World Diabetes Day: Diabetologist reveals the best time to check blood sugar to prevent sudden high and low levels

Ever wondered when the best time to check your blood sugar is? A diabetologist reveals the right timing that can make all the difference in managing diabetes.

Every year, millions of people around the world wake up to a routine that starts not with coffee, but with a small prick on the finger. That tiny drop of blood holds vital information about their blood sugar level. For those living with diabetes, it is a number that helps plan their day, from what they eat to what they should avoid. While you can easily do blood sugar monitoring in the comfort of your home, one simple question often causes confusion—when is the best time to check blood sugar? This World Diabetes Day, understand why timing matters and how it can help you spot patterns, make informed food choices, and adjust your medication more effectively.

Regular monitoring helps manage diabetes more effectively!(Adobe Stock)

What is diabetes?

Diabetes is a chronic condition that affects how your body turns food into energy. As per the World Health Organization (WHO), about 422 million people worldwide are living with diabetes. Here are two types of diabetes:

1. Type 1 diabetes: This is an autoimmune condition where the immune system destroys the insulin-producing cells in the pancreas. People with type 1 diabetes produce little to no insulin and rely on daily insulin injections or pumps.
2. Type 2 diabetes: "The most common form, affecting over 95 percent of diabetics globally, occurs when the body becomes resistant to insulin or does not produce enough of it," Dr Saket Kant, Senior Consultant, Endocrinology, Sri Balaji Action Medical Institute, tells Health Shots. It is often linked to lifestyle factors like diet, weight, and physical activity.

When to check blood sugar levels?

For type 1 and type 2 diabetes:

• Fasting blood sugar: Check in the morning before breakfast to understand how your body managed glucose overnight.
• Postprandial (after meals): Check 1–2 hours after eating to see how food affects your blood sugar.
• Pre-meal readings: These help adjust insulin doses or medication before eating.
• Before and after exercise: Checking before workouts ensures safe levels, while post-exercise checks show how physical activity impacts your blood sugar.
• Before bed: Monitoring at night helps avoid nocturnal hypoglycemia (low sugar during sleep).

For gestational diabetes:

• Fasting blood sugar: Measure in the morning before eating.
• After meals: Usually 1 hour post-meal to ensure blood sugar stays within the target range.
• Before bed: A bedtime check helps balance overnight levels and prevent spikes.

What is the normal range of blood sugar levels?

For type 1 and type 2 diabetes:

• Fasting blood sugar (before meals): 80–130 mg/dL
• Post-meal (1–2 hours after meals): Below 180 mg/dL
• HbA1c (average blood sugar over 2 to 3 months): Below 7%

For gestational diabetes:

• Fasting blood sugar: Below 95 mg/dL
• Postprandial blood sugar (1 hour after meals): Below 140 mg/dL
• Postprandial blood sugar (2 hours after meals): Below 120 mg/dL

These targets, set by the American Diabetes Association (ADA), may vary slightly depending on individual health conditions.

How to check blood sugar at home?

• Wash and dry your hands thoroughly.
• Prepare your glucose meter, test strip, and lancing device.
• Insert the test strip into the meter.
• Prick the side of your fingertip to draw a small drop of blood.
• Touch the blood to the strip, and your glucose meter will display your reading within seconds.

Many people now use continuous glucose monitors (CGMs) for real-time tracking, which can offer a broader picture of blood sugar trends throughout the day.

Why is checking my blood sugar so important?

Your glucose readings reflect how your food, exercise, and medication interact. According to the US Centers for Disease Control and Prevention (CDC), consistent monitoring helps prevent sudden spikes or drops, both of which can be dangerous.

Dr Kant adds, "Regular monitoring is not just about numbers. It is a feedback tool as it helps you understand your body better, make smarter food choices, and avoid long-term complications like heart disease, kidney problems, and nerve damage."

It also allows doctors to tailor treatment plans more precisely, adjusting medications or insulin as needed.