There is no escaping the fact that what happens on the inside of our bodies can affect the outside, like stress for example. It is a complex business that leads to a major study recently.

We all know what stress feels like heart pounding in the chest, breath coming faster, muscles tensing, a burst of energy and every sense on red alert.

In very small doses, stress can actually be a good thing. But when life's demands exceed your ability to cope, stress becomes a threat to both your physical and emotional well-being.

Few people realize stress from within can also lead to external visible skin damage.

"We have had anecdotal evidence for a long time that psychological stress can affect your skin," says Tom Mammone, executive director of Clinique Research and Development.

"This topic is one that has long been of interest to us so when the opportunity for Clinique scientists to do targeted research on the subject came about, we took it."

The findings from their study confirmed that emotional or psychological stress can damage the skin's natural defenses. "In addition, the research led us to have a clearer understanding of how psychological stress can damage the skin. Armed with this knowledge, we were able to look into ways to combat this visible damage topically," says Mammone.

When the body is under stress, it releases hormones including adrenaline and cortisol. These stress hormones can cause irritation and loss of immune function in the skin and the effects are similar to what happens during the natural aging process.

Mammone says that when skin is irritated it can lead to a compromised barrier function. A strong barrier keeps moisture in and external aggressors and irritants out. When the barrier is damaged, moisture evaporates more rapidly and irritants can get in more easily, both of which cause damage to the skin.

In addition, when the skin's immune function is compromised, its ability to fight off external invaders and suppress damaged cells before they multiply is also compromised.

And that matches the traditional Chinese medicine belief that ongoing day-to-day stress affects the liver. In TCM, the function of the liver is to regulate and guarantee the flow of qi, the vital substance of life energy in the body.