Diabetes and Exercise

Exercise helps blood sugar control
Exercise helps blood sugar control

People with diabetes are encouraged to exercise regularly for better blood sugar control and to reduce the risk of cardiovascular diseases.

The reason for this is that muscles which are working use more glucose than those that are resting.

Muscle movement leads to greater sugar uptake by muscle cells and lower blood sugar levels.

Additional benefits of exercise include a healthier heart, better weight control and stress management.

Exercise is the common term used to describe any bodily activity that enhances or maintains physical fitness and overall health and wellness.

Why is exercise important?

As well as strengthening the cardiovascular system and the body’s muscles, many people exercise to keep fit, lose or maintain a healthy weight, sharpen their athletic skills, or purely for enjoyment.

Frequent and regular physical exercise is recommended for people of all ages as it boosts the immune system and helps protect against conditions such as:

In fact, it is known to cut your risk of major chronic illnesses/diseases by up to 50% and reduce your risk of early death by up to 30%.

Other health benefits of exercising on a regular basis include:

  • Improves mental health
  • Boosts self esteem/confidence
  • Enhances sleep quality and energy levels
  • Cuts risk of stress and depression
  • Protects against dementia and Alzheimer’s disease

Furthermore, exercise is free, can be carried out anywhere at anytime and has an immediate effect on your health.

What counts as exercise?

In the UK, regular exercise is defined by the NHS as completing 150 minutes of moderate intensity aerobic activity a week.

Aerobic activity at moderate intensity basically means exercising at a level that raises your heart rate and makes you sweat. This includes a multitude of sports. For example;

  • Fast paced walking
  • Light jogging
  • Bike riding
  • Rowing
  • Playing doubles tennis or badminton
  • Water aerobics

Cutting the grass, cleaning your home and other daily chores such as shopping don't count towards your 150 minutes of weekly exercise as advances in technology have made these activities far less demanding on the body than for previous generations, who were active naturally more active through work and manual labour.

However, the less time you spend sitting down, the better it will be for your health. Sedentary behaviour, such as sitting or lying down for long periods, increases your risk of weight gain and obesity, which in turn, may also up your risk of chronic diseases such as heart disease and diabetes.

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Are there any precautions I should take when it comes to exercise?

There are some exercise precautions which people with diabetes must take, however, when done safely, exercise is a valuable aid to optimal health.

Exercise precautions are designed to help people with diabetes avoid problems which can result from unwise exercise choices.

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.

Precautions for people on insulin or oral medication

Precautions to take if you take insulin or oral diabetes medication:

  • If your blood sugar level is less than 5.5 mmols/l (100 mg/dl) prior to exercise, take a carbohydrate snack prior to beginning the exercise.
  • If your blood sugar level is higher than 5.5 mmols/l (100 mg/dl) before exercise, it may not be necessary to take a carbohydrate snack before a light exercise session, but you may need extra carbohydrates during or following the exercise. Check your blood to see if your blood sugar dips below 4 mmols/l (70 mg/dl) following exercise.
  • If you experience hypoglycemia, follow the Carbohydrate Treatment guidelines. Follow up with your doctor. You may be advised to lower your medication on days you exercise if your blood sugar levels are well-controlled and usually within target range. 
  • For long duration and/or high intensity exercise sessions, plan extra carbohydrate snacks during the activity. Additional carbohydrates is suggested each 30 to 60 minutes of exercise (e.g. soccer game, hiking, biking, skating, etc).
  • Always carry a fast-acting carbohydrate food such as glucose tablets when exercising in the event blood sugar drops too low and hypoglycemia symptoms develop during exercise.
  • Wear a form of ID, which identifies you as having diabetes, particularly if you are exercising alone so that others may help you appropriately in the event something unexpected happens.

Severe hyperglycemia (with or without ketoacidosis)

Hyperglycemia (or high blood sugar) can occur when:

  • Too little insulin is available to counteract the liver's production of sugar which is stimulated by exercise hormones.
  • Too little insulin is available to assist glucose enter muscle cells quickly during exercise.
  • Too much fat is utilized for exercise because sugar is unable. Ketones levels rise in the blood.
Therefore, precautions to take against hyperglycemia include not exercising if:
  • Your blood sugar is above 13 mmol/s (240 mg/dl), especially with positive urine test for ketonuria, as exercising could result in higher blood sugars and lead to diabetic ketoacidosis. Follow your doctor's advice to lower blood sugar before recommencing exercise.
  • You are sick with flu, infection or another illness that is worsening blood sugar control.
  • If your blood sugar level is above 13 mmols/l (240 mg/dl) but less than 17 mmols/l (300 mg/dl), limit your activity to moderate intensity (walking, light biking), rather than a high intensity exercise (running, weight lifting, tennis).

Precautions for people with heart problems

People with heart conditions, in particular, should consult with their doctor before commencing an exercise regimen.

The British Heart Foundation advises people with existing heart conditions to avoid strenuous activity such as lifting weights, press ups or exercise which could result in chest pains or getting up from the floor quickly.

Worsening foot complications

As most exercise is done standing up, it is important to ensure that you are wearing adequate footwear. Foot problems can occur when:

  • Shoes fit poorly
  • Socks are not worn or are not absorbent
  • Friction or pressure points develop on feet

Therefore, in order to prevent foot problems, you should:

  • Inspect feet daily for signs of friction or pressure sores.
  • Speak with your physician, podiatrist or diabetes educator about proper foot care procedures.
  • Buy shoes which are well-made for the type of exercise you do and which fit you.
  • Consult a shoe retailer who specializes in exercise foot wear.
  • Buy cotton, absorbent socks.