Originally Posted by supcom
Unless you've been riding through a dust storm, it's salt.
Supcom:
You have given me good advise on other questions.
On this issue of salt loss please let me know: I did 100 miles/day in 100 degree and high humidity. I consumed 9 liters of water, ice tea and two sandwiches (Subway).
Did I deprive my system of salt? The last leg of the 100 miles seemed much harder and I had to slow down 10%.
I have done this same trip before, many times, in cooler weather without that problem.
In other words: Is it salt or just overheating?