrinologist before making significant changes.

Create an emergency plan

Teach family, friends and coworkers how to recognize highs and lows, how to give glucose or glucagon, and when to call 911.

For more on exercise, read is exercise helping or hurting your blood sugar?

Glucology is an Australian-owned brand, founded in Sydney in 2016. Trusted by 350,000+ customers worldwide, we design practical everyday accessories for people managing diabetes, including insulin cooling pouches, insulin pump belts and diabetes travel cases.

General information, not medical advice. Always talk to your diabetes care team about your care.