We know that regular physical activity is associated with numerous health benefits for the person with diabetes. These include an improvement in quality of life, and a significant reduction in cardiovascular risk factors and mortality. Despite this many of our clients remain inactive. A recent study which looked at patients with diabetes over the age of 50 found that 54% did not meet physical activity guidelines (1). Of note is the fact that in this inactive group 25% overestimates their amount of physical activity.
This article will briefly review the current recommendations for physical activity, barriers to these recommendations and guidelines for those patients with diabetes that have complications. Lastly some possible solutions to help our clients become more active will be discussed.
The 2008 Canadian Diabetes Association Clinical Practice Guidelines for physical activity recommend the following:
- People with diabetes should accumulate a minimum of 150 minutes of moderate to vigorous intensity of aerobic exercise each week spread over at least 3 days of the week, with no more than 2 consecutive days without exercise.
- People with diabetes should be encouraged to perform resistance exercise 3 times per week
This is a lot of activity for a population that tends to be inactive
The reasons for the recommendations:
1. Aerobic exercise
During moderate exercise active muscles take up blood glucose. Although the liver produces glucose the blood glucose tends to fall as the muscles use up more glucose than the liver can produce. The muscles rely on carbohydrate to fuel muscular activity. Plasma insulin levels also fall and so the risk of hypoglycemia is very minimal in someone not taking insulin or insulin secretagogues.
In a joint position paper on type 2 diabetes and exercise the authors state that “A single bout of aerobic exercise can improve glucose tolerance for more than 24 hours but less than 72 hours” (2). The authors also state that “the effects are similar whether the physical activity is performed in a single session or multiple bouts with the same total duration”.
However it should be noted that blood glucose tends to rise during intense bouts of exercise due to a rise in catecholamine levels. This can persist for up to 1-2 hours.
2. Resistance exercise
The effect of resistance exercise in type 2 diabetes is not known (2). It is known however that resistance exercise can result in lower FBG for at least 24 hours in those with IFG.
3. Combined aerobic and resistance exercise
It is believed that a combination of aerobic and resistance exercise may be more effective than either type alone. Certainly resistance exercise leads to a greater muscle mass and thus increased blood glucose uptake. Colbert et al. (2) however suggest caution in the interpretation of combination training as the studies have had a greater duration of exercise and an increased total caloric expenditure (2). More studies are therefore needed to find the best overall fitness regimen.
Barriers/facilitators to physical activity
Studies have looked at barriers/facilitators to exercise in both type 1 and type 2 diabetes.
One study has looked at barriers to physical activity in patients with type 1 diabetes (3). In a group of 100 patients with type 1 diabetes the strongest barrier to exercise was fear of hypoglycemia. Fear of hypoglycemia as a barrier was followed by work schedule, concern about loss of control over diabetes and having a low fitness level. It is true that managing type 1 diabetes and exercise can be extremely challenging.
The authors agreed that teaching patients about insulin pharmacokinetics and using appropriate strategies to minimize hypoglycemia can be helpful in helping patients with type 1 diabetes be more active.
Of note, one study of 764 patients with type 1 diabetes has found that the most important factor in fear of hypoglycemia to be the frequency of severe hypoglycemia (5).
Interestingly one study has looked at performing resistance training before aerobic exercise on control in patients with type 1 diabetes (6). The study looked at 12 patients and found that doing the resistance training first improved blood sugar stability and reduced the duration and severity of the post exercise hypoglycemia. However this was a small sample size and the workout included 45 minutes of resistance training followed by 45 minutes of aerobic. Can we apply this to our own patients? My own workout includes 15 minutes of resistance training and 30 minutes of aerobics and the order does not seem to matter.
Facilitators of exercise
Studies have found that the following factors help to facilitate exercise participation: proximity to pleasant facilities or a safe place to walk, higher levels of self-efficacy (which reflects confidence in one’s ability to exercise) and one’s social support network. It seems that doctors provide on average exercise advice/referral in 18% of office visits (2). Supportive counselling and problem-solving around barriers with a health care professional can help to motivate patients. Many of our patients prefer walking and pedometer-based programs can be effective.
On the other hand, co-morbid conditions can de-rail patients from participation in exercise (4).
Complications of diabetes
Nephropathy and microalbuminuria
Exercise can improve physical function and quality of life in patients with kidney disease. Microalbuminuria can be worsened during exercise due to blood pressure increases but this does not mean that exercise need to be restricted (2).
Individuals with uncontrolled proliferative retinopathy should avoid activities that greatly increase intraocular pressure and hemorrhage risk (2).
Known heart disease is not a contraindication for exercise. Those with angina classified as moderate or high risk should begin exercise in a supervised cardiac rehabilitation setting.
Exercise is advised for anyone with peripheral arterial disease (2).
Individuals without active ulceration may participate in moderate weight-bearing exercise. Studies have shown that moderate intensity walking does not lead to an increased risk of foot ulcers in those with peripheral neuropathy (2).
One study has found that balance training in older individuals with type 2 diabetes can improve risk for falls (7).
Individuals with high blood sugars (>16.7 mmol/l) may take part in physical activity provided they are feeling well and well hydrated. This is not a contraindication as it may be in type 1 diabetes (2).
Prevention of diabetes
Regular physical activity can prevent or delay type 2 diabetes (2). Greater volumes of physical activity may provide the most prevention (2). In the diabetes prevention program lifestyle modification (dietary and weight loss goals and 150 minutes of weekly aerobic activity) reduced diabetes risk by 58%.
A new study (8) has found that weight training alone (30 minutes per day x 5 days per week) reduced the risk of type 2 diabetes by 34%. Weight training may offer another option to those who do not participate in aerobic activities. In this study a combination of weight training and aerobic activity reduced diabetes risk by 59%.
Helping our patients to become more active
- We can encourage our patients to move more during the day. One study has found that obese individuals sat for 2.5 hours more than lean counterparts (2). The lean subject’s activity came from walks of short duration. Pedometers may help patients to set goals. Simple ideas such as walking while talking on the phone can be helpful.
- The word exercise can have very negative connotations for many of our patients. Reframing exercise in a positive way with an enjoyment factor can be helpful.
- Encourage mild or moderate physical activity as this may be most beneficial to maintenance of regular physical activity participation (2). Think about just 5 or 10 minutes per day for some of our patients.
- Clearly many of our patients do better in a supervised setting. Consider referral to a rehabilitation program or a gym with personal trainers. Perhaps physiotherapy consults for the patient who is not active due to joint pain.
- What about adding Fido to the family? Dog owners who walk their dogs have many health benefits (9).
- It is recognized that it may be easier to motivate a person who does not yet have diabetes than someone with chronic disease (2).
Physical activity is an important part of diabetes management. Each patient needs to be assessed individually to determine barriers and motivators. Most patients can perform some type of activity and the diabetes educator may be the ideal person to start this discussion.
- Janevic MR et al. Overestimation of physical activity among a nationally representative sample of underactive individuals with diabetes. Med Care 2012;50(5):441-5.
- Colberg SR et al. Exercise and Type 2 Diabetes. The American College of Sports Medicine and the American Diabetes Association joint position statement. Diabetes Care 2010;33(12):e147-e167.
- Brazeau AS et al. Barriers to physical activity among patients with type 1 diabetes:Diabetes Care 2008; 31(11): 2108-9.
- Casey D et al. Understanding physical activity facilitators and barriers during and following a supervised exercise programme in Type 2 diabetes: a qualitative study. Diabet Med. 2010;27(1):79-84.
- Anderbro T et al. Fear of hypoglycemia in adults with type 1 diabetes. Diabet Med. 2010; 27(10):1151-8.
- Yardley JE et al. Effects of performing resistance exercise before versus after aerobic exercise on glycemia in type 1 diabetes. Diabetes Care 2012; 35(4): 669-75.
- Morrison S et al. Balance training reduces falls risk in older individuals with type 2 diabetes. Diabetes Care 2010;33(4): 748-750.
- Grontved A et al. A Prospective study of weight training and risk of type 2 diabetes mellitus in men. Arch Intern Med. 2012. Published online Aug. 06.
- Lentino C et al. Dog walking is associated with a favourable risk profile independent of moderate to high volume of physical activity. J. Phys Act Health 2012; 9(3): 414-20.