Best time to check blood sugar: When and why

Diabetes patients must watch their diet, take medicines on time and test their blood sugar or blood glucose levels regularly. Keeping a check on blood sugar levels can help manage diabetes better, as well as avoid health problems such as heart and kidney diseases. You can easily do blood sugar monitoring in the comfort of your home. All you have to do is use a small, sharp needle to prick your finger and put a drop of your blood on a test strip. But if you are wondering if you should check this before eating or sleeping, we asked an expert about the best time to check blood sugar.

What is diabetes?

Diabetes is a chronic medical condition characterised by elevated levels of glucose (sugar) in the blood due to the body’s inability to produce or effectively use insulin, says endocrinologist and diabetologist Dr Piyush Lodha. Insulin, a hormone produced by the pancreas, is meant to regulate blood sugar levels by facilitating the entry of glucose into cells, where it is used for energy. When insulin production is not sufficient or the body’s cells become resistant to its effects, glucose collects in the bloodstream, leading to diabetes. It is a common condition, as about 422 million people across the globe have diabetes, as per the World Health Organization.

Diabetes is primarily categorised into three types:

1. Type 1 diabetes

It is an autoimmune condition where the immune system kills the insulin-producing beta cells found in the pancreas, resulting in little or no insulin production. Usually diagnosed in children and young adults, it requires insulin therapy for the entire life of the person with this type of diabetes, says the expert.

2. Type 2 diabetes

It is the most common form, with more than 95 percent of people with diabetes having type 2 diabetes, according to the World Health Organization. It is characterised by insulin resistance, where the body’s cells do not respond effectively to insulin, and eventually, the pancreas may not produce enough insulin. It typically develops in adults over the age of 45, but is increasingly being diagnosed in younger people, says the expert.

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3. Gestational diabetes

Some pregnant women may have gestational diabetes, which usually resolves after child delivery. It involves insulin resistance during pregnancy and can increase the risk of developing type 2 diabetes later in life.

Blood sugar range for people with diabetes

Blood sugar targets can vary, but the American Diabetes Association recommends the following –

1. For Type 1 and Type 2 diabetes

• Fasting blood sugar (before meals): 80-130 mg/dL
• Postprandial blood sugar (1 to 2 hours after meals): Less than 180 mg/dL
• HbA1c (average blood sugar over 2 to 3 months): Below 7 percent

2. For gestational diabetes

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

Why is it important to check blood sugar for diabetics?

Regular blood sugar monitoring is crucial, as it helps in:

1. Preventing complications

Frequent blood sugar monitoring allows for early detection of high or low blood sugar levels. This can prevent severe complications such as diabetic ketoacidosis, hypoglycemia, and long-term damage to organs like the heart, kidneys, and eyes, says Dr Lodha.

2. Adjusting treatment

Blood sugar monitoring helps in evaluating the effectiveness of current medications or insulin regimens. It allows for timely adjustments in therapy based on the blood sugar trends.

3. Lifestyle management

It provides feedback on how diet, exercise, and other lifestyle factors are affecting blood sugar levels. This helps in making changes about your diet and physical activity levels, says the expert.

When to check blood sugar?

The optimal times for blood sugar testing can vary based on the type of diabetes and treatment goals –

1. For Type 1 and Type 2 diabetes

• Fasting blood sugar: It should be checked in the morning before breakfast to assess how well blood sugar levels are controlled overnight.
• Postprandial blood sugar: It should be checked 1 to 2 hours after meals to understand the impact of food on blood sugar levels.
• Pre-meal blood sugar: Checking before meals helps in adjusting insulin doses or medication.
• Before and after exercise: Checking blood sugar before physical activity ensures it is within a safe range, and post-exercise monitoring helps understand the impact of exercise on blood sugar levels.
• Before bed: Monitoring before bedtime helps prevent nocturnal hypoglycemia.

2. For gestational diabetes

• Fasting blood sugar: Should be checked in the morning before eating.
• Postprandial blood sugar: Usually monitored 1 hour after meals to ensure levels are within target ranges.
• Before bed: Checking before bedtime can help manage blood sugar levels overnight.

How to check blood sugar?

Checking blood sugar levels involves the following steps –

• Wash your hands and after drying them, hold a blood glucose meter, test strips, and a lancing device.
• Place a test strip into the glucose meter, following the manufacturer’s instructions.
• Load a new lancet into the lancing device and set it to the desired depth.
• Use the lancing device to prick the side of a fingertip to get a small drop of blood.
• Touch the blood to the test strip then the meter will analyse it and display the blood sugar level on the screen.

Regular blood sugar monitoring can help you to effectively manage diabetes, and make decisions about the treatment and lifestyle adjustments.