Read the full article at NBC News.

We're all feeling much more stressed out these days, showing up as increases over the last few decades in how many of us suffer from stress-related diseases and disorders. Even if we're not sick yet, we carry more of the physical markers of stress that lead to future illnesses. We have a full-blown stress epidemic on our hands.

To figure out what to do, we need to understand how it works. The basic story is fairly simple. When we are facing a challenge or threat, our stress system releases cortisol, the "fight or flight" stress hormone. This provides a boost of energy and focus to deal with the stressor. So far, so good: we need a well functioning stress response to navigate our everyday lives.

The problems come when we have excess cortisol in our body over an extended time. Why is this happening so much more often now? One reason is that there are more stressors, experienced more frequently. A second, hidden reason is biological. As stress increases overall, more of us will develop a poorly regulated stress system as a result of stressful experiences in early life, while we are still in the womb or in the first year of life. If we become "stress dysregulated" (SDR), we react more often, more strongly and for a longer time.

Stressful social experiences "get under the skin" through an "epigenetic modification" that changes how our genes work, leaving the DNA in our genes intact. This makes it difficult or impossible for the stress response to shut down, because a key gene in the feedback loop has been "methylated." This leads to excess cortisol, which has in turn been clearly linked to many diseases and disorders, as well as early mortality. A harsh early life environment sends a signal that "amping up" the stress system is the best defense against danger — in other words, it is a chance for the genes to "listen to the environment" in terms of what that young life is likely to encounter.