The insulin dose is easy to decrease if you know which insulin is having its main effect during the time of exercise. You should reduce the insulin that is most active during the period of heavy exercise. The figures in Chapter 7 show which insulin acts during each of the four periods. If extra morning exercise is planned, you can reduce or leave out the morning Humalog or Regular insulin. NPH or Lente insulin is never left out entirely.
People reduce insulin by different amounts.
You should reduce the insulin that is active during the period of exercise. Suppose you are receiving 30 units of NPH insulin in the morning and you have a soccer game in the afternoon. You would then receive 24-27 units of NPH insulin. If strenuous exercise is planned for all day, both the morning NPH and the short-acting insulins can be reduced. If strenuous exercise is planned for the evening, the evening Humalog or Regular insulin can be reduced or omitted.