Levemir is nice and reactive to dose adjustments. So on days when you aren't working out you can take your standard levemir dose as normal. On days when you are working out you can reduce your levemir dose to avoid hypos during and after exercise. So you might take a couple of units less, or 10-20% less levemir than usual on the morning of a workout and then a similar reduction in levemir the evening after a workout (to avoid post workout hypos). You need to figure out by your own trial and error how much of a reduction, if any, you need for your exercise. With something like kettlebells, depending on what kind of weight your using and how intense you are going you might find it actually raises your blood sugar. When you are doing anaerobic exercise you release adrenaline which works opposite to insulin so a lot of weight lifters will bolus for their exercise to try and combat the raise it causes.