Glucose Control: Why Timing Your Exercise After Meals Matters

If you have diabetes, you’re always fighting to keep blood sugar under control. Here’s a way to dial up your efforts: Consider the timing of your workouts after meals.

Exercising soon after eating has positive effects on blood sugar, says endocrinologist Betul Hatipoglu, MD.

Another plus? Doing this can cut your risk of heart disease.

How soon after meals? This can vary by the person. Here’s how to tell when it’s best for you.

Why it’s better to exercise soon after eating

Glucose levels hit their peak within 90 minutes of a meal, according to a 2017 study published by the journal Frontiers in Endocrinology.

Those with type 2 diabetes are supposed to keep levels at 160 mg/dl within two hours of a meal.

Because exercising reduces blood glucose concentrations, it’s a good idea to start exercising about 30 minutes after the beginning of a meal, researchers concluded.

While this is a solid guideline, it can vary for different people. Read on to find out how to ensure you’re in the safe zone for exercise.

How to tell if it’s safe to exercise

Before you begin your workout, start by measuring your blood sugar, Dr. Hatipoglu says.

When you initiate exercise, your body releases stress hormones, which can briefly raise your blood sugar.

If you have diabetes and your body doesn’t manage blood sugar well, it can increase too much during the first half hour of exercise before it begins to lower.

“If you start exercising with very high blood sugar, it might be dangerous,” she says. “You might need to wait for it to go down a bit before starting your workout.”

She offers four tips for ensuring that your glucose levels are safe for exercise:

1. If your blood sugar level is between 150 and 180, you are in a healthy range.
2. If your level is lower than 140 and you take insulin, you may need to eat 15 grams of carbohydrates prior to exercise so the level doesn’t drop too low.
3. If your level is really high — 300 or more — postpone exercise for a bit and try taking a little insulin before starting.
4. If you take insulin, check your blood sugar level after exercise to ensure that you have enough fuel. This is particularly important if you are starting a new exercise program.

The American Diabetes Association recommends about 150 minutes of moderate exercise or 75 minutes of rigorous exercise weekly.

Take extra precautions with evening exercise

Exercise does two things for those who have type 2 diabetes, says Dr. Hatipoglu.

First, your muscles need energy to work. To feed them, your body burns sugar as an energy source, lowering the glucose levels in your blood.

Second, when you exercise regularly, it helps your body use insulin more efficiently. This can lower your blood sugar levels for up to 12 hours after you exercise.

Also, keeping blood sugar low on a regular basis can dramatically reduce your risk of heart disease, Dr. Hatipoglu says.

Every person reacts a little differently to exercise, so she recommends tracking your blood sugar levels for four to five hours after post-meal exercise to see what your trend is. This can help you determine if your levels are healthy or drop too much.

This is particularly important if you exercise in the evening.

“Especially after dinner, you need to know what your body will do when you exercise,” she says. “If you go to bed and glucose drops it can create a dangerous clinical situation.”

Exercising after a meal is a good way to reduce blood glucose levels and lower your risk of complications from diabetes, including heart disease.

But, before starting or changing your exercise regimen, talk with your doctor to determine what is best for you.