To help out with my rehydration for the 12 hour, I picked up 2kg or Endura Rehydration sports drink that was recommended by fellow riders and also my mates that play soccer.

Link: Endura Rehydration | Endura Sports Nutrition

I plan to use this during my training up to the race, and on the race day. I mixed up a batch yesterday to see how it went, and I found it rather sweet. After finishing the first bottle, I mixed another as a 25% reduction in powder amount. It tasted a lot better.

I drank 1 bottle this morning on the ride into work, and another during the day whilst at my desk. I noticed by around 2pm that I started to feel 'weird'. I thought it was because I needed to eat more, so inhaled a choc/peanut bar and an apple. Still felt 'odd'. During this time I had also drunk 1 bottle of normal water. Each bottle is around 1lt (roughly 33oz US I think?)

Rode home today starting off slow. About 10mins in and I started to feel better. Increased my intensity to 85% and rode the rest of the way fine - sipping on my 3rd bottle of sports drink mix along the way.

I did a bit of research once I got home about sports drink mix, and found that because electrolytes are absorbed by osmosis they’re dependent on the concentrations being accurate. Therefore, would it be safe to assume that if I deviate too much from the recommended mix, they can start to screw with my fluid/electrolyte balance?

Has anyone had this issue before?

I am trying to 'ween' myself on to these things from straight H20 to ensure my hydration is good for the race, but I cant drink stuff that is too sweet, but I also don't want to screw up my electrolyte balance.