Management of type 2 diabetes: A handbook for general practice

Lifestyle interventions for management of type 2 diabetes

Physical activity

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Last revised: 17 Sep 2020

Grade: C

Children and adolescents with type 1 or type 2 diabetes or at high risk of type 2 diabetes should engage in 60 min/day or more of moderate- or vigorous-intensity aerobic activity, with vigorous muscle-strengthening and bone-strengthening activities at least three days/week

Grade: B

Most adults with type 2 diabetes should engage in 150 minutes or more of moderate-to-vigorous intensity aerobic activity per week, spread over at least three days/week, with no more than two consecutive days without activity

Grade: B

Additionally, adults with type 2 diabetes should engage in resistance exercise:

  • 2–3 sessions/week on non-consecutive days (Grade B)
  • for a total of at least 60 minutes per week (Consensus)

Grade: B

All adults, particularly those with type 2 diabetes, should decrease the amount of time spent in daily sedentary behaviour

Grade: C

Prolonged sitting should be interrupted every 30 minutes for blood glucose benefits, particularly in adults with type 2 diabetes

Grade: C

Flexibility training and balance training are recommended 2–3 times/week for older adults with diabetes; yoga and tai chi may be included based on individual preferences to increase flexibility, muscular strength and balance

These recommendations are drawn from the most recent recommendations from organisations including the National Health and Medical Research Council (NHMRC), the Scottish Intercollegiate Guidelines Network (SIGN), Diabetes Canada, the American Diabetes Association (ADA) and other relevant sources. Refer to ‘Explanation and source of recommendations’ for explanations of the levels and grades of evidence.

Physical activity is one of the cornerstones of diabetes management. Regular physical activity of any kind can have a favourable impact on glycaemic control, CVD risk and overall mortality.6 However, more structured, specialised and individualised exercise prescription can achieve superior benefits.10

The goal is for patients with diabetes, impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) to accumulate a minimum of 210 minutes per week of moderate-intensity exercise (or 125 minutes per week of vigorous-intensity exercise), with no more than two consecutive days without training. This weekly total should include at least two moderate-to-vigorous resistance training sessions for a total of at least 60 minutes. These exercise amounts will establish and maintain muscular fitness and aerobic capacity.4

It is recommended to refer patients with type 2 diabetes to an accredited exercise physiologist for the prescription of a safe and effective exercise intervention.

Aerobic exercise

In people with type 2 diabetes, aerobic exercise (eg walking, cycling, swimming) reduces HbA1c, triglycerides, blood pressure and insulin resistance.10

Aerobic exercise intensity can be set as a percentage of estimated maximal heart rate (HRmax) using the equation 208 – 0.7 x age [years].11,12 For moderate intensity, 55–69% of HRmax and for vigorous intensity 70–89% of HRmax can be used.4

Alternatively, ‘moderate’-intensity aerobic exercise is defined on rate of perceived exertion (RPE) scales as ‘somewhat hard’, and ‘vigorous’ as ‘hard’. Using the talk/sing test, a person is doing moderate-intensity exercise when they can comfortably talk but can’t sing, and vigorous is when they are unable to talk comfortably.

Resistance exercise

Resistance, or strength, training involves activity such as using free weights, resistance machines or body weight. ‘Moderate-to-vigorous’ resistance training can be defined as 2–4 sets of 8–10 repetitions of 8–10 exercises, with rest intervals of 1–2 minutes.4

Resistance training reduces HbA1c, although to a lesser degree than aerobic exercise.13 However, combining aerobic and resistance training appears to be superior compared with either alone.14 Both types reduce CVD markers similarly,13 and a single bout of either may have a similar acute effect.15

When advising patients about physical activity, general practitioners (GPs) should:

  • emphasise that some physical activity is better than none10
  • discuss the importance of reducing sedentary behaviour – advise patients to interrupt prolonged sitting every 30 minutes for blood glucose benefits
  • explore the risks and benefits of different forms of physical activity for the individual, taking into account whether the patient is already physically active
  • explain the importance of varying intensity of exercise levels
  • explain the importance of following the chest pain/discomfort and/or diabetes symptom management plan.16

Pre-exercise health assessment

Asymptomatic sedentary people with diabetes who wish to undertake low-to-moderate activity should have CVD assessment as part of usual diabetes care; however, those identified as having CVD risk on screening tools, or who have existing atherosclerotic or functional cardiovascular disease, may require more specific physical assessment prior to engaging in moderate- to high-intensity exercise. Existence of diabetes complications may require specific advice – refer below.

When prescribing a physical activity program, the GP should take a careful history and be aware of the following:

  • Special attention needs to be paid to exertion-induced symptoms, chest or abdominal discomfort, claudication or syncope.
  • People with type 2 diabetes frequently have silent macrovascular disease.
  • For patients with hypertrophic obstructive cardiomyopathy, heavy weightlifting and high-intensity aerobic exercise are not recommended.17
  • For patients with long QT syndrome, exercise may trigger a cardiac arrhythmic event.17
  • Vigorous exercise is contraindicated for those with proliferative retinopathy, and for three months after laser retinal treatment.17
  • Exercise may be relatively contraindicated in patients with peripheral neuropathy, a history of recurrent falls or uncontrolled hypertension.17
  • A foot assessment should be carried out and patients advised about the importance of appropriate footwear during exercise.
  • Referral to an accredited exercise physiologist is recommended.

Any symptoms suggestive of CVD need to be actively investigated.

Safety advice during and after exercising

People with diabetes should be advised to moderate or cease their activity if they develop cardiovascular symptoms or feel unwell.

Patients with claudication need to be encouraged to continue physical activity under appropriate clinical supervision.

Managing blood glucose levels

People using insulin or sulfonylureas (or combinations including these) need to be aware of potential delayed effects of physical activity on blood glucose levels (BGLs) – in particular delayed hypoglycaemia. Post-exercise hypoglycaemia can occur 12–15 hours after exercise, but is still a risk up to 48 hours after cessation of activity.10

Advise patients on how to recognise, prevent or manage hypoglycaemic events, including potential post-exercise hypoglycaemia (Box 1). Clinical advice should be given to all patients to stop physical activity if they experience symptoms of hypoglycaemia and to discontinue further physical activity until reviewed by their GP or other health professional.

Box 1. Advice for patients to recognise, prevent or manage glycaemic events when exercising

  • Do not begin exercising if you have experienced a hypoglycaemic event within the previous 24 hours that required assistance from another person to treat (severe hypoglycaemia ) or if you are feeling unwell.
  • Check BGLs before and during exercise, especially if using insulin or sulfonylureas; check every 30–45 minutes during exercise, and adjust medication and carbohydrate intake as appropriate.18
  • The ideal pre-exercise range for blood glucose is 5.0–13.9 mmol/L.10
  • If pre-exercise BGL is <5 mmol/L, and you are taking insulin or a sulfonylurea, you are at risk of a hypoglycaemic episode during or after exercise. Ensure you have access to additional carbohydrates as per the advice of an endocrinologist, credentialled diabetes educator or accredited practising dietitian.
  • Be aware that delayed hypoglycaemia can occur up to 48 hours post-exercise.
  • Carry a rapid-acting glucose source at all times (eg glucose jelly beans, or glucose gel/drink).

Other exercise safety advice

  • Advise patients to wear correct supportive footwear – especially if there is neuropathy, vascular disease, abnormal foot structure or previous foot ulcer/s, in which case the advice of a podiatrist with an interest in high-risk feet should be sought. This advice would also include the appropriateness of ‘jolting’ exercises such as running, skipping and jumping.
  • Advise patients with neuropathy or peripheral arterial disease to check their feet daily and after physical activity for blisters, warm areas or redness.

Aboriginal and Torres Strait Islander point

Many Aboriginal and Torres Strait Islander people are involved in physically demanding sporting and cultural activities, and this should be encouraged for all people with diabetes.

For Aboriginal and Torres Strait Islander patients, GPs should be aware of activities or programs that are affordable, appropriate and accessible. These might be run by local community groups.

A careful history in the context of a trusting doctor–patient relationship may bring about better understanding and opportunity.

For more information, refer to the Australian Institute of Health and Welfare report on Healthy lifestyle programs for physical activity and nutrition.

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