I finished my 600 miles up for August on 8/29 so, I took 2 days off to recover since I had ridden quiet hard over the last week. Yesterday I went out for a 35 mile ride and felt really strong, in fact I had my personal best in average speed. Today I went out for a planned 50 mile ad it was all I could do to finish. I actually don't think I could have gone another mile and it took me about 3 hours to recover.
The only difference between this 50 and my other 50's is that I did not put Hammer Fizz tablets in my water bottles (I am out). I did take 3 Endurolyte tablets before I left (I usually take 3 on a long ride).
Can the lack of electrolyte replacement during the ride account for this?