Does sweating release toxins?

After practicing yoga in normal temperatures for years, I recently attended a heated yoga class (heated quite hot: 95 to 100 degrees!). The experience left me dizzy, nauseous, and completely enervated. Afterwards, I expressed my concern to the teacher, asking why the studio needed to be so hot. She "explained" that by sweating, supposedly the body releases "toxins" and that my nausea and dizziness must indicate that I need to "detox." Personally, I think I was suffering from heat exhaustion. I've heard this silly explanation more than once, as many people seem to believe toxins are released through sweat. But is that true??? And — next question — doesn't exerting oneself in extremely hot temperatures seem like a recipe for dehydration? Are their any benefits that make it worthwhile, or is all this heated yoga just nonsense?


Does exercising on an empty stomach maximize fat burning?

I have recently learned that in order to burn fat as a fuel, your body requires carbohydrate. Up until this point I had been doing cardio training first thing in the morning on an empty stomach, as I had read that this is optimum for fat burning. However, now I have a small carbohydrate snack before I train in order to prevent my body using lean muscle tissue as a fuel. Today I have again read in another book that training on an empty stomach first thing in the morning burns the most fat. I am a little confused over the best thing to do! I train with weights twice a week and do cardio three times per week. I do want to maintain my lean muscle, but am looking to reduce my body fat.


Do I need to stay home from class if I have chickenpox?

I've come down with chickenpox. Should I stay home from classes even though 90 percent of adults have already had it and are thus immune? If I take great care washing my hands and avoiding coughing anywhere but into the crook of my arm, will I be reasonably assured of not spreading it?


How contagious is measles and how is it spread?

A friend of mine is living with someone who might have just got measles (results pending). If true, and my friend has also got it, how contagious is it? I think it is measles, rather than German measles, which I had as a child. Does past illness provide any defense? That is, can you get it twice? I presume having had German measles does not provide any protection against measles.

How is it transmitted? Like a cold? (Physical contact, common contact with hard surfaces, and maybe airborne?)