For me, endurance exercise is where I really need salt to avoid cramping. The more hours exercising, the more salt/calories I need to ingest. High intensity doesn't hit my body quite the same way.

Just an anecdote, YMMV

Interesting! Did my first two day fasting this weekend and felt awesome the whole time. I broke the fast yesterday evening because I want to hit the gym today.

Do you continue the fast after HIIt or do you eat some protein after? How do you feel after such an intense workout in a fasted state?