Exercise prescription for type 2 diabetes patients
Following on from the previous step on exercise intolerance in type 2 diabetes patients, this article looks at some of the exercise recommendations for this clinical cohort.
The following recommendations have been set for individuals with type 2 diabetes (Colberg et al 2010):
- Aerobic exercise: A minimum of 150 minutes/week of moderate intensity or, in moderately fit people, 60 minutes/week of vigorous exercise
- Resistance exercise: At least 2-3 days/week of moderate (50% of one-repetition maximum) to vigorous resistance training (75-80% of one-repetition maximum)
- Unstructured physical activity: Increase total daily unstructured (commuting, occupational, home and leisure time) physical activity
- Combining aerobic and resistance exercise: Combined aerobic and resistance exercise is recommended as it is more effective than either one alone
- Exercise counseling: Structured exercise counseling is recommended, but it is more effective in combination with supervised exercise training (Balducci et al, 2010, 2012).
- Flexibility: This may be included as part of a physical activity programme, although it should not be a substitute for other training.
Adjunct modality: Low-volume high-intensity interval training (HIT)
Many individuals with T2D cite ‘lack of time’ as a barrier to regular participation in exercise programmes. High-intensity interval training (HIT) is physical exercise characterized by brief, intermittent bursts of vigorous activity. Low-volume HIT is emerging as a time-efficient exercise strategy for improving health and fitness in people with or at risk for cardiometabolic disorders.
A practical model of low-volume HIT consists of 10 × 60 seconds work bouts at a constant-load intensity that elicits ∼90% of maximal heart rate, interspersed with 60 seconds of recovery. This means that only 10 minutes of exercise is performed over a 20 minutes training session (Gibala et al, 2012).
This practical, time-efficient HIT model is well tolerated by people with T2D, and preliminary studies suggest that it improves glycemic control (i.e regulation of blood sugar levels) in T2D (Little et al, 2011).
Exercise therapy has the greatest effects when it is individually prescribed and periodically supervised. Aerobic exercise should be prescribed relative to each participant’s maximum capacity (i.e VO2max) or intensity equivalent to aerobic and anaerobic thresholds (i.e lactate or ventilatory thresholds) (Ronald et al 2009). In supervised exercise programmes exercise sessions are normally supervised at least twice per week (either individually or in group settings) by qualified exercise professionals. Supervised exercise training in T2D has been shown to:
- Accelerate the kinetic response of VO2 during submaximal exercise
- Reduce blood glucose, lipid and blood pressure levels
- Increase physical activity (outside the supervised sessions)
- Increase exercise tolerance
Ultimately, it prevents or delays the development of chronic complications of diabetes.
The big challenge: long-term exercise adherence
An important objective of exercise training is to help individuals create and maintain their own, self-controlled programme of physical activity once the supervision has ceased. However, home-based unsupervised exercise has been shown insufficient to maintain benefits in glycaemic control and body composition obtained following a supervised exercise, mainly due to reductions in exercise adherence in T2D patients (Dunstan et al, 2005).
- We did a study where people with T2D initially trained for 12 weeks, exercising 3 times per week under the supervision of a qualified trainer, followed by 12 weeks exercising 3 times per week without supervision. However, for the unsupervised phase study participants were encouraged to train in the same health centre previously used in the supervised exercise phase.
We demonstrated that the unsupervised training was effective in maintaining benefits in exercise tolerance, VO2 max, VO2 kinetics and physical activity levels, while exercise adherence rates remained high (MacAnaney et al, 2012).
An effective strategy to educate and motivate participants to exercise on their own and ensure long-term exercise adherence could be to perform the unsupervised exercise phase in the same leisure centre used during the initial supervised phase as long as it is ensured that participants are familiar with the training routines and equipment used.
- As a healthcare professional, how do you prescribe and monitor exercise therapy in people with T2D?
- Has lack of time been a barrier to exercise for your patients? How have you addressed this?
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