Stress is a popular topic and this paper reviews a number of novel aspects of the effects of stress—on the brain and on immune function. This is a particularly good and timely review that summarizes data but within a conceptual framework.

  Does it describe a new discovery or new methodology that's useful to others?

It summarizes a conceptual framework for understanding the protective as well as the damaging effects of stress, or what we would prefer to call "allostatic load" for reasons described below.

There is a conceptual aspect and a review of data in the article.

Concept: Acute stress increases immune function and also enhances the formation of memory of potentially dangerous events, whereas disregulation of the stress response systems by overuse or failure to shut them off when no longer needed results in suppression of immune function and remodeling of brain cells in the hippocampus. This is captured in the concepts of allostasis and allostatic load. The concept of "allostasis" (active responding of biological mediators that maintain homeostasis) leads to the concept of "allostatic load" (the wear and tear on the body due to overuse of allostasis by repeated stress or disregulation of the mediators—failure to shut them off when no longer needed).

Data: Besides talking about acute and repeated stress effects on the immune system, the article also describes how neurogenesis in the dentate gyrus and remodeling of dendrites of hippocampal neurons are involved in the response to repeated stress.

Stress is a term that is overused. The new conceptual framework described above provides a way of understanding that the hormones produced during stress are actually essential for adaptation and survival but can cause problems if not properly regulated. People should not be afraid of them! Their overuse or disregulation is what causes problems—e.g., immune suppression, visceral obesity, atrophy of brain structures like the hippocampus, i.e., allostatic load. These changes are cumulative over time and are increasingly evident with aging—so we are talking about one aspect of the rate of aging! Lifestyle (diet, alcohol, smoking, etc) increases allostatic load and moderate exercise reduces it, so it is not just "stress" that causes allostatic load. The concepts are more important than remembering the words, allostasis and allostatic load, which is a mouthful!

In summary, there is an inevitable price for being alive and we can make choices that help us make allostasis more efficient and minimizing allostatic load, although we can never eliminate it! Choices include the things that make sense, like eating sensibly, exercising regularly, getting enough sleep and having a break from work. These are things that our mothers and grandmothers tried to teach us, but they make even more sense when they are based upon an increasing understanding of mechanisms of adaptation and damage.