Working up a sweat doesn’'t have to have an impact on the planet.

When Eric Eckard laces up his sneakers and hits the road, it’s not just his own health that he’'s thinking about. Eckard is also concerned with the health of the planet.

To ensure that his workouts are as green as possible, he carries a reusable water bottle, uses secondhand gear and often runs outside instead of getting on the treadmill.

"“I know our natural resources are limited,"” says Eckard. “"So although it's just a drop in the bucket, I want to do my part to protect the environment.”"

Consider these options for making your workout more environmentally friendly.

Move Outdoors

Head outside for a human-powered workout. A 30-minute jog on the treadmill uses approximately .75 kWh of energy, which is enough power to light a Christmas tree for six hours.

Of course, not all exercise equipment requires an electrical outlet.

"“Working out on machines that aren'’t plugged in is a much better option,"” notes Elizabeth Rogers, author of Shift Your Habit: Save Money, Save the Planet (Three Rivers Press).

If it'’s not possible to get outside, work out at home with resistance bands and other gear that has a low impact on the planet.” Weight sets——either free weights or machines designed for home use——can help pump you up without having to flip a switch, while stability balls and similar gear can allow you to create an effective core-and-flexibility routine.

Go Organic

Your favorite workout outfit may turn heads, but it might be hard on the environment. According to the Organic Trade Association, it takes almost a third of a pound of chemicals to manufacture a single cotton T-shirt.

What’'s more, many major clothing manufacturers use cotton that has been genetically engineered to fight pests——and which may instead turn formerly benign insects into pest species.

Organic cotton, grown without pesticides, weedkillers or chemical fertilizers, is a better choice for towels, shorts, T-shirts, socks and other workout gear.

"“It'’s getting easier to find organic cotton clothing,”" notes Ronnie Cummins, national director of the Organic Consumers Association. "“Look for the organic label. It'’s against the law to call an item of clothing ‘organic’ unless it’s been certified under federal regulations.”"

When it comes to fitness clothing, organic cotton is not the only green option. You can also find clothes and sneakers made from bamboo, soy, hemp and coconut shells.

It’'s even possible to find running shoes made with recycled rubber soles. Read the labels or ask sales associates for more information about the fabrics and materials used in workout clothing.

While changing over your clothes closet, also look for natural soaps, shampoos and moisturizing lotions to make that post-workout shower a greener experience.

Is yoga your fitness routine of choice? You can go green, too.

Yoga pants, tanks and other apparel are available in hemp and organic cotton, and yoga mats are available in natural rubber and other eco-friendly options.

Choose Green Gear

What happens to all those elliptical trainers, cable machines and treadmills when we'’re done with them? They go to the landfill——an environmentally bad idea.

Instead of shopping for brand-new gear, consider secondhand equipment made from recycled materials, which have less of an impact on the environment.

Check out used sporting goods stores for weights and bikes. You can also hunt down used treadmills and canoes, along with gym bags and yoga mats made from recycled materials. If you have equipment you’'re no longer using, sell it at a garage sale or donate it to a not-for-profit.

Buying a reusable water bottle is one of the most environmentally responsible choices you can make. According to Rogers, it takes 1.5 million barrels of oil to make the number of bottles of water Americans drink annually.

"There are so many choices when it comes to buying a reusable water bottle,”" she says. “"There'’s no excuse not to have one.”"

Some fitness gear can be recycled, including sneakers. The rubber soles of old shoes can be recycled and turned into surface material for basketball courts, athletic fields, running tracks and playgrounds. Ask your local running store if they accept used sneakers for recycling.