BEWARE-Fight or Flight May Be in Our Bones

Halloween ghosts and goblins may be our early warning that THE holiday season is here, raising our stress levels in preparation for gift shopping, cooking, cleaning, relatives, financial pressure . . .

The flight or fight response, our body’s way to prepare us to combat danger and keep us alive:

  • You breathe faster
  • Your heart rate increases
  • Your blood pressure increases
  • Your pupils dilate
  • The blood supply to your skin decreases
  • Your immune system shuts down

Just in time for Halloween . . .  scientists have identified a new hormone that is part of the stress response. It’s a protein called osteocalcin secreted by bone and is involved in triggering the body’s reaction to stress

“Gerard Karsenty, a physician and geneticist at the Columbia University Irving Medical Center, set out to investigate calcification a hardening of bone. In his study of this he eliminated osteocalcin from mice. While that did not change calcification as he had thought, the affected mice did not breed well and had excess fat.”

“Osteocalcin was in the blood of the mice, so Karsenty decided to see if it was a hormone. It was, and was involved in metabolism, fertility and muscle function, and maybe in brain development and thinking. He and others working on osteocalcin wondered why bone would produce a hormone. They thought perhaps bones evolved to help animals escape danger . . . . If so, bones may be part of the fight or flight response.”


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Researchers . . .”found that mice without osteocalcin had a much lower fight or fight response, including less of an increase in heart rate, less increase in blood glucose, and less of a rise in temperature-all part of the physiological fight or flight response. This confirmed that osteocalcin played a role in the response.

“As they continued to learn about osterocalcins role, they thought  that what it was doing was activating the sympathetic part of the autonomic nervous system This part of the  autonomic nervous system is what triggers the fight or flight response. But injecting the hormone into the blood stream did not activate the sympathetic nerve, which was a surprise.”

“What was happening was the parasympathetic part of the autonomic nervous system, which triggers the “opposite” rest and digest response (which come into play when there is no threat), was affected-and it was suppressed.”  

So what osteocalcin does is turns off the parasympathetic autonomic nervous system (ANS) –and allowing the sympathetic ANS to take over and start the flight or fight response.”


“The notion that the parasympathetic nervous system is mediating the effects of osteocalcin on stress is a very interesting finding,” says James Herman, a neuroscientist at the University of Cincinnati, “I think what that means is that the way we currently understand stress is too simplistic.” He says that other chemical messengers may also play a role.”

“Karsenty’s team has also learned that stimulating part of the amygdala increases osteocalcin in the blood.”

Not all scientists are convinced of this work, and it will need to be replicated by others to be sure.  Maybe we’ll know more by next Halloween.

Stress – How to activate your own Placebo

We often don’t realize there are many placebo effects depending on what we think a treatment is going to do for us.  Examples:

  • Fake painkillers cause the release of natural painkillers in the brain called endorphins and work through the same biochemical pathway that an opiod painkiller would work through.
  • A Parkinson’s patient takes a placebo that they think is their Parkinson’s drug, they get a flood of dopamine in the brain, which is exactly what you would see with the real drug.
  • Altitude sickness – someone at altitude takes fake oxygen, there’s a reduction in prostaglandins which actually work to dilate blood vessels that cause many of the symptoms of altitude sickness.

Placebo is NOT imaginary but creates biological changes in the brain that actually ease our symptoms and are very similar to the biological changes when we take drugs.

Some explanations for the placebo effect 

Stress and anxiety — if we feel that we are in danger or under threat, the brain raises its sensitivity to symptoms like pain. Whereas, if we feel safe and cared for and things are going to get better soon, we relax and are not so alert to symptoms.

Physiological mechanisms like conditioning*.   We can all be conditioned to have physiological responses to a stimulus, even immune responses. For example, take a pill that suppresses your immune system and on another occasion take a similar looking placebo pill, with no active drug, your body will mimic same immune response. Astonishingly, it doesn’t even matter if you know it’s a placebo.

Stress can rewire the brain — and create more stress

Like a muscle, the more you exercise any part the stronger it gets.

Brains are shaped by our thoughts and behaviors. Research shows your brain structure, neurochemical and electrical activity responds to and reflects how you think throughout your life.   For example: If you play a musical instrument, speak a second language, train for athletics for eight hours a day – the parts of your brain responsible for performing those activities gets more active and larger. 

If you’re thinking stressful thoughts for the whole day parts of the brain involved in the stress response get larger and other parts of the brain actually deteriorate.  Consequently, the very brain circuits we need to counter stress no longer work as well as they should.  

It’s not as simple as saying, “I’m going to change how I think now. I’m not feeling stressed.”  It takes a long time to change your brain. 

In the middle of your face – your personal placebo “pill” 

When stressed, the brain influences your body AND the body influences your brain.  The stress response speeds up your breathing to pump more oxygen when your brain perceives danger, either real or imaginary.  If you deliberately speed up your breathing when not stressed you’ll start to feel more aroused and on edge.  The opposite is true: Slow your breathing down, forcing your body into a more relaxed state.  Your brain responds with more calming thoughts and feelings.

Condition your own calming response using your breath . . . salivating optional.

* Ivan Pavlov, a physiologist, conditioned dogs so that whenever he gave them food he made a noise, like ring a bell.  Eventually the dogs associated the bell with their food and they would salivate just to the sound of the bell.

A Journey into the Science of Mind Over Body by Jo Marchant, PhD. in genetics and medical microbiology