I learned something this week...

I recently switched to using an exercise ball for my chair at work. This is something I've been contemplating for a while, and I have thought it a good change so far. With one notable exception...

Sitting on an exercise ball after eating is not a good idea. It took me about a week to figure out the connection, but sitting on one after eating was causing bad stomach cramps. It makes sense (now) - traditionally, humans used to rest by lying down after eating, and so gave their bodies a chance to process the food without any extra stress on the body. But by sitting on the ball, you have to tighten your core muscles (transverse abdominus) to maintain posture, which places a lot of pressure on the stomach if it's trying to digest.

So, I now switch back to a normal chair for an hour after eating. Problem solved. Not related to running at all, but useful info none-the-less. I couldn't find anything about this with a google search.