Aerobic exercise is the best activity for reducing body weight and fat mass in obese individuals, according to a study published in Journal of Applied Physiology in 2012. Reducing body weight is of key importance in managing obesity, as extra body weight increases the stress on joints and organs systems.

Because of this stress, aerobic exercises for obese people should be low-impact. Luckily, low-impact cardio activity is just as effective as other types of cardio in increasing heart rate and burning calories.

1. Aquatic Exercises

When standing in waist-deep water, person's weight in water is about 40 percent to 50 percent of what it is on land, thanks to buoyancy. In neck-deep water, body weight is reduced to 10 percent of its weight on land. Water also provides 12 times more resistance than air, making aquatic aerobics highly effective at providing a challenging workout that burns calories and strengthens muscles at the same time, but without the stress on the joints.

Exercises done in water also don't raise the heart rate as much as the equivalent exercise on land. Here are some aquatic exercises to try:

Water walking: In waist- to chest-deep water, walk across the pool swing your arms just like you do on land. Keep your back straight and don't walk on your tip toes. Increase the challenge by wearing webbed gloves that increase the resistance as you move forward.

Water jogging: In waist- to chest-deep water, jog across the pool as fast as you can pumping your arms back and forth energetically. For more of a challenge, kick your knees up as high as you can, or try jogging backward.

Stepping side-to-side: In waist to-chest-deep water, take a big step to the side with your right foot, then bring your left foot in to meet it. Repeat, side-stepping all the way to one end of the pool, then reverse, stepping to the left this time. Increase the challenge by picking up your pace to a skip.

Jumping jacks: In waist- to chest-deep water, jump your legs apart and open your arms out above your head. Then, jump your legs together and bring your arms back down to your sides. Repeat.

Start with a few minutes at a time of each of these exercises. Gradually increase the amount of time spent doing each, until you are exercising for 20 to 30 minutes at a time.

2. Walking

Because of its ease of access, low-impact nature and low risk of injury, walking is another excellent activity for obese adults. Your neighborhood, neighborhood parks, shopping malls and nature trails are all good places to simply go for a walk.

Walking on a treadmill at home or on a gym is another option. Treadmills can provide a more shock-absorbent surface, which can be gentler on the joints. However, the weight capacity of the treadmill should be taken into consideration, as some are not made to support more than 350 pounds.

While walking, pump your arms back and forth. When you feel quite comfortable with walking at a slower pace, experiment with short bouts of faster walking. Alternate a minute or two of fast walking with the same amount of slower walking. Gradual increase the amount of time you spend fast-walking.

Start with short walks and gradually increase the distance or time spent walking.

3. Chair Aerobics

For obese people with injuries or the morbidly obese, chair aerobics provide the opportunity for burning calories without the need to stand or support one's body weight. Chair aerobics are similar to regular aerobics in that they involve doing repetitive rhythmic movements designed to elevate the heart rate.

Here are some chair aerobic exercises to try:

Chair jumping jacks: From a seated position with your arms at your side, open your legs wide, raise your arms and open them wide. Bring you legs back together and return your arms to your side.

Marching legs: Sit slightly forward in your chair. Raise one knee as high as you can, then put it down as you raise the other knee. Pump your arms back and forth or raise them overhead in time with your knees. Increase the pace as you are able.

Lift and twist: Begin seated with your arms crossed over your chest. Extend your right leg out and twist your torso to the right. As you lower your leg, lift your left leg and twist your torso to the left.

Do each exercise for 30 seconds to one minute. Rest, then do another exercises. Perform the exercises in succession, at first for 5 minutes at a time, working up to longer sessions of 20 to 30 minutes. You can also break up the workouts in to three shorter 10-minute workouts throughout the day.