Relationship between insulin resistance assessed by HOMA-IR and exercise test variables in asymptomatic middle-aged patients with Type 2 diabetes
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We investigated the relationship between index of insulin resistance (IR) and exercise test variables in middle-aged asymptomatic patients with Type 2 diabetes. Methods: 90 patients (48 men, 42 women; age: 49±6 yr) were included in the study. We used homeostasis model assessment for IR (HOMA-IR) index as index of IR. All patients were subjected to treadmill exercise test. Four subjects were tested positive (4.4%). Study patients were separated into three groups: group I (no.=26) HOMA-IR index <2.24; group II (no.=26) index 2.24–3.59; group III (no.=38) index >3.59. Results: group I had less frequency of cardiovascular risk factors than group II and III (p=0.001). Systolic blood pressure baseline as well as peak exercise values, were higher in group III than in group I and II (p=0.048 vs p=0.01, respectively). Higher total exercise time and peak workload were found in group I than group II and III (p=0.04). The recovery of heart rate (Δ HRpr) was similar among the study groups. We found significant negative correlations between HOMA-IR and total exercise time and peak workload. In addition we found significant negative correlations between age vs chronotrophic index (CI), Δ HRpr, and peak workload. There were also similar negative correlations between duration of diabetes vs CI and Δ HRpr. Conclusions: IR is associated with a variety of cardiovascular risk factors. Some exercise test variables point out changes of autonomic tone during exercise in elevated IR group. Negative correlation between HOMA-IR and peak exercise capacity (METs) may well confirm increased mortality in hyperinsulinemia.
Key-wordsType 2 adult diabetes insulin resistance exercise stress autonomic nervous system
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