As a personal trainer I have tried day after day to get clients to do cardio so they can reach their weight loss goals more quickly. I've had every type of client: The one who comes a minute before their session and thinks that 1 minute spent on the bike counts as a warm-up; The client who does the 5 minute warm-up and thinks that should be enough cardio for the day; The client who walks at 2 miles per hour on the treadmill for 15 minutes and thinks she should be losing more weight because of it. The list could go on, but I won't.

Cardiovascular or aerobic exercise for weight loss takes a lot more effort than those listed above. You don't have to do one specific type of aerobic exercise all the time but you do need to work at a higher intensity, especially if you want to lose weight an an appropriate pace. I will give you some tips for your cardio workouts:

1. 1. Get out of the Fat-burning Zone! I wish the machines would stop coming with this heart rate zone setting. Working at the heart rate zone for fat burning according to the machine will have you moving so slowly you probably won't break a sweat or get your heart pumping much out of the 120's (beats per minute). To lose weight you need to burn calories and to burn calories you need to work harder. So pick up that pace, get out of the fat-burning zone and watch the pounds come off more quickly.
2. 2. Do Interval Training. You can work at higher intensities than you normally would be comfortable by alternating the high intensity with low intensity. For example: Walk for 2 minutes, run for 30 seconds and then walk for 2 minutes and repeat this cycle. You can follow the same principles on the bike, elliptical, etc. Vary the speed and resistance to challenge your body and go to the low levels to allow your body to recover.
3. 3. Switch up your mode of cardio. Always doing the same activity becomes easier for your body and therefore you won't burn as many calories. Constantly switch up the type of cardio activity you do and the style you do. Do intervals on the treadmill one day; Swim in the pool another day; Use the elliptical at a moderate-intensity steady state pace, and so on.

To lose one pound of body fat you need to burn 3,500 calories more than you usually do. If you are aiming to lose one pound per week through exercise you need to increase your cardio time and intensity. Many times a combination of diet and exercise will allow you to lose weight more quickly.