Gastric distress is one of the most common reasons people fail to complete and ultra endurance cycling or running event. Here are some tips on how to deal with this sensibly and safely.
By far the best scenario is to avoid gastric distress altogether. You can do this by:
Hydrating well
Training your gut to take on the energy you need in training runs
Developing a list of foods that you know you can safely eat during your event. You can check out my article on EAT for more details.
When you start to feel sick and/or notice that food is not going down quite as well as you would like there are a few things you can do which might offset the nausea:
Loose bowels are the last thing you want when you are doing an ultra event as you will be getting rid of a lot of fluid making you dehydrated. A good way to avoid this is to make sure you only eat things you have tried and tested in training and are confident agree with you. Low fibre options both during and before your event should help make sure you are not too loose.
It's a good idea to be prepared for any bowel movement with methods of keeping clean and dry to prevent soreness (a small packet of wet wipes, some emollient cream like savlon just in case).
In the short term taking something to stop the unwanted bowel movements can help, but can also store up problems for further down the line in multi-day events.
One loose bowel movement however, whilst uncomfortable might be something you can recover from if you make sure you take on plenty of fluids and electrolytes.
Loose bowels are not to be confused with diarrhoea caused by infection. If you are ill and carrying an infection causing you to have liquid stools, run a temperature and causing gastric pain the safest thing to do is stop and seek medical help.