1. Your brain's in pain.
When you're stressed, your hormones set off a series of neurochemical events in your brain that stimulates your nerves and causes your blood vessels to swell. The result: tension headaches and migraines. There are ways to cope, however. Studies have shown that people who practice relaxation and stress-management techniques cut the number of headaches they have by as much as 35 to 50 percent.
2. Your stomach churns and burns.
You've been waiting in the check-out line at the grocery store for 20 minutes, you're late for preschool pickup, and you've spilled coffee all over your new pants. By the time you get back in the car, your stomach is a queasy mess. Those little daily hassles can actually disrupt gut function and cause digestive problems just as much as major life changes can. "Anxiety and stress can cause the body to produce more digestive acid, which leads to heartburn. They can also slow the emptying of food from the stomach, which causes gas and bloating, and may even increase the number of times your colon contracts, leading to cramping and diarrhea," explains Deborah Rhodes, M.D., a consultant in internal medicine at Mayo Medical School, in Rochester, Minnesota.
3. You sneeze up a storm.
Does it seem as if you come down with a cold every time you have to give a presentation at a PTA meeting? It isn't just your imagination: Stress suppresses the immune system, making it easier for you to get sick. In a study at Carnegie Mellon University, in Pittsburgh, researchers surveyed volunteers about what was going on in their lives, and then infected them with a cold virus. The men and women coping with stresses ranging from a bad marriage to unemployment were twice as likely to get sick as those with fewer problems.
4. You're up all night.
The day is done, but your mind's still buzzing -- leaving you to toss and turn in bed. You aren't the only one lying there wide awake. "Stress is the number-one cause of sleep deprivation and insomnia," says James Maas, Ph.D., author of Power Sleep. "That lack of shut-eye, in turn, makes you irritable and anxious, decreases your ability to fight infection, and impairs your ability to concentrate." Sleep problems also create a vicious circle: Once you're sleep deprived, your threshold for dealing with everyday problems is even lower -- keeping you stressed out and making it more difficult to sleep the following night.
5. You pack on the pounds.
"When your body perceives stress, it assumes you need physical energy to protect yourself and releases adrenaline and cortisol," explains Pamela Peeke, M.D., an assistant professor of medicine at the University of Maryland School of Medicine, in Baltimore. "These hormones trigger the sensation of being hungry -- which women, especially, respond to by eating fats and carbs." (Now you know why you head for the vending machine every time your boss gives you another impossible deadline.)
6. Your back attacks.
While the physical rigors of being a parent -- lugging baby gear, racing after small children -- can contribute to backaches and muscle twinges, research shows that most chronic back pain is caused by psychological stress. "Tension triggers the sympathetic nervous system to reduce blood flow to the muscles, which makes them prone to spasms," says Douglas Johnson, M.D., coauthor of Back Sense. To make matters worse, people tend to hunch over and tense their shoulder and neck muscles when they're anxious -- exacerbating back problems.