Adults with PTSD have an increased ‘fight or flight’ response

Young adults with post-traumatic stress disorder (PTSD) have an increased ‘fight or flight’ response during mental stress, according to new findings published this week in the Journal of Physiology.

The team at Emory University School of Medicine, led by Dr Jeanie Park, believe that this contributes to the increased risk of high blood pressure and heart disease in PTSD patients.

PTSD is prevalent in populations exposed to domestic violence and any form of child abuse. The lifetime prevalence of PTSD in US adults is 7.8%. PTSD patients are known to have a higher risk for developing high blood pressure and cardiovascular disease.

The researchers also found that adults with PTSD had higher adrenaline levels and less control of their heart rate in response to blood pressure changes. While previous studies have suggested that the sympathetic nervous system- the ‘fight or flight’ response- of these adults is overactive, this study was the first to measure this increased activity directly and provide a potential mechanism behind this response.

They studied the physiology of adults with PTSD, 14 of whom had PTSD and 14 who did not. They measured blood pressure, performed an electrocardiogram (EKG), and recorded sympathetic nerve activity directly in real-time using electrodes placed inside a large nerve. This technique is called microneurography and is considered the gold-standard method for assessing sympathetic nervous system activity in humans.

Commenting on the study, Dr Park said: ‘To protect patients against high blood pressure and heart disease, we need to first understand how their physiology malfunctions. We can then identify potential treatments.’

‘This study looked specifically at adults with abuse related PTSD, so the findings do not necessarily to patients with non-abuse-related PTSD,’ she added.

This is a fascinating study for those with Complex PTSD and PTSD and associated comorbid disorders. It is long known that those suffering from PTSD are hyper vigilant. In hypervigerclance the body’s ‘fight or flight’ response is heightened and this state would be experienced frequently by PTSD suffers frequently during flashbacks and re-experiencing. So what is ‘fight or flight’ and why is so significant ?

It is the body’s response to perceived threat or danger. During this reaction, certain hormones like adrenalin and cortisol are released, speeding the heart rate, slowing digestion, shunting blood flow to major muscle groups, and changing various other autonomic nervous functions, giving the body a burst of energy and strength. Originally named for its ability to enable us to physically fight or run away when faced with danger, it’s now activated in situations where neither response is appropriate, like in traffic or during a stressful day at work or in the case of a PTSD sufferer a flashback. When the perceived threat is gone, systems are designed to return to normal function via the relaxation response, but in our times of chronic stress, this often doesn’t happen enough, causing damage to the body.

The fight-or-flight response, also known as the acute stress response, refers to a psychological reaction that occurs in the presence of something that is terrifying, either mentally or physically. The fight-or-flight response was first described in the 1920s by American physiologist Walter Cannon. Cannon realised that a chain of rapidly occurring reactions inside the body help mobilise the body’s resources to deal with threatening circumstances.

In response to acute stress, the body’s sympathetic nervous system is activated due to the sudden release of hormones. The sympathetic nervous systems stimulates the adrenal glands triggering the release of catecholamines, which include adrenaline and noradrenaline. This results in an increase in heart rate, blood pressure and breathing rate. After the threat is gone, it takes between 20 to 60 minutes for the body to return to its pre-arousal levels.

The fight-or-flight response is also known as the acute stress response. Essentially, the response prepares the body to either fight or flee the threat. It is also important to note that the response can be triggered due to both real and imaginary threats. This real or imaginary threat is what is so important for PTSD as flashbacks or re-experiencing can happen several times a day so a person can stay in ‘fight or flight’ mode for hours.

Based on the study it is possible the impact on an adult with PTSD is significant raised blood pressure. It is  a small study so obviously more extensive studies need to be done but it is yet another indication of the detrimental effect of PTSD on the overall health of a person with the debilitating Disorder and more research needs to be carried out into not just the mental impact on a person’s life but the physiological as well.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s