I think most people have a few choices of Cardio Equipment when going to a box gym such as LA Fitness, which I frequent. My preferences are as follows:

1) Elliptical Trainers: Specifically, the Precor EFX546i which has a program that I like to try and get good cardio burn, high HR & hopefully some HGH release, the 2 Minute interval training program.

2) Treadmills: It does seem that the exercise of choice for the truly fit <15% BF is jogging. With 39% BF, my knees can't take it yet, but I'm working on it, 2 Osteo-Bioflex a day

3) Cycles: These machines don't do anything for me

4) Stair climbers: I see people doing odd activities on these, walking sideways, sometimes backwards, as if they're all in some program I'm wholly unaware of to make your glutes look young or something

5) Stair Masters: No one uses these machines, maybe one person a day

6) Rowing Machines: These are the death of me, one day I want to be able to hit the gym, push weights for 15 minutes than row for 20, pacing fast and slow with each 1 minute change... maybe in 6 months

My question is basically which of the above do you use and prefer and why? What's the science behind the preference if I may ask, because it seems the Elliptical almost sometimes seem too good to be true.

My most recent routine was 45 minutes, which said that based on my weight & age, I burned 665 calories, but I push myself hard, usually averaging 150 rpms. I've been doing this type of long push cardio for the first time in my life and so far love the energy burst of the second half, when with no carb loading or other unnecessary dietary interferences, my body naturally releases the right hormones to promote fats burn and give me greater strength, stamina, and recovery than the first half usually. Getting to the 1/2 part is harder than finishing sometimes it seems...

What's your preference?

I've just recently read that the recumbant bicycle is also a good cardio machine.
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I've also recently read that if you are short on time a 20 minute workout on any of the cardio machines consisting of a type of interval training - can have very beneficial results.
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2 min warm up
30 sec high intensity pace
90 sec recovery pace
repeat 30 sec - 90 sec for 7 more cycles for a total of 8 30/90 cycles
2 min cool down
= 20 minutes.
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I will try and find the article for this.
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I have yet to try it since seeing it, since I was in my full, once a week, 1 hour, weight resistance circuit yesterday.
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However, I might give it a try on Wednesday, after I meet with my scheduled personal trainer.
(It was a special at out local YMCA, Five 1/2 hour sessions for $40 - couldn't pass it up, though we need to be frugal, this was worth it, and I learned a lot.)

Interval training and Interval cardio as you described have been shown to increase HGH release 15-20 minutes after workout and at night, and natural HGH releases are an excellent way to improve health. I was reading up on that in the Anti-Aging Zone two nights ago under fitness.

Interestingly, 45 minutes is the tops that Dr. Sears placed on Anerobic exercise because of the catabolic response after 45 minutes of intense work out by the muscles.

Are You in Somatopause (Age Related Growth Hormone Deficiency?)

As you reach your 30s and beyond, you enter what's called "somatopause," when your levels of HGH begin to drop off quite dramatically. This is part of what drives your aging process.  It has been my experience that nearly everyone over 30 has dramatically abnormal levels of this important hormone because they begin leading increasingly more sedentary life styles.  Children and most animals in the wild do not run marathons or lift weights, they move at high speeds for very short periods of time and then rest. This is natural and what optimizes the production of growth hormone.

The higher your levels of growth hormone, the healthier and stronger you're going to be. And the longer you can keep your body producing higher levels of HGH, the longer you will experience robust health and strength.  Dr. Harvey Cushing discovered HGH in the form of somatotropin almost a hundred years ago.  Many individuals choose to inject it, though it is a banned substance in many professional sports. 

As I said earlier, I don't recommend doing this as I believe the health risks and cost are in no way justifiable.  Ideally, you really want your body to produce it naturally, as injecting HGH does have side effects. And the way you produce it is by exercising your super-fast muscle fibers.

Benefits of Peak Fitness Exercises

Minimally, once you regularly participate in these 20 minute excises about twice a week, most everyone notices the following benefits:

• Lowers your body fat
• Dramatically improves muscle tone
• Firms your skin and reduces wrinkles
• Boosts your energy and sexual desire
• Improves athletic speed and performance
• Allows you to achieve your fitness goals much faster

How to Properly Perform Peak Fitness Exercises to Increase Your Growth Hormone Levels

First of all, please remember that you can perform this with any type of exercise. While having access to a gym or exercise equipment will provide you with a larger variety of options, you don't require either. You can easily perform this by walking or running on flat ground.  You will certainly want to work your way up to this point, but ultimately you want to exercise vigorously enough so you reach your anaerobic threshold as this is where the "magic" happens that will trigger your growth hormone release.

Whatever activity you choose, by the end of your 30 second period you will want to reach these markers: 

• It will be relatively hard to breathe and talk because you are in oxygen debt
• You will start to sweat profusely. Typically this is occurs in the second or third repetition unless you have a thyroid issue and don't sweat much normally.
• Your body temperature will rise
• Lactic acid increases and you will feel a muscle "burn"

If you are using cardio equipment like an elliptical or bike, you don't need to reach any "magical" speed. It's highly individual, based on your current level of fitness. But you know you're doing it right when you're exerting yourself to the point of typically gasping for breath, after a short burst of activity.

An added boon is that you'll save a tremendous amount of time because peak fitness will cut your hour-long cardio workout down to a total of 20 minutes or so, including your recovery time, warm-up and cool down.

The actual sprinting totals only 4 minutes!

Here's what a typical peak fitness routine might look like using a recumbent bike:

1. Warm up for three minutes
2. Exercise as hard and fast as you can for 30 seconds. You should feel like you couldn't possibly go on another few seconds
3. Recover for 90 seconds
4. Repeat the high intensity exercise and recovery 7 more times

Be mindful of your current fitness level and don't overdo it when you first start out. If you are not in great shape and just starting this you may want to start with just two or three repetitions, and work your way up to eight, which is where the magic really starts to happen. You may need to start with just walking and when you do your 30 second bursts your legs would be moving as fast as possible without running - and your arms would be pumping hard and fast.

If you can do a peak fitness workout twice a week, and follow the dietary recommendations I'll go over next, you will increase your production of growth hormone.

Dietary Recommendations to Maximize Growth Hormone Release

To maximize your growth hormone release you need to:

• Get a good night's sleep
• Avoid a high fat meal prior to exercising
• Drink plenty of water
• Eat healthy carbs (think vegetables) and high quality protein
• Optimize your vitamin D levels
• Avoid sugar, especially fructose

The last part is absolutely crucial.

If you consume sugar or fructose, especially within two hours post-exercise, you will increase somatostatin which will in turn obliterate the production of growth hormone!  This is yet another example of why gulping down sports drinks that are chockfull of high fructose corn syrup can do your body more harm than good, and will just shut down your body's production of HGH and negate many of the benefits from your exercise.

John that's an excellent article. I hope everyone here has a chance to read this. It's a proven method to get the most out of a workout in the shortest amount of time.

My current plan is to exercise in Intervals for 45 minutes a day - 6 days a week, with weights/cardio on 3 and cardio only on 3. I find that this type of exercise usually leaves me with more energy than when I start, with a clearer head, better circulation and improved hydration because I usually take in 24oz + of water in 45 minutes on the eliptical.

I think it all adds up to a higher metabolism and functioning HGH / IGF1 system causing some moderate muscle growth and fat burn as a long term result of healthier growing LBM.