According to the symptoms you describe (the left arm and leg have become numb for 2 hours) and given your medical history (high blood pressure and cholesterol), you might have experienced some type of transitory ischemic attack (TIA). TIA is a kind of cerebral-vascular disorder where a thrombus stacks in a brain artery (embolia) and causes a temporary stop in blood flow (ischemia). The fibrinolitic system in the blood dissolves the thrombus and restores the blood circulation before irreversible brain damage (necrosis) can occur. That’s why the symptoms (no matter the severity) last only temporarily. The type of neurological symptoms of TIA depend upon the location of the ischemic area in the brain. TIA is not a serious condition by itself because all the symptoms disappear completely. However, TIA is a warning that something more serious is on the way, like a stroke. You must regularly control your blood pressure, cholesterol and blood sugar and take all the necessary medications for them if you want to prevent another TIA or a stroke.