Stress much? Whether it stems from big-picture issues like constant work overload or money trouble, or from stressful daily minutia like getting stuck behind a slow truck during our daily commute, we can all commiserate over the nagging anxiousness that stress inflicts.

In fact, according to the American Psychological Association’s 2010 Stress in America survey, the majority of American experience unhealthy stress levels in daily life and more than 40 percent of all adults report lying awake at night due to stress. In addition to that negative feeling, you may vaguely sense that you don’t feel or look your best during a particularly bad week.

But, what you might not realize is that stress is enemy numero uno to beauty. Don’t stress over it though—YouBeauty is here to help you chill out.

First, though: What exactly is stress?You know what it feels like, but what is going on in your body that causes all that unease? On the most basic level, it is an immediate danger that fires up the sympathetic nervous system, which is responsible for the fight-or-flight response you have to a snarling dog or tray of dishes smashing to the floor at a restaurant. During this process, a number of chemicals flood the body, including epinephrine (aka adrenaline) and cortisol (the “stress hormone”), which in turn increase your heart rate and blood sugar levels and prepare you for a confrontation or a sprint.

This basic type, called acute stress, doesn’t negatively impact your health—in fact, dozens of studies indicate that it is a beneficial, immune-boosting response. Chronic stress, however, can be quite harmful. This is the cumulative feeling of frustration from ongoing problems, such as long hours in a cubicle, a lingering illness or tension with your significant other. Here, the sympathetic nervous system is constantly on and the body can’t get a break from the stimulating fight-or-flight chemicals. The result: Excessive wear and tear on the body and mind, as well as consequences for your looks.

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It’s a topic that Dr. Amy Wechsler, YouBeauty Dermatology Advisor, extensively explores in her book, “The Mind-Beauty Connection.” According to Wechsler, stress is “the root of all evils today, at least when it comes to health and beauty.”

Frazzled Hair and Skin:
Americans will spend an estimated $25.6 billion on hair and skincare in 2011, more, by far, than on any other beauty products. But, stress has repercussions for your hair and skin, which you can’t overcome with a dollop of conditioner or smear of cream.

Telogen effluvium, a scalp disorder that stunts hair growth and causes an increase in hair shedding, is triggered by physically or emotionally stressful events including childbirth, chronic illness or surgery. Hair loss often occurs months after the event, making a direct cause difficult to pinpoint. Stress can also worsen hair loss due to alopecia, an autoimmune disorder in which the immune system attacks hair follicles, typically leaving round bald patches on the head or body.

Stress mars the skin to an even greater degree, attacking on multiple fronts. This is no surprise. The skin has the largest surface area of any organ in the human body, it’s chock-full of nerves and blood vessels and it’s directly connected to the brain.

Acne is one of the most common stress-induced skin ailments. While the connection between stress and acne may seem obvious to anyone who has broken out during a hard week, the evidence was mostly anecdotal until around a decade ago.

In 2002, Stanford University research dermatologists first showed a direct correlation between breakouts and stress in adults. A few years later, in one of the largest acne studies to date, researchers from Wake Forest Baptist Medical Center showed an increase in acne during stress—specifically red, inflamed pimples. Correlation does not mean causation, of course, but since then, experiments by Christos Zouboulis, M.D. from Dessau Medical Center in Germany have shown a physiological link between stress-related hormones and acne. “For many years, we thought there was a link between stress and acne, but science didn’t offer the answer,” says Zouboulis. “But now our experiments show that it’s probable.”

READ MORE: Why Stress Management Should Be Part of Your Beauty Routine

Stress, it turns out, is partially to blame for several other common skin problems, from virus outbreaks to wrinkles. Researchers have tied it to eruptions of previously dormant herpes viruses, including the cold-sore-causing Herpes simplex, increased activity of inflammatory skin disorders such as eczema and psoriasis, and prolonged wound healing on both the body and in the mouth (studies from Ohio State University show a 24 percent and 40 percent increase in healing time for wounds on the arms and mouth, respectively). The stress hormone cortisol breaks down collagen, a protein in the skin that helps keep it strong and elastic. Less collagen means more wrinkles. Wechsler points out that stress can age you and make you look three to six years older.

Stress can also indirectly affect the skin. This may happen when you don’t have the time or strength for proper skincare. In some cases, you might excessively pick at blemishes (called acne excoriee, in medical-speak), which are already exacerbated and might take longer than normal to heal. Or, you may shirk basic beauty regimens. “When people are stressed out they don’t take as good of care of themselves,” explains Wechsler. “They might not take the time to cleanse and moisturize, or they may be drinking too much or engaging in other unhealthy behaviors.”

Stress and Your Smile:
Americans will spend around $3 billion on oral hygiene products this year, yet poor choices and unhealthy behavior can lead to its neglect. Stress is a major indicator for gum disease. A 2007 literature review by Brazilian periodontists suggests a correlation between stress and gum disease, which could be due to a decrease in flossing and brushing. Cortisol may also play a role, says Don Clem, President of the American Academy of Periodontology, because the hormone’s elevated levels during stress may exacerbate the inflammatory response to bacteria in the mouth. This inflammation, he says, leads to the worst symptoms of periodontal disease: red, swollen and bleeding gums. Gum disease can also lead to tooth decay or even tooth loss.

Stress is also implicated in sleep bruxism, or teeth grinding, which involves clenching or grinding the teeth during sleep. In 2010, researchers at the National Institute of Aging showed that bruxing was far more common amongst stressed patients, results that agree with a number of other studies. Tooth enamel is a crystalline material that can crack under too much pressure. According to Ohio-based dentist Matthew Messina, these crack lines can fill with stains from food or beverages—coffee and tea for example—making them appear discolored and aged. Grinding on the molars can shorten the vertical height between the tip of the nose and the chin, Messina adds, which can cause the corners of the mouth to turn down. And, the wear and tear on your front teeth flattens their naturally rounded edges, which makes them—and you—appear older.

Get Your Z’s, Eat Your Veggies and Relax:
Stress directly affects the quantity and quality of sleep, which then in turn can increase stress levels during the day, says Eric Powell Ph.D., the Director of Insomnia Center and Research at Clayton Sleep Institute in St. Louis. His research team has found that while the amount of sleep we get each night is important, equally important is sleep consistency—when you go to bed and when you get up—as well as quality. Loss of even a few hours a night can increase the body’s inflammatory response, which raises your risk for a litany of diseases. It can also increase levels of the hunger-stimulating hormone ghrelin, which could lead to overeating and obesity.

RELATED RESEARCH: Lack of Sleep Leads to Snacking

One important goal to combat stress, then, is getting consistent sleep. But, what can you do with all this other information? You can’t avoid stress, but its physical manifestations, whether they include hair loss, breakouts or worn teeth, are warning signs that it’s getting the best of you. And, beyond beauty and mental health, stress is linked to chronic illnesses such as diabetes, heart disease and hypertension, which give an even greater incentive to rein it in.

Some ideas for alleviating the stress in your life include relaxation techniques such as meditation, tai chi or yoga, or behavioral modification therapy, which can teach you new ways to cope with your personal stress triggers.

Other healthy, stress-reducing choices mirror the basic things that physicians recommend for overall wellbeing: “You can take very small, very simple steps every day,” says Dr. Beth Ricanati, YouBeauty Wellness Advisor. “Be mindful of your sleep, choose fruits and vegetables over processed food, and move your body.”