Human Growth Hormone (HGH) – Breaking Down a Few Scientific Studies

July 10, 2009

Increasing natural Human Growth Hormone (HGH) levels in your body is a major key in staying lean year round. It is also a plays a big role in preserving muscle mass when losing those last few pounds of body fat. I’m convinced that anyone can lose weight up to a certain point, but it is that last little bit of fat that takes skill. In my opinion the two biggest fat loss skills to master are to eat in a way that produces a calorie deficit over time & workout in a way that boosts up your levels of HGH and increases that calorie deficit. Another great skill to master is to keep your insulin levels stable, but that is a topic for another post.

human growth hormone hgh

[Here is a picture from 1959 of a group of surfers. Surfers are almost always lean because many of them fast all day out in the surf. Their sport also mixes in short bursts of activity followed by slower steady activity. Does any of this sound familiar? It should because this interval-exercise-and-fasting-combo is a potent way to release HGH! It has been exactly 50 years since this photo was taken and most of these people are in better shape than 90% of gym go’ers today. Has the fitness industry gone backwards?]

You Asked for Scientific Studies and I Found Them

I am a big skeptic most of the time. The whole HGH thing does seem a little “out there”. Unlike lifting a weight and getting stronger the following session…Human Growth Hormone is something that you really can’t measure (well unless you want to get involved with blood tests…no thanks). If I can’t physically see something, I do like to see proof. I don’t need scientific studies for every last detail of my workout, but something major like HGH release…I like to read the available studies.

“Thanks” to All of Those Who Weren’t Scared to Give Blood!

Before I get started, I wanted to personally thank the members of these studies. I hate needles! I’m just not a big fan of getting poked and giving blood. I am sure that I would have turned so pale I would quickly get disqualified. So “thank you” to the people out there who are better with needles than I am!

The Exercise-Induced Growth Hormone Response In Athletes
Brunel University, Uxbridge, Middlesex, UK: 2003

These scientists have completed several studies on exercise and HGH. This paper was a summary of much of their findings. Here are the key points in the summary. Note: EIGR stands for Exercise Induced Growth Hormone Response…basically the HGH that gets released due to exercise.

“The EIGR to endurance exercise is associated with the intensity, duration, frequency and mode of endurance exercise. A number of studies have suggested an intensity ‘threshold’ exists for EIGR. An exercise intensity above lactate threshold and for a minimum of 10 minutes appears to elicit the greatest stimulus to the secretion of hGH. Exercise training above the lactate threshold may amplify the pulsatile release of hGH at rest, increasing 24-hour hGH secretion.”

“Ageing is often associated with a progressive decrease in the volume and, especially, the intensity of exercise. A growing body of evidence suggests that higher intensity exercise is effective in eliciting beneficial health, well-being and training outcomes. In a great many cases, the impact of some of the deleterious effects of ageing could be reduced if exercise focused on promoting the EIGR.”

My Comments: The paper also states that intense anaerobic work raises EIGR as well. So this would apply to lifting as well as body weight exercises if they were intense enough. So this scientific paper explains that you have to get above the lactate threshold to maximize HGH release with exercise…ideally for at least 10 minutes. Does that mean working out hard for 10 minutes straight? Not exactly! Sometimes studies will slightly contradict each other and you have to take into consideration both findings.

The Time Course of the Human Growth Hormone Response to a 6 s and a 30 s Cycle Ergometer Sprint
Dept. of Physical Education, Loughborough University, UK: 2002

This study was comparing 30 second all-out sprints to 6 second all-out sprints. The participants did just one set of this all out-sprint and then HGH levels were monitored closely for 4 hours after the single sprint. Here are some highlights…

“Metabolic responses were greater after the 30 s sprint than after the 6 s sprint. The highest measured mean serum hGH concentrations after the 30 s sprint were more than 450% greater than after the 6 s sprint.”

“Serum hGH also remained elevated for 90-120 min after the 30 s sprint compared with approximately 60 min after the 6 s sprint.”

My Comments: Pretty crazy how just one 30 second sprint can raise HGH levels in a big way. The study also showed that the 30 second sprint raised HGH levels by up to 530% over the resting baseline. I am betting that the reason the 6 second sprint was inferior to the 30 second sprint was that it takes a little longer than 6 seconds to reach lactate threshold. Some say that lactate threshold can be reached in 8-10 seconds, but I am sure it varies from individual to individual (remember lactate threshold is the best way to increase HGH with exercise).

So Why Don’t We Do Just One 30 Second Sprint?

Well, another study has shown that repeated short intervals can further increase the release of HGH…but it a case of the law-of-diminishing-returns. The second sprint produces less of an HGH response compared to the first, the third less than the second, etc. A common intervals routine for fat loss is doing 8 total sprints. You probably don’t need much more if HGH increase is you goal.

Another Reason for Doing Multiple Sprints

Remember HGH release is just part of the fat loss puzzle. We also want to burn calories and take advantage of the fat loss window that HGH creates. HGH helps release the fatty acids from your fat cells into the blood stream. Sprinting followed by a bit of walking is a good way to release the fat and then use that fat for fuel. In some ways doing intervals is like doing an anaerobic and aerobic workout at the same time. I also recommend that you follow intervals up with steady state cardio occasionally…low intensity cardio will help you use up more of the fatty acids that the interval workout has released.

Augmented Growth Hormone (GH) Secretory Burst Frequency and Amplitude Mediate Enhanced GH Secretion During a Two-Day Fast in Normal Men

Dept of Medicine, University of Virginia, Charlottesville: 1992

This study showed that short term fasting could produce 5 times the HGH production in 24 hours compared to eating a typical diet. What the body actually winds up doing is doubling the amount of HGH bursts in that same 24 hour period.

“Two days of fasting induced a 5-fold increase in the 24-h endogenous GH production rate.”

“This enhanced GH production rate was accounted for by 2-fold increases in the number of GH secretory bursts per 24 h.”

My Comments: No need to fast for 2 days straight…that is pushing it. I fast twice per week for 24 hours and it works extremely well. There is a reason that the body produces HGH while fasting…it releases stored body fat for energy, since you don’t have “food energy”…HGH also preserves muscle mass even during this period of time without food.

Effects of GH on Protein Metabolism During Dietary Restriction in Man
Aarhus Kommunehospital, Aarhus, Denmark: 2002

This study proves that you aren’t going to lose muscle all of the sudden if you go 24 hours without food. Most of the fitness world will have you believe that you will lose a bunch of muscle if you don’t “feed your muscles” every few hours. This simply isn’t the case.

“Physiological bursts of GH secretion seem to be of seminal importance for the regulation of protein conservation during fasting. Apart from the possible direct effects of GH on protein dynamics, a number of additional anabolic agents, such as insulin, insulin-like growth factor-I, and free fatty acids (FFAs), are activated.”

“Taken together the effects of GH on protein metabolism seem to include both stimulation of protein synthesis and inhibition of breakdown.”

My Comments: The occasional 18-24 hour fast will actually help you get lean. You have to be strategic and not go overboard, but it will skyrocket your HGH levels…burning fat while sparing muscle.

A Quick HGH Scientific Study Summary (for those who skim)

1) To release maximum HGH through exercise, you need to do intense exercise and aim to reach your Lactate Threshold.

2) One study shows you should aim to stay above the lactate threshold for 10 minutes…another shows a greater than 500% increase in HGH from just one 30 second sprint. I would recommend to do a series of 30 second sprints in interval fashion for 10-15 minutes. This is taking both studies into consideration.

3) The key is to do intense exercise for 30 seconds. Studies show that this can be resistance training. A good 10-15 minute circuit routine or body weight circuit will have the same effect as a sprint interval routine.

4) Make the intense part of your interval longer than 6 seconds. Anything above 8-10 seconds and not too much more than 30-60 seconds will probably suffice.

5) If you want a simple way to increase your HGH by 5 times the normal amount, fast for 24 hours. Don’t go overboard…I have done this for a couple of years now and I find 2 times per week works well.

6) The HGH release during a 24 hour fast insures that you will burn fat and won’t lose muscle.

Note: I couldn’t find studies comparing the effects of injecting HGH vs increasing HGH naturally. Also…there are a ton of studies that I didn’t mention here. I just wanted to talk about studies that dealt with increasing HGH with diet and exercise. One more thing, I decided against doing an article on taking supplements for releasing more HGH. I just feel like it is a waste of your money. If you are really curious…there are countless sites that will sell you their “proven” HGH releasing supplement. Just not my thing.

[Speaking of surfers…watch this video of Laird Hamilton. That wave is insane!]

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Thanks for reading all these years!


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{ 9 comments… read them below or add one }

Norbi July 17, 2009 at 2:38 am


just in general, when / if you want to lose fat, especially those last pounds, then increasing cardio, specifically HIIT cardio would be beneficial in my opinion. Plus try to make sure to do them in a fasted state: try not to eat about 4-5 hours before your HIIT session, and then try not to eat for at least an hour afterwards.

As for your Arizona Diet Green Tea question, it’s funny, cause I’m drinking Lipton’s Diet Green Tea, and just researched if it had anything to do with real tea. In fact it does, but it has aspartame in it, which can have some screwed up side effects. I guess nothing can be perfect. But it’s still a 100 times better than any soda. 🙂

Michael August 26, 2009 at 10:21 pm

Great advice. I am a certified trainer and will try the 30 s sprint system. I am 64 yrs. young and have trained all my life and still fight 2 nights a week. I am sick of all the unknowns in suppliments even though I still use them. Off the pills and on to sprints!! I will keep you posted.

ADRIAN PACE September 17, 2009 at 8:06 am

Hi Rusty
i find your articles interesting but Natural Gh does nothing to the body as does Inj G.H. if it was so people wouldn’t spend thousands on Gh if the effects were the same .
I would like to see real studies on this matter .

Scott December 15, 2009 at 2:43 pm

Injectable Gh does nothing. So im not sure what a 20 min spike during a workout would do.

Leonid January 6, 2010 at 10:45 pm

Hi, Rusty,
I have come across your blog by chance. Very impressive and informative. Thanks for it! A quick question if you don’t mind. What if we substitute fasting with just carb free diet? I mean, completely carb free for 24 hours – HGH is released when sugar levels are low and this can be achieved without fasting. This way, for example, an adaptogene such as Aralia Manchu works – decreasing sugar levels by up to 20 % and thus substantially increasing HGH release. This effect is nothing short of amazing except for ravenous appetite.

Super Scientist September 23, 2011 at 2:39 pm

I went to 3 sixty second sprints in the first mile of a two mile run that I run twice a week. And my testosterone went off the chart. Now I have been experimenting for over twenty years with different workouts in the hope to expand the Life-Span and I believe I am now in the category with the Wright Brothers and Davinci.

I have figured out how and why it works. Penn State studies have told us that three set of 8 to 10 reps in lifting gives the maximum testosterone surge and if you apply this to sprinting it works.

Note, do not, I repete do not do 4 or more sprints. This will cause it to not work.

Peter Griffin February 28, 2013 at 4:48 pm

Got here through google. Great article. Thank you

shaun March 26, 2013 at 11:04 am

“A good 10-15 minute circuit routine or body weight circuit will have the same effect as a sprint interval routine.”

— No freakin’ way, dude. June 1, 2013 at 2:52 pm

After you turn 35, your body slows down production of growth hormones.

It really is amazing that these supplements, paired with
a healthy and active lifestyle, are able to help men to enjoy a much higher quality
of life. It is required throughout our life to maintain and carry on regular
functions in our body.

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