Advice for Professionals
Initial medical assessment of patient with Type 1 diabetes in relation to exercise
Assessment of the patient
People with Type 1 diabetes tend to have four main problems when exercising these are;
- problems controlling their blood glucose during and immediately following exercise
- unexplained severe hypoglycaemia particularly at night
- reduced performance due to excessive fatigue and reduced muscle strength.
- difficulties gain or losing weight
It is important that a detailed history and examination is undertaken to deal with these issues.
Key things in History and examination
Current approaches to managing T1DM
- Patients need to check their glucose regularly when exercising (see monitoring glucose around exercise section)
- Patients who carbohydrate count and use carb/insulin ratios have more options to manage their exercise.
- High blood glucoses – make it difficult to build up muscle mass and glycogen stores post exercise so ideally HbA1c should be a good as possible.
Insulin regime
- It is difficult to manage patients who are performing regular exercise on premixed twice-daily regimes without incurring the risk of exercise-induced hypoglycaemia.
- Fast-acting insulin analogues (Insulin aspart (Novo Nordisk), lispro (Eli Lilly) or glulisine (Sanofi-Aventis)) have a shorter window of action than human, pork or beef insulin which can be helpful if exercising around meal times.
- The longer duration of action of the long-acting basal insulins whilst helpful in routine clinical care, can result in higher insulin concentrations during exercise and an increased risk for hypoglycaemia during endurance exercise and less flexibility in reducing dose post exercise
- In one clinical study NPH insulin (insulatard (Novo Nordisk), Humulin I (Eli Lilly)) and determir (Novo Nordisk) had lower risk of hypoglycaemia with exercise than glargine (sanofi-aventis)(see Plasma glucose and hypoglycaemia following exercise in people with Type 1 diabetes: a comparison of three basal insulins.
- In another study glargine had similar rate of hypoglycaemia after exercise as Degludec (Novo Nordisk). (see Similar risk of exercise‐related hypoglycaemia for insulin degludec to that for insulin glargine in patients with type 1 diabetes: a randomized cross‐over trial).
- No studies to data have looked at Insulin glargine u300 (Toujeo – Sanofi-aventis) or Abasaglar (Biosimilar Glargine – lilly) and exercise in Type 1 diabetes.
- Changes to insulin rates and background rates during and post exercise can be different to those on MDI regimes (see Pumps and exercise).
Insulin injection techniques
- The aim to reduce day-to-day variation in insulin absorption and to avoid accelerated absorption of insulin when exercising.
- Injection sites should be checked to ensure there is no lipohypertropy.
- Injection techniques should be checked to ensure that air shots are being given. If the patient is on NPH insulin resuspension should be carried out correctly.
- Needle sizes should also be checked - 4 or 5mm needles are to be recommended.
- Patients should also be educated to avoid injecting into areas that will be used in planned exercise (eg. thighs before cycling) because the increased blood flow will increase insulin absorption.
Hypoglycemia frequency and awareness
- It is important to get a detailed history of hypoglycaemia at each visit.
- Many will occur at night. Therefore information from partners, and from scheduled 2am and 4am blood glucose checks should be requested.
- Hypoglycaemia should be avoided because it may hamper performance and will increase the risk of hypoglycaemia during exercise.
- If hypoawareness is present then steps should be taken to improve this. If not possible then addition steps should be taken when exercising (see hypounwareness and exercise section).
Diabetes complications
- For most people with T1DM any activity can be undertaken and risk is minimal if people start at a low intensity of activity and gradually build up the intensity.
- Some diabetes complications restrict what people with T1DM, others suggest that further investigations should be done before exercise is started (see Exercise and microvascular complications and Exercise and macrovascular complications sections of this website).
- Feet will need to be examined to look for: ulceration, deformity and evidence of neuropathy.
- Eye report/photos should be looked at so assess whether the patient has retinopathy if so what level.
Review of calorie intake
- Ensuring adequate fuel and fluid replacements is one of the most important components in ensuring safe and effective training in people with Type 1 diabetes.
- A common cause of hypoglycaemia and of fatigue during and following exercise is simply one of insufficient calorie intake.
- For these reason, all patients should have their dietary intake assessed if doing more than 1 hour a day of moderate intensity exercise. Ideal this should be done by a dietician (see Fuel and fluid for exercise section of this website).
A detailed history of exercise program
- The type, duration and intensity of exercise will determine blood glucose fluxes both during and after exercise. Endurance events will tend to lower glucose (see Physiology of exercise and Types of exercise and their effects on blood glucose sections of this website).
- Anaerobic or intense exercise will tend to increase glucose during and on occasions after exercise (see physiology of exercise and Types of exercise and their effects on blood glucose sections of this website).
- This knowledge will influence the advice provided on what to do with starting glucoses (see Blood glucose and exercise for adults with T1D).
- Similarly, this knowledge may influence the advice given on carbohydrate intake (Carbohydrates for exercise for people on multiple daily injections and Carbohydrate for exercise for people on insulin pumps sections of this website) and insulin therapy (link).
History of performance in training and competition
- The approach to glucose management (for example the starting blood glucose) may need to be different in training and competitive events (see Blood glucose and exercise for adults with T1D).
- Exploring performance in these two settings will enable the optimal approach to be designed for each of these settings
Articles linked to this article
Exercise and microvascular complications
Exercise and macrovascular complications
Types of exercise and their effects on blood glucose
Blood glucose and exercise for adults with T1D
Carbohydrates for exercise for people on multiple daily injections
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