What is the amount of salt recommended for those engaged in several hrs. of vigorous exercise in summer?

Honest, I've never deliberately had salty food for the express reason of a long hot summer bike ride for several hrs. before stopping for the evening. Am referring to some of the self-loaded touring rides I've done over the years. I think my daily diet already has enough salt. Always found it was fluid, some good carbs, etc. But maybe I'm not seeing things right? Already I use a bit of soy sauce vs. the horrifying amount that I see often tv cooking shows or in recipes.

When on a bike trip, at motel/hotel/b 'n b, I figure the cook already has given the meal salt for my ham/sausage, eggs, etc.

Past few days, a series of news articles about the problem of ingesting too much salt in food and not realizing it.

http://www.theglobeandmail.com/life/...rticle1194148/

http://www.theglobeandmail.com/speci...hard-to-shake/

http://www.theglobeandmail.com/speci...rticle1192703/