There are many things which can affect how the insulin is absorbed from the injection site into the bloodstream. Ideally, you need to be able to rely on your insulin being absorbed in a regular fashion from one day to the next. It is important that the correct injection technique is used. Insulin is absorbed most rapidly from the abdomen, then the arms, thighs and buttocks. Short acting insulins are best injected into the arms or abdomen.
Smoking can cause unpredictable or erratic blood glucose levels in some people.
Nicotine causes changes in small blood vessels and this, in turn, can affect the absorption of insulin from the injection site. Heat, massage and exercising a limb close to the injection site can increase insulin absorption. Sometimes this can cause a sudden drop in blood glucose levels and an unexpected hypo. Exercise Exercise can have a number of effects on blood glucose levels, depending on the duration and intensity of the exercise, as well as your food intake and insulin levels. Appropriate timing of insulin injections and meals is essential for good control.