Notes
Focused on taking it easy, but also forefoot/mid-foot strike which may have been undoing. Suffered severe cramp in right calf ~100 meters after crossing the locks. Slowed to walk, then figured run was over and stretched for a couple of minutes. Decided to try to keep running and pain seemed to gradually diminish but calf is still sore an hour after.
Hands puffy and difficult to stretch upper body after - slight hyponatremia? Felt fine.