Well, did one yesterday, 55 miles R/T, to a library to check out some Atkins books! lol.

Some oddities:
It was very cold, at least for a Texan, low 30s.

It was very windy, in an unhelpful direction most of the way. (behind windbreaks on the way there, directly into my face for 15 of the miles back. 15+mph wind.

Did *NOT* eat breakfast of any kind. I'd eaten a large steak and green vegies dinner late, and didn't feel like eating.

I don't ride a roadbike. I ride a hybrid thats rigged heavy with lights and panniers, total bike weight is about 70lbs. Wind really beats me up good.

That said, it went like this. Warming up phase had more negative sensation than usual. About ten minutes in, I was at normal output, and HR matched perceived effort. With the wind, the speeds are all goofed, but seemed more or less as expected. At 48 miles while heading into the wind, I kinda ran out of excess salt, and didn't realize it; my speed cratered and my ability to climb or accelerate from a stop took a big hit..... The cold also locked up my aging hand joints and it became very challenging to shift down (up is a click, down is a smooth push), so that contributed. Despite that, I didn't have to stop, and didn't feel like I'd be forced to stop any time soon, though I had noticeably less power.

Something that has never happened, happened after I finished. I got cold. That I'll attribute to the LC side, as replacing the salt was easy enough at home...

Total calorie output, measured by monitor: 2500 kcal. That's much more than just stored glycogen could provide; I'll have to do a similar ride when the weather is more gentle, and see if some water+endurolyte pills, and maybe some salty dry-shredded meat can prevent the problem.