<< For heavy lifting, yes. For cardio, no. >>

Uh, the cardio is exactly why I've increased my carbs. I just eat more
in general. Maybe I'm blessed with good genes, but people micromanage
too much. Just eat what you want and if you're exercising a lot, eat
more. So long as that "more" is not obviously stuff that wont' help
your cause such as oreo cookies, pizza, etc.

<< I eat low carb, and I do reasonably intense cardio for about 45
minutes most days. Not a problem. So long as you're aerobic, you can
fuel with bodyfat. >>

Whats your age/sex and what are your exercise goals? Some people DONT'
want to lose weight.

<< But yeah, the more you exercise, the more carbohydrate you can
tolerate. >>

Not only "can tolerate" but SHOULD have depending on age & lifestyle.

<< Though 5 step aerobics classes per week didn't keep my own personal
body from gaining weight on a grain-and-bean heavy diet. >>

But some people want to and/or need to gain weight.