What Happens to The Brain Under Stress?

Computer-generated images show very clearly that under threat, anxiety and stress there is decreased blood flow and electrical activity in the cortex (the thinking brain). During stressful episodes oxygenated blood and nutrients flow downwards to the area of the brainstem. Neuroscientists often refer to this phenomenon as ‘downshifting’. This fact has serious implications for the work environment – especially in respect to productivity. During chronic stress (downshifting) the brain’s higher centres (cortex where thinking and planning takes place) are less capable of receiving and interpreting information, solving problems and acting creatively. The brain is likely to minimise under the following conditions:

• Potential physical harm
• Intellectual threats – your ideas being attacked, your potential ignored
• Lack of information to meet task requirements
• Emotional threats (feelings of self-esteem under criticism)
• Potentially embarrassing moments
• Cultural social threats (disrespect)
• Isolated from peers, working by oneself
• Unable to pursue personal values
• Lack of access to relevant work resources
• Over-employment – not qualified to do the job
• Inter-personal conflict

A HEALTHY BRAIN DOESN’T NEED TOO MUCH STRESS , Health report from CNN.com, December 26, 2000.

Stress is a normal part of taking a test or dealing with traffic on your way to work. But too much stress can have detrimental effects on your health and wreak havoc with normal brain function.

The problem starts with a perceived or actual threat, which then signals the body to release chemicals into the blood stream to prepare for a survival instinct called ‘fight or flight’.

In the brain, these chemicals take the form of stress hormones, which studies have shown can shrink the area of the brain called the hippocampus. Chronic stress can also harm concentration and reduce a person’s learning ability.

Stress hormones can make you think faster and do better. But if you release too much (stress hormones) you can’t think at all. Learning to turn stress off is the key to maintaining healthy brain function and can protect a person’s quality of life.

When your brain perceives ‘alarm’ or ‘danger’, the body reacts instantly. In these types of intense, stressful or threatening situations, the hormone adrenaline is released from the adrenal glands. They are right above the kidneys and are injected into the blood stream immediately. That immediately speeds up the heart rate, depresses the immunes system, gets your body ready for fight or flight.

No matter how fortunate your life circumstances, no one is exempt from stress. And severe and unremitting stress can be devastating to physical and mental health. Included in the harm resulting from sustained stress are high blood pressure, metabolic disorders such as diabetes, indigestion, impotency and an increased incidence of infections such as flu and colds.

But the most worrying effect of prolonged and inappropriate stress is the harm inflicted on the brain. Cortisol (released by the adrenal glands during stress) damages the hippocampus and thus interferes with the initial coding of new information necessary for learning and memory. They also exert damaging effects on neurons elsewhere in the brain and thereby increase the person’s susceptibility to strokes, seizures and infections.

Some neuroscientists even speculate that the increased incidence of Alzheimer disease may result from the effects of prolonged stress on the brain. Certainly, the target is the same: Hippocampal damage occurs in both long stress and in the earliest stages of Alzheimer’s disease.