Can the timing of post meal exercise improve blood glucose targets in type 2 diabetes?

It is well known that regular physical activity and exercise is a highly effective blood glucose management tool for people living with diabetes. It can have a profound impact in lowering blood glucose levels (BGLs) and improving insulin sensitivity, as well as addressing other risk factors associated with common co-morbidities and diabetes complications including hypertension, high cholesterol and overall cardiovascular health.

Quite remarkably some of these benefits can be realised after just a single bout of exercise with evidence showing that insulin sensitivity can be improved for a period of 12, 24, even up to 72 hours following a single exercise session. This raises the question for many people living with diabetes – is there a ‘best’ time to exercise to lower blood glucose levels? Is there a time of day where the benefits of exercise can be harnessed more effectively?

Managing post-meal hyperglycaemia

The International Diabetes Federation (IDF) has identified that the frequency of post-prandial or post-meal hyperglycaemia has a strong association with developing diabetes-related complications such as retinopathy, neuropathy and nephropathy and secondary complications such as cardiovascular disease. Could this perhaps be an opportunity where the benefits of exercise could be used to assist people with managing post-meal hyperglycaemia?

While it’s normal for BGLs to rise after eating, an important part of diabetes management is to try and keep BGLs as close to the recommended ranges as possible. For people with type 2 diabetes, the general guidelines suggest keeping BGLs between 4–7 mmol/L before meals and between 5–10 mmol/L two hours after starting a meal (post-meal).

If your clients are consistently noticing that their post-meal BGLs are outside these ranges, there are several strategies they can use to help manage this.

Strategies to manage blood glucose levels

• Dietary advice – Speaking with a diabetes specialising dietitian about dietary modifications, such as altering the amount, type and spread of carbohydrate consumed throughout the day.
• Medication review – A medication review in consultation with their GP, Credentialled Diabetes Educator (CDE), or Pharmacist. There are several diabetes medications which specifically target post-meal glucose levels if this is identified as an issue. Your client may also benefit from a Home Medicines Review.

Could post meal exercise be added to this list?

Some studies show that meal-time exercise could be another tool that people have available to add to their diabetes tool kit.

Firstly, it is important to acknowledge that exercise is great for health, no matter the time of day it is performed. Encouraging physical activity and exercise whenever it is possible for someone living with diabetes should be one of the first priorities.

If however, post-meal BGLs have been identified as an issue, exercise has been shown to be a useful tool and could be used in conjunction with the strategies above to assist in managing spikes in BGLs seen following a meal.

A study tested this idea by recruiting people living with type 2 diabetes to perform 20 minutes of self-paced walking either immediately before, or in the 20 minutes after their dinner time meal. The results of the study showed that as little as 20 minutes of post-meal exercise was enough to show a positive response when compared to no exercise. One of the exciting findings from this research was that this blood glucose lowering effect can be experienced immediately after just a single bout of exercise.

While further research is needed in this area to establish a set of specific exercise recommendations around meal time, the research to date indicates that post-meal exercise both aerobic exercise (e.g. walking, jogging, cycling etc.) and resistance exercise (e.g. body weight exercises, weights, resistance bands) can have a significant impact on post-prandial BGLs. The intensity and duration of the exercise are important factors to consider with the greatest benefits seen as the energy expenditure of the exercise increases and when exercise is performed at a moderate intensity or higher.

What do these findings mean?

For people living with type 2 diabetes, timing exercise in the period following a meal can be an effective tool in helping to manage post-meal BGLs. This exercise could be anything that the person enjoys and is accessible to them at that point in time such as:

• Walking around the local neighbourhood
• Completing theraband exercises while watching TV (resources can be found at the diabetes shop)
• Performing some body weight resistance exercises from home such as sit-to-stands, step-ups and wall push-ups
• Cycling on a stationary bike while listening to music
• Dancing, cleaning the house, vacuuming – essentially anything that leads to continuous movement!

Type 1 diabetes

Unfortunately to date, there are very few studies investigating these effects in people living with type 1 diabetes. The available evidence indicates that post-meal exercise can have a similar positive effect on BGLs; however, more regular monitoring and insulin adjustments may be required to reduce the risk of experiencing hypoglycaemia. We recommend that people with type 1 diabetes, and type 2 diabetes who also require insulin, consult with their GP or CDE as additional changes may be required to ensure this exercise strategy is safe and effective.

Want to learn more?

Take your skills to the next level by enrolling in our Diabetes and Exercise course. If you’re an exercise professional, this course will boost your knowledge, skills, and confidence in applying exercise guidelines for people living with diabetes or related conditions. Plus, you’ll earn 11 CPD points or 10 CECs upon completion.