The progressive 20 meter shuttle run test is a field test used as an accurate predictor of a persons Vo2 Max. It has strong correlations with results attained from very accurate laboratory tests. If you have already been assessed as having a Vo2 Max of 57.6 this would equate to Level 13 shuttle 2 on the bleep test, good luck.
Good advice from everyone. If it was me I would be looking at racing the Marathon with even Splits. Do you use a GPS watch to check your pace? Also Test your nutrition strategy during training ie what type of Breakfast sits comfortably while running. I would also try using whatever brand of sport drink is handed out during the race while training as your stomach might not agree with them on the day. If I were you I would also do some fast but short distance interval training to complement your longer runs. This will raise your lactic threshold which is probably causing you to feel sick. As for Hypothermia why not start your run with some gloves on? You can allways throw them away half way around the course if not needed.
Its allegedly going to be held on the 22nd July 2012. They are going through the licenceing stage at the moment. A guy at our club seems to be involved in some way. Wrong time of year for a marathon though.