When you're trying to slim down, the goal is to lose fat, not muscle. To do so, you need to do a combination of cardio and resistance-training exercises. While most types of cardio can help you increase your daily calorie burn and lose weight, some may help you do so a little faster than others. Don't forget that while exercising more often may help you lose weight, you'll get faster results if you also make dietary changes, such as eating 500 to 1,000 fewer calories per day. Be sure to check with your doctor before starting a new diet or exercise plan to make sure it is safe for you.
Cardio for Fat Loss
The basics of weight loss are simple; you need to burn more calories than you eat. Cardio exercises, such as swimming, running, walking and dancing, help you burn more calories. The longer and more intensely you work out, the more weight you will lose and the greater improvements you will see in your body composition, according to a study published in Archives of Internal Medicine in 2004. Aim for at least 300 minutes per week of moderate-intensity cardio or 150 minutes per week of vigorous cardio. You're working out at a moderate intensity if you can talk but not sing, and once you can no longer hold a conversation with your workout buddy, you've moved into vigorous exercise.
Although lifting weights doesn't burn as many calories as cardio, you still should not leave lifting out of your workout routine. If you don't include this type of workout, about one-fourth of any weight you lose is going to come from muscle instead of fat, according to the American Council on Exercise, and may slow down your metabolism. Try to fit in resistance-training workouts at least twice a week when you're trying to slim down. Include exercises that target each of the major muscle groups, such as arms, shoulders, chest, back, abdominals and legs.
High-Intensity Interval Training
High-intensity interval training, or HIIT, mixes bursts of high-intensity cardio with lower-intensity cardio intervals for recovery instead of the typical cardio workout during which you spend the entire time working out at a more moderate-intensity level. With HIIT, you can get a lot of benefits with a shorter workout, but it isn't recommended that you do high-intensity interval training more than once or twice a week for about six weeks, or you could increase your risk of injury. This type of workout may be better at decreasing body fat than regular cardio, notes a review article published in the Journal of Obesity in 2011. For example, doing seven high-intensity interval training workouts over the course of two weeks helped women increase fat burning during exercise, according to a study published in the Journal of Applied Physiology in 2007.
Circuit Training for Fat Loss
Circuit training, workouts that usually include a mix of resistance training and cardio exercises, also may help you burn fat more quickly. You typically perform one to two sets of a resistance-training exercise, then between 30 seconds and 3 minutes of cardio and repeat until you've gone through all of the exercise stations in the circuit-training workout. This type of workout may help you lose more weight and more body fat than simply spending your entire workout doing cardio. People who did high-intensity circuit training three days per week for 50 minutes for 12 weeks had greater improvements in their body composition than those who did low-intensity circuit training or a cardio-endurance workout for the same amount of time in a study published in The Journal of Sports Medicine and Physical Fitness in 2010.