Exercise has repeatedly been shown to improve glycemic control as assessed by glycated hemoglobin. However, changes in glycated hemoglobin do not provide information regarding which aspects of glycemic control have been altered. The purpose of this systematic review was to examine the effect of exercise as assessed by continuous glucose monitoring systems (CGMS) in type 2 diabetes. Databases (PubMed, Medline, EMBASE) were searched up to February 2013. Eligible studies had participants with type 2 diabetes complete standardized exercise protocols and used CGMS to measure changes in glycemic control. Randomized controlled trials, crossover trials and studies with pre-post designs were included. Average glucose concentration, daily time spent in hyperglycemia or hypoglycemia, and fasting glucose concentration were compared between exercise and control conditions. Eleven studies met the inclusion criteria and were included in the review. Eight studies had short-term (≤2 weeks) exercise interventions, whereas three studies had a longer-term intervention (all >2 months). The types of exercises utilized included aerobic, resistance and a combination of the two. The eight short-term studies were included in quantitative analysis. Exercise significantly decreased average glucose concentrations (-0.8 mmol/L, p < 0.01) and daily time spent in hyperglycemia (-129 minutes, p < 0.01), but did not significantly affect daily time spent in hypoglycemia (-3 minutes, p = 0.47) or fasting glucose (-0.3 mmol/L, p = 0.13). The four randomized crossover trials had similar findings compared to studies with pre-post designs. Exercise consistently reduced average glucose concentrations and time spent in hyperglycemia despite not significantly affecting outcomes such as fasting glucose and hypoglycemia.

Background We examined the hearing function in adults with and without type 1 diabetes (T1D) to investigate whether an association exists between hearing loss and duration of diabetes, haemoglobin A1C level, diabetes complications and levels of select serum and urinary biomarkers. Methods We measured pure tone audiometry (PTA) thresholds; serum levels of C‐reactive protein (CRP), vascular endothelial growth factor (VEGF), soluble receptors for advanced glycation end‐product (sRAGE); and urinary isoprostane in 30 adults with T1D (age 43.8 ± 11.4 years). We also measured PTA thresholds in 11 adults without diabetes (age 53 ± 5.5 years). Results 63.3% of adults with T1D had high‐frequency hearing loss. Among adults with T1D, those with hearing loss were older (48.2 vs 36.2 years old, P < .01), had a longer duration of diabetes (30.7 vs 21.2 years, P = .02), a greater prevalence of peripheral neuropathy (57.9 vs 9.1%, P = .02) and significantly lower median levels of sRAGE (1054.27 vs 1306.83 pg/mL, P = .03) compared to those with normal hearing. Adults with T1D between the ages of 40 and 60 years old, who had diabetes for ≥35 years, had significantly higher PTA thresholds at both 500and 8000 Hz than age‐matched adults without diabetes. Conclusions A significant proportion of adults with T1D have high‐frequency hearing loss before age of 60 that is positively associated with age, duration of diabetes and presence of peripheral neuropathy. Our results are in support of previous studies suggesting a potential protective role of sRAGE against AGE toxicity and diabetes complications.