Adjusting carb intake:
When I'm running/cycling I know my rough BGL drop over a set period of time. To do this, take a reading before and after a set period, i.e. 30mins at a constant pace. Once you know your BGL drop, you can accommodate this with gel sachets during exercising. These ones work pretty well, but there are loads on the market:
http://www.chainreactioncycles.com/...gclid=COuVw_aX1MwCFSsz0wodmw4Mig&gclsrc=aw.ds
Adjusting insulin intake:
I don't really adjust anything when I excercise. But it's best to avoid exercising during the peak of your fast acting insulin. In other words, it's best not to go out 1-3hrs after taking Novorapid insulin (this is what I'm on but you may use a different insulin so check the leaflet supplied). I tend to have maybe a 30g carb breakfast and not take any insulin if I'm going out shortly after. This will save you on gel sachets also. Carbing up is a good way to avoid hypos when exercising, but carb up too much and you'll run the risk of developing ketones during exercise.
Avoiding hypo near end:
Hypos can be avoided by regular BGL checks. Obviously when running this is a major pain and something I don't bother with myself. If you keep a steady carb intake whilst exercising then this should avoid the hypos. Also, hypos can occur well after you have stopped exercising - so it's important to eat something after finishing the workout and keep an eye on those levels.
Hope this has helped some, there will be other forum members who are a lot more clued up that me and will post here soon
P.S. My dietician recommended this site, it's very good:
http://www.runsweet.com/
Cheers!
Grant