I've Been tring to do some sort of a work out on a regular basis, but I have little tim efor that. My question is if I'm outside working in the lawn or whatever and I'm sweating I'm I burning fat?

Justin,

Sure, you're burning fat. But, you are also burning fat when you tie your shoe. The question is about the amount of fat you are burning.

The body burns fat just staying alive. One important bodily function is maintaining a fairly constant body temperature. If you are outside on a hot day, your body could sweat, in an effort to cool your body down, while you where just standing there.

The amount of sweat that you produce is not a good measure of how much fat that you are burning.

I could go for a hundred mile bike ride on a cold November day and not sweat a lick and still have burned off a lot of fat.

Measuring calorie expenditure and heart-rate is a better way of gauging the amount of fat you are burning.

J

Justin,

one remark. I see you live in the hot Florida. As a South Californian I very often experience the strange thing: sweating without VISIBLE sweating. If the heat is high, the fluid part of your sweat can evaporate so fast, that you do not see any moisture on your body, despite of heavy sweating.
During my weekend long (2+ hours) runs I usually lose 2-4 lb water, without any visible sweating. The only way to detect it from the thick salt layer on my body.
So if you try to do summer outside workout or work till you SEE your sweat, you can get dangerously dehydrated.

Take care:

Eva