Duration of Aerobic Exercise – The Length of Cardio Workout

Written by Yasar Shahzad Wednesday, 07 July 2010 19:17

Duration of Aerobic Exercise – The Length of Cardio Workout

The longer you work out, the more calories you’ll burn and the more calories you burn, the more fat you'll lose. Makes sense, right? Of course, this only applies if your intensity is high enough. A long workout (30 minutes or more continuously) with an extremely low intensity won’t burn enough calories to have any impact on fat loss. There’s a minimum intensity threshold you must cross to get maximum benefit from each workout and you’ll learn about this “fat burning intensity zone” later in this section. Another reason you burn more fats with a longer workout is because you tend to favor the use of glycogen early in the workout, and then as your glycogen becomes depleted, stored body fat becomes the primary fuel source.

Cardiovascular health benefits, such as decreased blood pressure, decreased blood cholesterol, lowered resting heart rate and increased aerobic capacity can be achieved with as little as 12-20 minutes of cardiovascular activity. However, if you stop after only 20 minutes, you’re not burning enough total calories to have much impact on fat loss.

Most body types need to do aerobic exercise continuously for at least 30 minutes to burn a substantial amount of fat. Thirty to forty-five minutes continuously per session is the recommended duration for your goal of fat loss. Sixty minutes should be the maximum. Beyond 60 minutes per session, you tend to reach a point of diminishing returns and increase the likelihood of injury, over-training and adaptation. If you’re stuck at a plateau and you wish to do more than 60 minutes per day, you can, but it would be best to split it into multiple sessions, for example; 30-45 minutes in the morning and 30-45 minutes at night.
If you’re limited in time and long 30-60 minute cardio sessions are not an option, then it would be most productive to increase the intensity of the time you do have to maximize the calorie burning effects. This way, a 15-25 minute aerobic session can produce a substantial expenditure of calories.

Why are there so many programs recommending short cardio workouts?

One very popular fitness author claims that twenty minutes of aerobics three times a week is the “solution.” A supplement company owner claims that sixteen minutes of high intensity aerobics is the optimal duration. Yet another “fitness guru” says that eight minutes in the morning is all it takes.

If I’m right, and a 30 to 45 minute cardio session is the most effective way to train for fat loss, then why do so many “gurus” in the books and on TV talk about these “super-short, super- easy” aerobic workouts? The answer is simple: “Quick and easy” sells, “Long and difficult doesn’t sell. It’s all about marketing and the almighty dollar. If an author or promoter of a product can convince you that you can achieve your dreams with a minimum of effort, their sales will skyrocket. A wise person knows nothing good ever comes fast and easy.

Getting in great shape by spending only twenty minutes a day, three days a week (or less!) sounds great, but when things sound too good to be true, they usually are. If your goal is better health and a decent level of cardiovascular fitness, then three days of cardio a week for 20 minutes IS all you need. However, if your goal is to lose a lot of body fat as quickly as possible, then you're probably going to need more than 20 minutes.

If you're one of the few people genetically blessed with a fast metabolism and the ability to burn fat easily, then three days a week for twenty minutes will work for you. In fact, I know a few people with hyperactive metabolisms that stay ripped all year round without doing any cardio at all! Not many of us are that fortunate. I've seen very few people lose fat quickly from just three days a week of cardio. On the other hand, I’ve never seen anyone do six days a week of cardio for 45 minutes and NOT lose a lot of body fat (provided of course, they were on a good diet).

If you have superior genetics, you might get away with very little cardio. But if you’re like most people, be prepared to do more. The bottom line is that you should do as much - or as little - cardio as it takes for YOU to reach your goal. You can only determine how much that is by understanding your body type, getting started and adjusting your program through trial and error. If you can lose fat from just three 20 minute workouts a week - that's GREAT! Don't do more if you don't have to. However, if you've been doing 20-minute workouts three times per week and nothing is happening, then you need to increase your duration and/or frequency until the fat starts coming off.

Duration Guidelines for Aerobic Exercise

Here’s a summary of the duration guidelines for your cardio workouts while your goal is building lean muscles and losing maximum fats:

When your goal is maximum fat loss: 30-60 minutes of continuous activity per session
When your goal is gaining muscle, maintenance or cardiovascular conditioning: 20-30 minutes of continuous activity per session

Frequency of aerobic exercise (How often should you do cardio?)

The number of days per week you do aerobic workouts is largely dependent on your goals. Everyone should always do three days per week of cardiovascular work as a minimum. Three days of cardio a week is a habit you should maintain as a part of your lifestyle for your health if no other reason. If your body fat is already in the desirable range, then three or four 20 to 30 minute workouts per week are usually enough to maintain your low body fat level and stay aerobically fit. It’s also enough to help keep you lean when you’re working on gaining body weight. If your goal is to lose body fat, then adding a fifth, sixth or seventh day will maximize your results.