Did you know that the emotional and physical responses you have to stress are set in motion by a series of chemical releases and reactions? Find out what is really going on inside your body and why not all stress is bad.

Stress can make the blood-brain barrier (BBB)—the selective anatomical and physiological barrier designed to protect the brain from large molecules—more permeable to substances not intended to reach the brain. Such a breakdown could permit the passage of substances into brain tissue that normally are kept out. For example, diseases such as Alzheimer’s are believed to render the BBB more permeable. Recent studies indicate stress can do so, too.

Research with mice showed that tiny doses of a large molecule (AChE), previously not thought to be capable of penetrating the BBB, breached this barrier when the mice were stressed by being forced to swim (an accepted protocol).

The potential implications of this are mind-boggling. Effective stress-management techniques may take on a new complexion. According to Al Komaroff in Journal Watch (January 15, 1997), it is plausible that the stress of being in a war zone may have allowed some toxic molecules (and small viral agents) to reach the brains of combatants, conceivably contributing to the symptoms of the Gulf War syndrome.

A 2012 Yale University study showed that chronic stress can actually reduce brain volume. In other words, if you are stressed out all the time, your brain just might shrink. Among its many effects, lower brain volume can lead to impaired cognition and hampered emotional function.

Why does this happen? According to the study, stress and/or depression activate a transcription factor known as GATA1, which regulates the genes that control synaptic connections. When fewer synaptic connections form, brain volume is lowered.

The good news is damage doesn't have to be permanent, however. Brain volume can return to normal, according to the author of a 2000 brain volume study of people with post-traumatic stress disorder. When hormone levels in the brain return to normal, brain volume rebounds to normal size.

A 2012 Yale University study showed that chronic stress can actually reduce brain volume. In other words, if you are stressed out all the time, your brain just might shrink. Among its many effects, lower brain volume can lead to impaired cognition and hampered emotional function.

Why does this happen? According to the study, stress and/or depression activate a transcription factor known as GATA1, which regulates the genes that control synaptic connections. When fewer synaptic connections form, brain volume is lowered.

The good news is damage doesn't have to be permanent, however. Brain volume can return to normal, according to the author of a 2000 brain volume study of people with post-traumatic stress disorder. When hormone levels in the brain return to normal, brain volume rebounds to normal size.