can high-intensity interval cardio really work for fat-loss?

[ascendant]

just wanted to get peoples personal experiences on the subject. i'm talking the kind of cardio where you do like a low-intensity for a min or two, then high intensity for a min or two, then back and forth. my issue is that by doing the high intensity, your body will want to tap into muscle protein as an energy source rather than fat, but i know that the high-intensity cardio will keep your metabolism up for longer than staying in a fat-burning range.

i know the whole high/low intensity cardio to burn fat thing is very controversial, but wanted to see if anyone had any personal experiences using interval cardio training they could share? NOW ONE IMPORTANT PREREQUISITE BEFORE POSTING YOUR EXPERIENCES... i ONLY want to hear experiences from people who kept track of their bodyfat percentage AS WELL AS their lean mass. i don't care if you lost more weight doing interval training as opposed to lower-end cardio in the fat-burn zone. i want to actually see people say they lost just as much if not more fat doing interval training as opposed to more moderate fat-burning cardio training AND maintained their muscle mass in the process. my main concern here for interval training is whether or not it will burn away at muscle, so if you don't have that info, don't bother posting please as that's my one and only focus here. thanks.

[Machdiesel]

I tried something like this, and it worked EXTREMLY well!!!! It wasnt very scientific, and i came up with it myself so it may be COMPLETLYwrong,but it worked . my theory was that if i threw in a few running spirts inbetween my fat loss power walk it would keep my heartrate up during the entire workout and burn more cals/fat, heres what i did

Walk at 4.1 for 10 minutes
Jog at 5.0 for 5 minutes
walk at 4.1 for 10 minutes
jog at 5.0 for 5 minutes
walk at 4.1 for 10 minutes
Joj at 5.0 for 2 minutes
then 8 more minutes at 4.1

[Machdiesel]

This worked much better then me just doing the usual 50 minutes in your "fat burning" heart rate zone. But i guess it makes sense, the faster u go, the higher ur heartrate, the more fat u lose. Of course most people on here like keeping their heart rate alittle lower because they are trying to bulk. ME personally i like to throw alittle joggin in, it makes me feel like im gettting a good cardio workout, and staying healthier, as opposed to just walking. For neone here who are runners, i would gladly give up a few pounds for the runners "high" you get after every workout

[wakatak87]

mach...what does 4.1 and 5.1 mean...

and to the OP, i know this site has long been for 60-70% MHR for 40-60 minutes, but im starting to think interval training IS the way to go. several studies have been done to show this. i want to try it but i dont know exactly how to DO interval training despite all the pages ive read on google and such. wikipedia suggests sprinting somewhere...then walking back so the starting point and doing it again. which sounds like sprinting for x minutes then walking for 4x minutes. anyway...im very interested in the subject as well.

[Machdiesel]

4.1 and 5.0 is the speed on the treadmill in MPH

[Machdiesel]

most interval training has short bursts of sprinting then walking or jogging, but when on a treadmill its tough(and annoying) to change speeds ever minute for 45 mins, so i modified it to what i posted above, as i said its not perfect,but was great for me

[wakatak87]

how long should one sprint for and how long should they rest for though? does my 4x formula work? so like, 30 secs of sprinting followed by 2 mins walk?

[abbot138]

This worked much better then me just doing the usual 50 minutes in your "fat burning" heart rate zone. But i guess it makes sense, the faster u go, the higher ur heartrate, the more fat u lose. Of course most people on here like keeping their heart rate alittle lower because they are trying to bulk. ME personally i like to throw alittle joggin in, it makes me feel like im gettting a good cardio workout, and staying healthier, as opposed to just walking. For neone here who are runners, i would gladly give up a few pounds for the runners "high" you get after every workout

I agree with you on the runners high, its nice to get done with cardio and actually feell like you did something. However, the reason most people on here prefer to stay in the "fat burning zone" is that when you go into the anaerobic zone your body goes into panic mode and looks for the easist sources of fuel to burn i.e.- sugar and then muscle. So by getting out of this zone your not only burning fat you are also burning muscle. Endurance cardio is the best way to burn fat and fat only.

[wakatak87]

abbot, why does the body choose to burn muscle over fat, when muscle is more useful to the body?

although i also heard that the muscle burned during cardio is negligible

[abbot138]

abbot, why does the body choose to burn muscle over fat, when muscle is more useful to the body?

although i also heard that the muscle burned during cardio is negligible

It burns the muscle because it looks for the easiest fuel to burn(which is sugar and muscle)....It can be negligible it depends on how long you stay in that anaerobic zone. I'm not sayin dont ever let your body go into that 85% plus zone, I'm just saying dont do it for 45 minutes at a time. I love doin srpints, there a great way to build strength, I just think the best way to assure that you are only burning fat is to stay in the endurance cardio zone.

[Expat]

When you honestly do not have time for a full blown workout, try interval training. Speedwork or short sprints can replace long slow distance workouts. Spend five minutes warming up at an easy pace. Then gradually increase your intensity until you are moving at about seventy percent of your maximum speed. You may feel a slight burn in your legs. And your lungs may open up for the first time in years. Hold this pace for about a minute. Then slow down to your normal tempo for two minutes. Increase your speed again to seventy percent for another leg exploding, lung expanding, minute. Cool down to a relaxed pace for another five.
Use intervals for walking, running, cycling, or in-line skating. The faster, more intense, velocity may be uncomfortable at first. Your heart rate and breathing will skyrocket. Soon you will crave it. Add one/one minute interval each week until you are sprinting a maximum of ten/one minute cycles. If you do not relish watching the clock, simply speed up between telephone poles. Then slow to your normal rate until you reach the next pole. Interval training burns fat, builds endurance, speed, and recovery. You will complete your workout sooner, and it is a pleasant
diversion from your long, slow, distance stroll.
Interval training is varying your intensity throughout your exercise session. Alternate high-intensity work bouts and low-intensity rest periods. Intervals are used to improve your performance using effort intervals followed by recovery intervals. You can make interval training specific to your sport. Or you can use intervals to improve your fitness. To begin, make intervals equal to your normal steady state program. Follow this with a rest/recovery segment performed at a lower intensity.
Research has shown that interval training improves both your aerobic and anaerobic capacity. Continuous, long, slow, distance training improves aerobic capacity only.
Interval training has also been shown to burn more total fat and calories than continuous training. Intervals allow you to perform more work increasing your Excess Post Oxygen Consumption (EPOC). EPOC, the "afterburn", is the absolute number of calories you consume, long after you have completed your workout.
Intervals have the potential to train your heart muscle longer and more effectively than a single bout of continuous training. During interval training, your heart must overcome a greater resistance. This leads to improved venous return which results in greater ventricular
filling and contractility. You experience a more complete emptying which increases your stroke volume and cardiac output.
Interval training also improves your muscle's ability to tolerate lactic acid. You become accustomed to short periods of training, just below your anaerobic threshold. This helps you learn to delay the onset of fatigue.
An interval training program (aerobic system) is low intensity but
continues for longer than three minutes. Both the work and rest intervals occur at an intensity that is within your aerobic system. The interval period is performed at a slightly higher intensity than your steady state. The rest period is slightly lower than your steady state. The time in each interval usually ranges anywhere from 4 to 15 minutes.Climb on your exercise bicycle. Warm up for 3 minutes. Pedal at 70 percent of your maximum for 5 minutes. Take a one-minute easy-pedaling break. Perform another 5 minute interval.
An advanced interval training program (ATP-PC) is very high intensity, and short in duration (1-15 seconds). Sprint or lift weights at 95 percent intensity for 15 seconds. Then take a 45 second break. Your recovery interval is absolute-rest to allow for replacement of ATP and creatine phosphate. Because your work/rest cycle is relatively short, you can repeat the cycle 10 - 20 times within a single workout.
Another advanced interval training program (lactic acid system) kicks in at a high intensity and short duration (45-90 seconds). The work interval is greater than your anaerobic threshold. After your warm up, run the length of a track at 65 percent of your maximum speed. Jog slowly around the curve. Your rest interval occurs in the aerobic system. Use this program if you are highly fit and athletic. Your rest interval is active recovery. This allows for removal of lactic acid.
Speedplay is a form of interval training that is based on how you feel. It is less systematized than normal intervals. You govern how hard you want to work. You control your intensity based on your tolerance. Speedplay may be more enjoyable than timed intervals. It teaches novices how to progress beyond their anaerobic threshold. They learn to subjectively rate their perceived exertion.
Interval SportCord training may be performed on a circuit. Perform 1 set of 10 repetitions at 60 percent of your maximum. Take about 30 seconds to finish each exercise. Your rest interval is the period between exercises. Recovery time is minimal, as it includes only the seconds required to strap into the next machine. Your goal is to complete 10 repetitions on all 12 machines with limited rest between sets.
A variation of circuit weight training is aerobic circuit training. Aerobic circuit training is simply adding a 30 second to 3 minute aerobics station between each weight set.
The benefits of interval training include:

1. Increasing your VO2 maximum. You will also be able to work out at a higher percentage of your VO2 max. because you will increase your anaerobic threshold.

2. You can burn more total fat and calories in a shorter workout session thereby maximizing the use of your time.

3. You will be effectively stimulating both fast and slow twitch muscle fibers.

4. You can change your interval routine to avoid overuse injuries. 5. Long, slow, continuous training sometimes becomes boring. Intervals spice up your program.








Interval training has been the basis for athletic training routines for years. The first forms of interval training, called 'fartlek' involved alternating short, fast bursts of intensive exercise with slow, easy activity. Fartlek was casual, unstructured training that perfectly fit it's english translation: "speed play."

Interval training works both the aerobic and the anaerobic system. During the high intensity effort the anaerobic system uses the energy stored in the muscles (glycogen) for short bursts of activity. Anaerobic metabolism works without oxygen. The by-product is lactic acid, which is related to the burning sensation felt in the muscles during high intensity efforts. During the high intensity interval, lactic acid builds and the athlete enters oxygen debt. During the recovery phase the heart and lungs work together to 'pay back' this oxygen debt and break down the lactic acid. It is in this phase that the aerobic system is in control, using oxygen to convert stored carbohydrates into energy.

This repetitive form of training leads to the adaptation response. The body begins to build new capillaries, and is better able to take in and deliver oxygen to the working muscles. Muscles develop a higher tolerance to the build-up of lactate, and the heart muscle is strengthened. These changes result in improved performance particularly within the cardiovascular system.

Interval training also helps prevent the injuries often associated with repetitive endurance exercise, and they allow you to increase your training intensity without overtraining or burn-out. In this way, adding intervals to your workout routine is a good way to cross train.


According to the American College of Sports Medicine, more calories are burned in short, high intensity exercise. If you are counting calories burned, high intensity exercise, such as intervals, beats long, slow endurance exercise hands down - but you may pay a price. Read more about the benefits and dangers of high intensity exercise.

You don't need to be a world-class athlete and have sophistocated blood analysis to take advantage of the benefits of interval training. The standard 'speed play' training of fartlek works well for the rest of us. This type of interval work is based upon your subjective needs. Simply pay attention to how you feel and set your intensity and duration accordingly.

Precautions for Safe Interval Training

Warm Up before starting intervals
Assess current conditiong and set training goals that are within your ability
Start slowly. (for example: walk 2 minutes/ run 2 minutes) In general, longer intervals provide better results
Keep a steady, but challenging pace throughout the interval
Build the number of repetitions over time
Bring your heart rate down to 100-110 bpm during the rest interval
To improve, increase intensity or duration, but not both at the same time
Make any changes slowly over a period of time
Train on a smooth, flat surface to ensure even effort
You can also use circuit training as a form of interval training
Advanced Interval Training
You can take a more scientific approach to interval training by varying your work and recovery intervals based on your pre-determined goals. Here are the four variables you can manipulate when designing your interval training program:

Intensity (speed) of work interval
Duration (distance or time) of work interval
Duration of rest or recovery interval
Number of repetitions of each interval

[ascendant]

the majority of you guys seemed to overlook my main focus, which was were you able to do interval training and NOT lose muscle AND burn more bodyfat that way? i know how interval training works, and that's NOT what i intended this thread for. i'm ONLY looking for personal experience that someone can tell me they did interval training, burned more fat than training in the cardio zone, and DIDN'T lose muscle in the process either. that's all.

i appreciate your input machdiesel, but from what you wrote you seemed to indicate at one point that you lost some muscle as well but you thought it was worth the sacrifice. i certainly don't considering 1lb of muscle will burn about an extra 50 cals/day. you lose muscle, you burn less calories, so it certainly is not beneficial to me in any way to lose any muscle.