March 06, 2011
Tiger Blood And Neuropeptide Y: Calm Under Fire

A Slate article took Charlie Sheen's (very entertaining IMO) comments about his tiger blood as an occasion to look at the science behind people who can respond very calmly and adaptively when in danger and under pressure.

Yale psychiatrist Andy Morgan, for example, has studied elite Special Forces recruits as they undergo "Survival, Evasion, Resistance, and Escape" training, a three-week course designed to simulate the tortures of enemy capture. The program is brutally stressful, yet many recruits preserve an amazing amount of mental clarity in the midst of it. When Morgan examined the poised trainees' blood tests, he saw that they were producing significantly more of "a goofy little peptide called neuropeptide Y" than other, more rattled recruits. The extra NPY was like a layer of stress-deflecting mental Kevlar; its effects are so pronounced that Morgan can tell whether a soldier has made it into the Special Forces or not just by looking at a blood test.

I've long argued that we will see the development of drugs that allow us to customize our minds and bodies to different work environments, home environments, and other conditions. Shift into hyperfocus mode, shift into social conversational mode, and other states of mind as needed. One can see why militaries would want this capability. Turn soldiers into calm functioning machines when they go onto the battlefield. When first entering a dangerous battle avoid having a significant percentages of soldiers either totally crack and run or become paralyzed zombies.

Turns out this is not new news. A 2004 report finds special forces have more NPY than normal soldiers.

Special forces soldiers, who had thirty-three percent higher plasma levels of neuropeptide Y than general troop soldiers, were found to possess clearer minds and to have out-performed other soldiers under stress. In a related study, Morgan and colleagues also discovered that soldiers in Combat Dive training who released more NPY during stress excelled in underwater navigation, and that hostage rescue team members with higher NPY levels during stress performed better.

Whether the Special Forces guys developed the ability to respond better to stress or have that as an innate ability is not clear. Though my guess is more the latter.Special Forces also have their NPY drop faster after a stressful situation. So they adjust more rapidly both to stressful and normal situations. They aren't called "special" for nothing.

Alterations in how our minds and bodies respond come with costs. Some evidence suggested that genetic alleles (variations) that boost NPY levels also boost atherosclerosis risk. So does calm under fire really mean that the stress is just taking a different kind of toll on your body? I am surprised by that result because other reports claim NPY reduces the stress response. Though another report found NPY injection causes obesity in female rats.

Once scientists develop a much clearer and far more detailed picture of stress response pathways it will become possible to tweak hormones and other biochemicals to fine tune our metabolic and cognitive responses to a great many environments and conditions.

Share |      Randall Parker, 2011 March 06 09:49 PM  Brain Emotion Alteration

Lono said at March 7, 2011 8:25 AM:

It seems likely I may have this condition.

I was a little disappointed to find that my children do not seem to have this same disposition but such is the way of things.

I have been clinically diagnosed with ADD, OCD, and addictive personality disorder and am likely to have lower levels of dopamine receptors than most which is likely why I have often sought out excess stimulation such as extreme sports, ultra-violent video games, and frequent use of psychedelics, alcohol, and for a brief time cocaine.

I had always assumed it was my ADD that caused my calm under duress - with my tendency to hyper-focus at times - but I would be interested in taking this blood test to see if I have an above average amount of this peptide.

I also have what seems to be an unusual ability to pretty much will a large surge of adrenaline whenever I want to - although I rarely engage anyone in hand to hand combat largely because I worry that I enjoy this feeling a little too much. I wonder if this ability is common amongst those who have an excess of neuropeptide Y?

(I've yet to meet any other athletes or weight-lifters who know what I am talking about concerning this - maybe it's a Viking thing)

Anyone else here relate to this ability or exhibit unusual calm under pressure?

Axel said at March 8, 2011 6:32 AM:

Quite interesting.

@Lono how do you respond to stimulants?. Coffee, Ritalin?. Thanks

Axel said at March 8, 2011 6:41 AM:

Randall, please consider a social button so we can post links to Twitter, Facebook, etc. e.g.

Lono said at March 8, 2011 7:58 AM:


It's funny - I have a fairly low tolerance for coffee - although I do drink it most days now.

(usually heavily diluted - and I didn't start until my late twenties - although I had used caffeine pills occasionally in high school to try and amp up my workouts)

Ritalin was frankly a bizarre experience for me - because I took it three or four times in college - the first time after drinking heavily - and all three or four times - after several hours - I experienced a taste of what it must be like to be agoraphobic - and it was honestly my first taste of what it is to feel true fear.

And I took a fairly small dose each time.

It reminded me of that scene in Eric the Viking where they are entering into Valhalla - and the berserker in the group is like - I don't feel quite right - because it was not until he was face to face with the Gods that he had anything that approached a paralyzing type of fear.

Now - like the people in the article - I do fear sub-optimal outcomes - and I can get awkward physiologically if it has been a long time since I last spoke before a large audience - but I just don't panic - I focus - I enjoy the rush - the awkwardness of it all - the adrenaline - the challenge.

Boredom or waiting for long extended periods - to me - is the real torture - I'm sure I'd break after just a couple days in the hole if I had no stimulus - but it would be hard to break me through physical pain - I don't particularly like the idea of having my eyes drilled out though - but who really does.

To feel the paralyzing fear that many normal people feel was a painful, humiliating, depressing, experience for me and I would never choose to feel that way again.

However I have to be careful to not go Dexter either - because I can vividly imagine the rush of removing true sociopaths/psychopaths from the gene pool - but I am far too empathetic to likely ever do so in real life.

Where are those dang holodecks when you need them!? Getting closer every day I presume...

_Jon said at March 8, 2011 11:58 AM:

In the other direction, I wonder if chemicals to disrupt this ability are in development.
- When seeking to get information from a prisoner, an injection of a chemical to suppress NPY might be beneficial.
- When facing an army on a battlefield, spraying or diffusing a such a chemical to reduce focus or increase stress would also help.
-- Or when facing hostile protesters, for that matter.

(I'm not endorsing these uses, just speculating on their effectiveness.)

TB said at March 8, 2011 12:26 PM:

What do they say about people who run around screeching for a while under a crisis, and THEN settle down to solve it calmly?

M. Report said at March 8, 2011 1:01 PM:

It could be a (genetic) Viking thing: Berserkers had both physical
and mental differences from 'normal' people, and could work themselves up
into a rage before battle.

Don said at March 8, 2011 1:47 PM:

keeping in mind--

almost everything we know is wrong.

Gregg said at March 8, 2011 2:30 PM:

When I entered Ranger School I did not adapt to stress well initially and an RI told me if I didn't get control of myself I would wash out. By Florida phase I wasn't rattled by anything and found I could remain calm under duress. It has stayed with me. This is merely an anecdote, of course, but I think it can be learned.

Lono said at March 8, 2011 2:31 PM:


That's my best guess too - I haven't really grilled my Danish relatives about it - due to an old family dispute that is no longer relevant - perhaps I should investigate this further.

In the meantime I am quite cautious about getting into fights - even though I do have some formal martial arts training and should be able to restrain myself - in theory.

(have you ever heard of anything like this before? - I yet to meet someone who knows what I am talking about here in the states - not that I've pursued it much)


You know - that is an interesting question - could large doses of Ritalin make me less resistant to interrogation? I don't think anyone is really resistant to prolonged interrogation anyways - which is why I have always thought I would keep a small explosive device on me - if I ever was engaged in an operation in which I had the real danger of capture from anti-freedom forces. I suppose it could be effective in reducing the time needed for someone to talk - but maybe only in unique individuals as myself - (or those with the excess peptide).

I would not be willing to be a guinea pig for this hypothesis though without serious compensation - probably $20,000 USD would be acceptable - depending on the interrogation method to be used.

Just fyi. ;-)

Lono said at March 8, 2011 2:38 PM:


I wonder if you still don't have an above average amount of that particular peptide in your system. Perhaps it is possible for those with some inante resistance to learn to discipline themselves while others with a greater excess have an easier time adapting to the rigours of such a program.

Glad you were able to master your abilities in this area!

(and that you are on our side!)

teapartydoc said at March 8, 2011 4:04 PM:

Any information about these levels in surgeons?

Froggy said at March 8, 2011 5:23 PM:


I have been a Navy SEAL for going on 21 years now and the behavior/personality disorders that you suffer from are not very prevalent in SOF. I think that you are conflating this research with something else entirely. Are there sociopaths in SOF? I've met a few. But OCD/ADD, etc are decidedly not common, and violent video game addiction and general aggressive behavior is most certainly not confined to SOF operators.

I haven't been tested for this, and I'm not sure that performance under stress is necessarily related to genetics or biochemistry at all. We train specifically to be able to conduct complex tasks under duress and we practice very hard so that we can achieve "muscle memory" if there is such a thing. I have been in the Reserves for the past 10 years with the exception of an Iraq tour in 2007, and my muscle memory for handling weapons remain very good even now when I hardly have the opportunity to train. That doesn't seem to have anything to do with biochemistry on an intuitive level, but I am still quick on the draw and punch holes into holes when shooting.

Ascension into a SOF unit is not based on physical attributes, genetics, or anything else except desire. If you want it bad enough and you are willing to make the sacrifices physically and mentally to endure the training, you are going to make it. Just because you are an occasionally coked out video game addict, doesn't mean you have Tiger blood.

Michael L said at March 8, 2011 9:22 PM:


"Ascension into a SOF unit is not based on physical attributes, genetics, or anything else except desire. If you want it bad enough and you are willing to make the sacrifices physically and mentally to endure the training, you are going to make it."

but how do you know that? :-) Maybe that's the official propaganda line you hear from instructors. Maybe everyone sincerely believes it. Maybe it is profoundly for the best that everyone believes it, i.e. maybe a different propaganda message would produce empirically measurable worse results on key parameters. And yet, all these points are orthogonal to the question "but is that true?"

Lono said at March 9, 2011 8:39 AM:


That is interesting. Most of my family on my father's side were military but I chose not too even though I have always been fascinated with all things military and particularly Special Forces.

I believe I made a wise decision not to join specifically because my unique combination of OCD and ADD do not likely make me a good fit for the military - so it is telling that you have not met many people with phenotypes like mine in your long career.

Like I stated - I had generally believed my ADD (and in my case lower than normal dopamine receptors in my brain) was the underlying cause behind my constant thrill-seeking behavior and uncommon calm and clarity under pressure.

This study, however, makes me curious to see if I do in fact have "tiger blood" as well - and I will possibly pursue finding this out if it is just a matter of a simple blood test.

(And - just for the record - I did coke less than a handful of times - and found it rather unappealing since its opiate nature makes one quite cloudy headed - I certainly wouldn't recommend it to anyone.)

Video games - on the other hand - do improve cognitive function, visual acuity, and hand eye coordination - which is likely why many American soldiers do in fact enjoy it as a pastime.

I think you should seriously consider volunteering yourself be tested for this peptide as well just to help further science in this area.

Tyrion said at October 6, 2011 5:10 PM:

Intriguing study. The paper was from 2000 and not from 2004 if I'm not mistaken. One thing that might be taken for granted in this study is stress inoculation, a psychological coping mechanism that the military grasps very well. It's more than just gradually exposing say soldiers to specific stressors relevant to combat. They're taught to view stress itself differently, as "challenges" that can be solved (and that you have solved over and over again) rather than something uncomfortable that you should avoid. That's resilience in a nutshell. You view problems as challenges, you're able to emotionally regulate yourself, your self-efficacy is high and finally you have the competencies and expertise necessary to solve the problem.

Warning, anecdote incoming: I used to shrink at the slightest sign of stress in the past. But for a long while now I've been absolutely fascinated with mental toughness, what allows others to stay cool even when the sky is falling. Slowly but surely I've been doing some self-inoculating of my own. I started out doing things I absolutely dreaded such as speaking in public (via toastmasters), going to social venues alone and introducing myself to strangers (Yeah, it seems small but I was scared to death doing this). Slowly, and more often than not sloppily, I moved on from challenge to challenge (started viewing them as challenges I could handle) and started to take on more physical challenges such as skydiving (fear of heights), cliff diving (Very little swimming prowess).

More recently I actually attended a two week long "Navy Seals" training simulation run by Navy Seals. I did that very same training exercise mentioned in that study where the instructors tie your limbs together and you have to retrieve your diving mask with your teeth. Now, I'm not fooling myself into thinking that was actual BUD/s training. We didn't have a Hell week, we had a Hell day (lol) and it didn't over a year, it lasted a fortnight. But the point is, I can tell you that I would not have been able to do this a year and a half ago. I wouldn't been able to IMAGINE doing this or jumping out of an airplane or off a cliff.

It's definitely not just a matter of exposing someone to stress. It's a matter of teaching them how to best respond to stress in specific situations, and THEN exposing them gradually to increasing levels of stress as their mental toughness and competencies scale to the tasks. The next challenge for me would probably to train for mental clarity and competency under sleep deprivation and physical duress. I think it's time for me to enlist in the military :D

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