Like "Low BG episodes are the pits! I'm unfamiliar with the action time of Novolin-N. If it "peaks", and you are trying to exercise when it is peaking, that might be the cause of your lows. I'm going to "google" Novolin-N to see if that will provide any info/clues. OK, here's the action times of your Novolin-N Onset: 1- 2 hours, Peak: 4-12 hours, Duration: 14 - 24 hours (up to 24 hours), It's like the NPH I used to take years ago before going on MDI of Novolog and Lantus. I much preferred the flexibility of MDI/Novolog and Lantus although that meant more shots...but it also meant not being tied to the clock to eat and greater flexibility to even skip meals and fewer low BG episodes. Are you also taking any oral meds? That would also be a factor."