Power Walking
A convenient and easy aerobic exercise that everyone should do. The risk of injury is quite low, it's convenient (you can perform outside or on a treadmill) and can be highly aerobic if performed properly.

A highly aerobic activity that can produce quicker weight loss results. Jogging may not be ideal for beginners or those who are quite overweight or have heart problems. Check with your physician before you begin a jogging routine.

Aerobic Dancing
It seems every week gyms come out with a new low-impact aerobic dance class. Most are hybrids that blend dancing with sport movements like kickboxing, martial arts and even yoga. Best of all: most are ideal for any fitness level.

Slightly different than stair-stepping, stair-climbing is performed on actual stairs, like those found in your home or in a stadium. No stairs around? Many gyms now have reintroduced escalator-like machines that mimic traditional stair-climbing.

The following exercises are not quite as aerobic as those above, but still offer solid workouts.

Stair-stepping requires the use of a stair-stepping machine where your legs move in an up-and-down motion, like you're climbing stairs, but without having to take actual steps. It's an ideal alternative to stair-climbing for those with some physical limitations, like tricky knees or low fitness levels, as it places less stress on the body.

Elliptical Exercise
A combination between jogging and stair-stepping, it's an ideal replacement for those who have difficulty with weight-bearing exercises because it doesn't overly stress muscles and joints. For an all-around workout, use an elliptical exercise machine that simultaneously moves both your arms and legs.

Incline trainer
Incline trainers are hybrid machines that fall somewhere between stair-stepping and walking. They look and act like a high-performance treadmill, but allow for an up to 50 percent incline for high-calorie burning in a shorter amount of time.

An exciting way to enjoy a group workout in a gym without having to worry about keeping up or following specific steps or routines. Just take a seat and start pedaling at your own pace. Want some fresh air and sun? Get the same workout with regular outdoor cycling…just keep the coasting to a minimum.

Indoor Rowing
This is a fairly aerobic exercise that's easy to learn and also conditions your arms and legs. It's ideal for all fitness levels, although people with back or neck ailments should avoid.
As a reminder, always consult your doctor for medical advice and treatment before starting any program.