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Review Question/Objective: The objective of this systematic review is to synthesise the best available evidence on the effectiveness of physical leisure time activities on glycaemic control in adult patients with diabetes type 2.

The specific review question is:

What is the effectiveness of physical leisure time activities on glycaemic control in patients with diabetes type 2?

Background: Type 2 diabetes results from the body's ineffective use of insulin. Diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both.Type 2 diabetes was previously called non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. 1 According to 2011 National Diabetes Fact Sheet 1, diabetes affected 25.8 million people of all ages of United States population during 2005-2008, include 18.8 million diagnosed people and seven million undiagnosed people. Among United States residents ages 65 years and older, 10.9 million, or 26.9 percent, had diabetes in 2010. Recent World Health Organization (WHO) calculations indicate diabetes kills more than one million people annually, almost 80% of which occur in low- and middle-income countries. Almost half of diabetes deaths occur in people aged under 70 years; 55% of diabetes deaths are in women. WHO projects that diabetes deaths will double between 2005 and 2030. 2

Type 2 diabetes is associated with older age 3, obesity 4, 5, family history of diabetes 6, history of gestational diabetes 7, impaired glucose metabolism 8, physical inactivity 9, and race 10. It is a common outcome of uncontrolled blood sugar and over time leads to serious complications including hypertension 11, blindness 12, kidney damage 13, lower-limb amputations 14, heart disease 15, and stroke 16. Good glycaemic control is a major goal in the treatment of type 2 diabetes mellitus to prevent and delay those severe long-term complications. 17 Physical activity is considered to be a substantial part of the treatment of type 2 diabetes mellitus, as well as diet and medication. 18, 19 Physical activity is a common physiological stressor that causes perturbation to glucose homeostasis and energy needs. 20

Several studies have reported the effects of physical activity on improving insulin sensitivity 21, 22, cardio-respiratory fitness 23, glycaemic control 24, and psychosocial well-being. 25 The American Diabetes Association suggests that people with type 2 diabetes spend at least 150 minutes a week on moderate-intensity physical activity (50-70% of maximum heart rate), or at least 90 minutes a week on vigorous physical activity (>70% of maximum heart rate). 26 Recent studies also indicate that moderate-intensity aerobic physical activity could help type 2 diabetes patients to maintain ideal glycaemic control. 27, 28 Boule et al 29 found physical activity training could reduce haemoglobin A1c (HbA1c) (control group vs. exercise group: 8.31% vs. 7.65%) by 0.66%. This is close to the effect of intense glucose-lowering pharmacological treatment found in the United Kingdom Prospective Diabetes Study. 30 A 1% absolute decrease in the HbA1c value is associated with a 15% to 20% decrease in major cardiovascular events 31 and a 37% reduction in microvascular complications. 32

According to Zhao, Ford, Chaoyang's report (2011), only 25-42% of older adults with diabetes mellitus met recommendations for total physical activity based on the 2007 American Diabetes Association and 2008 Department of Health and Human Services guidelines. 33 Various barriers to regular physical activity had been described, such as health problems, lack of time or energy, no exercise partner, lack of family support, and motivation and working time. 34, 35 An active lifestyle does not require complex exercise programmes. Instead, regular daily physical activity is believed to enable individuals to reduce the risk of chronic diseases and may enhance their quality of life. 36 Recently, it has been thought that, instead of structured physical activity, lifestyle physical activity is a better alternative for diabetes patients. Moderate or vigorous lifestyle or leisure time physical activities included jogging, walking, gardening, tai chi chuan, and qigong (an ancient Chinese breathing exercise that combines aerobics, isometric and isotonic movements and meditation). 37, 38 According to data from recent studies, moderate physical leisure time activities for at least 60 minutes every week can effectively improve glycaemic control in patients with diabetes type 2. 39, 40

Those measure indicators of glycaemic control including glycated hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), and postprandial plasma glucose (PPG) were used to assess glycaemic control in diabetic patients. 41 HbA1c value reflects the mean plasma glucose concentration over two to three months. 42,43 Fasting plasma glucose (FPG) and postprandial plasma glucose (PPG) reflect short-term plasma glucose change. Glycated haemoglobin is a form ofhaemoglobin that is measured primarily to identify the averageplasmaglucoseconcentration over prolonged periods of time. The fasting plasma glucose test measures fasting blood sugar levels and the postprandial plasma glucose test is often used to test the effectiveness of the body's carbohydrate metabolism and the ability to produce insulin. 44, 45

In 2010, Psaltopoulou et al gathered current information from meta-analyses on dietary and lifestyle practices concerning reduction of risk to develop type 2 diabetes 46. In 2009, Thomas et al completed a systematic review in which fourteen randomised controlled trials involving a total of 377 participants comparing exercise against no exercise in type 2 diabetes were identified. Trials ranged from eight weeks to twelve months duration. Compared with the control, the exercise intervention significantly improved glycaemic control as indicated by a decrease in glycated haemoglobin levels of 0.6% 47. This systematic review will differ from these two previously published reviews in that it aims to explore the effectiveness of different kinds of moderate or vigorous physical leisure time activities in improving glycaemic control in patients with diabetes type 2. A search of MEDLINE, DARE database, CINAHL, the Cochrane Library of Systematic Reviews and Joanna Briggs Institute Library of Systematic Reviews found no existing reviews or review underway on this topic.

(C) 2012 by Lippincott Williams & Wilkins, Inc.