Exercise is an important component of diabetes management, providing benefits for glycaemic control, cardiovascular health, muscular strength, physical function and overall quality of life.
However, the physiological responses to exercise and the associated safety considerations can differ between individuals with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).
Understanding these differences is essential for developing safe, effective and individualised exercise programs.
Exercise and Type 1 Diabetes
Type 1 diabetes is characterised by autoimmune destruction of pancreatic beta cells, resulting in an absolute or near-absolute deficiency of endogenous insulin.
Individuals with T1DM require insulin therapy to regulate blood glucose concentrations.
Exercise can significantly influence blood glucose levels, and the response depends on exercise intensity, duration, circulating insulin, recent food intake and other individual factors.
Hypoglycaemia
Hypoglycaemia is an important consideration for individuals using insulin.
During aerobic exercise, increased skeletal muscle glucose uptake may contribute to reductions in blood glucose concentrations, particularly when circulating insulin levels are elevated.
Hypoglycaemia may occur during exercise or several hours afterwards.
Preventive strategies may include:
Monitoring glucose before, during and after exercise.
Adjusting carbohydrate intake when required.
Considering insulin adjustments in consultation with the diabetes management team.
Having rapidly absorbed carbohydrates readily available.
Monitoring for delayed or nocturnal hypoglycaemia.
Hyperglycaemia and Ketones
High-intensity exercise may temporarily increase blood glucose concentrations due to the release of counter-regulatory hormones.
Individuals with significant hyperglycaemia, particularly when associated with elevated ketones, may require postponement of exercise and appropriate medical management.
Exercise should not be used as a strategy to lower blood glucose when significant insulin deficiency and ketoacidosis are present.
Exercise and Type 2 Diabetes
Type 2 diabetes is characterised by insulin resistance and progressive impairment in pancreatic beta-cell function.
Regular physical activity can improve insulin sensitivity, glucose uptake and metabolic health.
Both aerobic and resistance exercise provide important benefits.
Aerobic Exercise
Aerobic activities such as walking, cycling and swimming can improve cardiovascular fitness and glycaemic control.
For many adults with T2DM, a common recommendation is to accumulate at least 150 minutes of moderate-to-vigorous aerobic activity per week, distributed across multiple days.
Exercise recommendations should be individualised according to physical capacity, health status and relevant clinical guidelines.
Resistance Training
Resistance exercise improves muscular strength and can contribute to improvements in insulin sensitivity and physical function.
Resistance training is commonly recommended on two to three non-consecutive days per week, targeting major muscle groups.
Reducing Sedentary Behaviour
Prolonged sedentary behaviour is associated with adverse metabolic outcomes.
Breaking up extended periods of sitting with brief bouts of standing or light physical activity may help improve postprandial glucose regulation.
Important Clinical Considerations
Blood Glucose Monitoring
Monitoring requirements depend on diabetes type, medication use, exercise characteristics and individual risk.
People using insulin or medications capable of causing hypoglycaemia may require additional precautions.
Peripheral Neuropathy
Peripheral neuropathy may reduce protective sensations, balance, and increase the risk of foot injury.
Exercise selection should consider foot integrity, footwear, ulceration risk and any active complications.
Cardiovascular Disease
Diabetes is associated with a significantly increased cardiovascular risk.
Exercise prescription should consider known cardiovascular disease, symptoms, physical capacity and the need for medical evaluation.
Key Takeaway
Exercise provides substantial benefits for individuals with both type 1 and type 2 diabetes.
However, effective exercise prescription requires consideration of glucose regulation, medication use, associated complications and individual physical capacity.
A personalised approach, supported by appropriate monitoring and multidisciplinary care, is essential for safe and effective diabetes rehabilitation.
C. Johnston