The role of obesity and cardiovascular fitness in the impaired glucose tolerance of aging

Obesity and diabetes as accelerators of functional decline: can lifestyle interventions maintain functional status in high risk older adults?

Obesity and diabetes are known risk factors for the development of physical disability among older adults. With the number of seniors with these conditions rising worldwide, the prevention and treatment of physical disability in these persons have become a major public health challenge. Sarcopenia, the progressive loss of muscle mass and strength, has been identified as a common pathway associated with the initial onset and progression of physical disability among older adults. A growing body of evidence suggests that metabolic dysregulation associated with obesity and diabetes accelerates the progression of sarcopenia, and subsequently functional decline in older adults. The focus of this brief review is on the contributions of obesity and diabetes in accelerating sarcopenia and functional decline among older adults. We also briefly discuss the underexplored interaction between obesity and diabetes that may further accelerate sarcopenia and place obese older adults with diabetes at particularly high risk of disability. Finally, we review findings from studies that have specifically tested the efficacy of lifestyle-based interventions in maintaining the functional status of older persons with obesity and/or diabetes.

Short-term altitude mountain living improves glycemic control

The aim of this study was to investigate the effect of mountain living conditions and high altitude hiking activities on glucose tolerance. In study I, we performed an oral glucose tolerance test on nine untrained subjects before and after 3 days of mountain living. In study II, the same measurement was used to determine the effect of high altitude hiking in two distinct geographic environments; participants included 19 professionally trained mountaineers. We found that trained mountaineers displayed significantly better sea-level glucose tolerance than sedentary subjects of a similar age (p < 0.05). This result suggests that mountaineering training could produce a beneficial effect on glucose tolerance. More importantly, in study I we demonstrated that 3 days of high altitude living (altitude approximately 2400 m) was sufficient to improve glucose tolerance. Furthermore, hiking in a relatively flat plateau area (Pamirs highland area, China, altitude approximately 4000 m) generated significantly better improvement in glucose tolerance than hiking in a mountain that contained many rough hills at a similar altitude (Mountain Snow, Taiwan, altitude approximately 3800 m). In conclusion, we found that living at a high altitude for the short term can significantly improve glucose tolerance. Additionally, the improving effect of hiking at high altitudes on glucose tolerance appears to be influenced by the geographic environment. These preliminary results suggest that high altitude living conditions and activities may possibly be developed as potential natural medicines for the prevention and treatment of type II diabetes in the future.

Evaluation of physical fitness in patients with Type 2 diabetes mellitus

PURPOSE

The aim of this study was to compare functional capacity in 30 Type 2 Diabetic patients with 30 healthy non-diabetic control subjects.

METHODS

Physical fitness was evaluated using the "EUROFIT Physical Fitness Test Battery". This battery estimates body composition, cardiopulmonary, musculoskeletal and motor fitness.

RESULTS

Percentage of body fat (PBF) was higher in the diabetic compared with control groups (P<0.05) although body mass index (BMI) was similar. Biceps and suprailiac skinfold thickness were also greater in the diabetic group (P<0.05). The 6-min walking distance and VO(2max) were significantly lower in the diabetic group (P<0.05). The diabetic patients had lower values of the single leg balance test with eyes opened and closed. Jump-stretch, handgrip and side-bending of trunk tests were also lower in the diabetic patients.

CONCLUSION

Physical functional capacity is lower in Type 2 diabetic patients than in age-matched control subjects.

American College of Sports Medicine position stand. Exercise and type 2 diabetes

Physical activity, including appropriate endurance and resistance training, is a major therapeutic modality for type 2 diabetes. Unfortunately, too often physical activity is an underutilized therapy. Favorable changes in glucose tolerance and insulin sensitivity usually deteriorate within 72 h of the last exercise session: consequently, regular physical activity is imperative to sustain glucose-lowering effects and improved insulin sensitivity. Individuals with type 2 diabetes should strive to achieve a minimum cumulative total of 1,000 kcal x wk(-1) from physical activities. Those with type 2 diabetes generally have a lower level of fitness (VO2max) than nondiabetic individuals. and therefore exercise intensity should be at a comfortable level (RPE 10-12) in the initial periods of training and should progress cautiously as tolerance for activity improves. Resistance training has the potential to improve muscle strength and endurance, enhance flexibility and body composition, decrease risk factors for cardiovascular disease, and result in improved glucose tolerance and insulin sensitivity. Modifications to exercise type and/or intensity may be necessary for those who have complications of diabetes. Individuals with type 2 diabetes may develop autonomic neuropathy, which affects the heart rate response to exercise, and as a result, ratings of perceived exertion rather than heart rate may need to be used for moderating intensity of physical activity. Although walking may be the most convenient low-impact mode, some persons, because of peripheral neuropathy and/or foot problems, may need to do non-weight-bearing activities. Outcome expectations may contribute significantly to motivation to begin and maintain an exercise program. Interventions designed to encourage adoption of an exercise regimen must be responsive to the individual's current stage of readiness and focus efforts on moving the individual through the various "stages of change."