Diabetes is a lifelong condition that causes a person’s blood sugar level to become too high.
There are 2 main types of diabetes:
- Type 1 diabetes – where the body’s immune system attacks and destroys the cells that produce insulin
- Type 2 diabetes – where the body does not produce enough insulin, or the body’s cells do not react to insulin
Type 2 diabetes is far more common than type 1. In the UK, around 90% of all adults with diabetes have type 2.
What are the benefits of exercise for people with diabetes?
Regular exercise can have a positive impact on diabetes management, as well as general health. If you stay fit and active throughout your life, you’ll be able to better control your diabetes and keep your blood glucose level in the correct range. Controlling your blood glucose level is essential to preventing long-term complications, such as nerve pain and kidney disease.
The main benefits of doing regular exercise if you have type 1 diabetes are:
- Helps to lower blood pressure and bad cholesterol
- Positive effect on your mood
- Stress reliever
- Improves sleep
How does exercise affect diabetes?
When we’re looking at diabetes management, one of the most important benefits of exercise is that it increases insulin sensitivity.
This means that you’ll need less insulin for the same amount of carbohydrate, and it can also help bring down post-meal blood sugar spikes. You might be able to see this effect after about 1 or 2 days after you’ve exercised. So, regular aerobic activity is really important when you’re managing your type 1 diabetes.
Does this effect vary based on the type of exercise? E.g. cardio and resistance training?
Competitive sports can cause your blood sugar levels to increase. Your blood sugar, or blood glucose levels, are affected by different hormones. When you compete in exercises, like a football match, this can cause you to become nervous and stressed. Stress releases a hormone that affects your blood sugar levels making them harder to control.
There are three different types of exercise that can affect your blood sugar levels.
- Anaerobic exercise is high-intensity exercise over a short amount of time.
- Aerobic exercise is lower-intensity exercise that you do over a longer amount of time.
- ‘Stop, start’ is when you do aerobic exercise broken up by short spurts of high-intensity exercise.
Exercising when you have ‘insulin on board’ (IOB) – for example, when you exercise soon after a meal and still have some rapid insulin in your system – may result in a greater risk of hypoglycaemia and a greater need for carbohydrate to offset the IOB. This variable means that doing the same exercise, but at different times, can result in varying effects on blood glucose. It’s essential to know how much IOB you have at the start of exercise.
Studies show that there is a large variation in how subjects respond to exercise. What this means is that guidelines are very useful, as well as learning from others, but remember that you’re an individual and your body may respond differently to another.
Learn how different types of sports or training sessions affect your blood glucose by testing before, during and after exercise, keeping a detailed record to refer back to. Remember, you’re an individual so don’t be alarmed if your blood glucose level behaves differently to what you expected.
How should someone with diabetes eat before/after a workout?
Insulin on Board or IOB is the calculation that tells you how much insulin is still active in your body. If you have low amounts of active insulin at the start of exercise, it has some benefits that include being able to use more of your fat stores during exercise, less risk of a hypo and less carbohydrate needed during exercise to maintain your blood sugar levels.
When you’re preparing for a training session, try to aim to have little IOB during exercise, especially if you’re concerned about going low. This means giving thought to the timing of meals and insulin boluses and also giving thought to pre-exercise meals.
All pumps will display your IOB which is only reflecting the bolus insulin and not the basal rate or long-acting insulin.
If you take multiple daily injections, use an app which tracks active insulin or glucometers with bolus calculators.
If you’re worried about having hypoglycaemia when you exercise, you might end up with high blood sugar levels as a result. Below is guidance from www.diabetes.org for type 1 diabetes that you can use as a guideline before and during exercise so you can get the most out of your workout.
| Starting blood sugar levels | Recommendations (note: a rule of thumb) |
| Less then 5mmol/L | · Ingest 10-20g of glucose before exercise
· Delay exercise until blood glucose is above 5mmol/L |
| 5–8 mmol/L | · Ingest 10g of glucose before exercise
· Exercise can be started |
| 8–15mmol/L | · Low-intensity exercise can be started |
| Greater than 15mmol/L | · Check blood ketones
· If no ketones, perform low-intensity exercise and/or give small correction dose of insulin · If ketones less than 1.0mmol/L, consider small correction dose of insulin and perform low-intensity exercise and monitor blood glucose · If ketones between 1–1.4mmol/L, take correction dose and exercise after 1 hour and monitor blood glucose · If blood ketones above 1.5mmol/L, follow regular guidance received from diabetes team for treating ketones |
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.
How long should a workout be for someone with diabetes?
Aerobic Exercises
Aim to get at least 30 minutes of cardio (aerobic) exercise most days of the week. If the thought of finding 30 minutes too difficult, you can break up the exercise into shorter periods, say 10 minutes here and there, aiming for a minimum of 30 minutes at the end of the day.
Aerobic exercises include:
- Tennis
- Dancing and Zumba
- Jogging/Running
- Walking
- Basketball
- Swimming
- Biking
Try to build up to 30 minutes gradually by adding a few minutes to each walk or exercise every other week until you can manage 20-30 minutes at a time. But don’t stop there—try to keep adding a few minutes over time to reach 60, even 90 minutes, a day to keep building your duration and fitness.
When should someone with diabetes NOT exercise?
For type 1 diabetes: When your blood sugar is too high, it can lead to hypoglycemia. This can happen when you are very dehydrated. If your blood sugar is high (for example, over 300 mg/dL) and you have ketones, do not exercise. If your blood sugar is high (for example, over 300 mg/dL) and you do not have ketones, exercise with caution.
Hypoglycemia can occur if a person who is taking blood sugar lowering medication has:
- Eaten too little carbohydrate (fruit, milk, starch) relative to the exercise
- Taken too much medication relative to the exercise
- Combined effect of food and medication imbalances relative to the exercise
Those who do not take diabetes medication do not need to take these precautions. Drink plenty of water before, during and after exercise to stay well-hydrated.
At Private GP Extra, patients have access to highly experienced GPs across the North West of England, at a time to suit them. Our doctors provide a personalised service, with continuity of care for every person, and can also offer a smooth and rapid onward referral to a specialist, if required. To book an appointment with one of our GPs, please visit https://www.privategpextra.com/appointments/ or call 0161 428 4464.
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