You're doing everything you can in your home and office to be more eco-conscious and reduce your carbon footprint. But what about your fitness routine? As it turns out, some simple tweaks to your workout can turn your sweat a little greener.

Here are seven ways to make that happen:

1. Ditch the plastic water bottle

Only about 13 percent of water bottles get recycled, according to the Natural Resources Defense Council. There's also evidence that chemicals called phthalates and bisphenol A (BPA) may leach out of plastic bottles and into your water, affecting various hormones in the body. The solution? Switch to a reusable stainless steel bottle and carry it to the gym and everywhere else you go, says Ryan Kollock, CEO of Code Green Fitness in Laguna Beach, Calif. (BPA-free plastic bottles may also help you avoid some of these chemicals.)

2. Rethink your transportation

Can you walk or bike to your gym? "Driving less will help you save gas and reduce your carbon emissions," says Kollock. As a bonus, you'll burn extra calories. If you have to drive, head to the gym when you’re running other errands or are on your way to or from work so you don't make a separate trip.

3. Play outdoors

You don't need a gym membership to stay fit, especially if your budget's tight these days. Instead, step out your front door and walk, or cycle. "You can get just as good a workout outside as you would on cardio machines that consume energy," says Kollock. And don’t overlook park benches and playground sets, which you can use for strength training.

4. Reconsider your cardio habits

If you can't give up cardio machines, no worries. Just be more conscious about how you use them. Although treadmills are the most popular, they’re also the worst energy vampires -- unless you use an incline. "The motor has to work the hardest when the treadmill is flat,” says Adam Boesel, owner of the Green Microgym in Portland, Ore. "But when you add an incline, you decrease the amount of energy that treadmill uses by as much as half." In general, machines that use resistance to increase the intensity of your workout require less energy than treadmills, so switch to an elliptical or even a self-powered cross-trainer like the Cybex Arc Trainer, if possible. And if you have cardio equipment at home, unplug it when it's not in use, as it can suck energy even when turned off.

5. Buy used equipment

When purchasing home gym equipment, try to follow rule No. 2 in the reduce-reuse-recycle slogan. Scour newspaper ads for used equipment, or check out Web sites like eBay and Freecycle or stores that sell used sports equipment, like Play It Again Sports. Also look for environmentally-friendly workout gear, like yoga mats and exercise balls made of recycled or sustainable materials.

6. Recycle your soles

Ever stop to think about how many gym shoes you'll go through in a lifetime? Fortunately, you can recycle your footwear through Nike's Reuse-A-Shoe program, which turns 1.5 million shoes into running tracks, basketball and tennis courts, soccer and football fields, and playgrounds every year. Log onto Nike’s Web site to find a drop-off center near you. Or donate gently used shoes to Soles4Souls or One World Running.

7. Wear organic duds

Dress as close to the earth as possible by wearing eco-friendly organic clothing, which are made without pesticides or herbicides. You’ll find fashionable yet eco-friendly workout clothes made by companies like Prana, lululemon, Nau, Green Apple Active and Blue Canoe.

There are, of course, numerous other ways to green your active lifestyle. But by following the seven strategies above -- or even just a few of them -- you’re taking the right steps to improve your well-being and the health of the earth. “If we want future generations to be healthy and be able to enjoy the outdoors, we have to make changes now,” says Kollock.

Karen Asp is a fitness/health writer who writes for numerous publications, including Fitness, Natural Health, Men's Fitness, Prevention, Self, Shape and Women's Health. She's a contributing editor for Woman's Day and the Fit Travel blogger for AOL. Asp is also a certified personal trainer and group fitness instructor.

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