An implanted medical device may detect the onset of impaired glucose tolerance or Type II diabetes. The implanted medical device may have additional functionality. For example, the implanted medical device may be a pacemaker or a pressure monitor, but may also monitor insulin-mediated glucose uptake by processing electrical signals from the heart. An implanted medical device that monitors insulin-mediated glucose uptake may be implanted in a patient who has not been diagnosed with impaired glucose tolerance or Type II diabetes, and may give the patient early warning if these conditions develop.