Delmetria Millener of Dallas, Texas, endured years of an emotionally and physically abusive marriage before it ended in divorce. "He called me ugly and fat when I was a size 7," Millener says. "I cooked and cleaned incessantly, but he accused me of not being as good as his girlfriend. Then, after three kids, he said that if I ever left, no man would want a woman with three kids."

When she did find the courage to go out on her own, Millener's former husband, she says, didn't pay child support or visit the children. But rather than harbor anger – and yes, she was angry – Millener went about the difficult work of healing herself. And to do that, Millener knew she needed to find forgiveness.

"I had to accept that I'd gone through this and that I'd learned strength and perseverance because of it," she says. "I was not going to let resentment for him steal joy away from me."

When Millener ran into her ex-husband several years later, she was a different person. "At first, I was ecstatic because I knew how unhappy he was," she says. "Joy then turned to pity and I felt sorry for him. Now, I feel nothing. It's almost as if I never knew him. I am at peace with myself, knowing that I will not hold hatred in my heart."

Why Harboring Can Hurt You
Holding a grudge can have deleterious effects, both mentally and physically. It's stressful to internalize anger and the desire for revenge, especially in situations complicated by a loss of control. Legal issues can take years to resolve, and the betrayal of a friend can take a lifetime to mend.

The chronic stress of harboring ill feelings begins an age-old physical response that releases the steroid, cortizol, into the body, says Dr. Peter Degnan, a board certified physician in Portsmouth, N.H., who specializes in stress reduction. While this stress-related hormone can give the body the life-preserving boost it needs in emergency situations, we're no longer running from dinosaurs.

Excess levels of cortizol increase fat storage and lower the immune system. Studies also have shown that stress causes muscle atrophy, dulls emotions and lowers intellect. Why? People under severe and prolonged stress release a steroid compound known as corticosterone, and this causes the dendrites (parts of nerve cells in the brain) to shrink and die. In short, being mad can make you dumb. It can also make you forgetful, as the same process inhibits learning and memory.

What's the best course of defense? Forgiveness. "Your relationship with yourself is the most important relationship," Dr. Degnan says. "You have to forgive. This may mean making amends with someone, but when that person is unable or unwilling, even internal forgiveness is OK. The most important change happens from within."

Journey to Forgiveness
Forgiving seems like a simple act, but it can be a long and difficult process. Usually, one of two things jumpstarts the forgiveness process, says Dr. Degnan. "Something occurs, large or small, that causes a person to suddenly come to the decision that they don't want to harbor ill feelings, or a counselor or spiritual mentor helps a person reach this decision," he says.

Once the decision is made, the real work begins. Forgiveness is a process, one that requires inward change. It's not just about telling someone "I forgive you." Genuine forgiveness requires you to know yourself and to let go of anger that has been burnished until it gleams.

How can the journey begin? There are many paths to forgiveness. Try them all; find one that works for you. Journaling or writing can help you express internal anger or fear and provides a cathartic release. The added benefit is that writing down your innermost uncensored feelings provides you with objectivity. What you've really written may surprise you.

Try meditation, yoga or tai chi. While your meditative task is to clear your mind, not to go through a mental checklist of grudge-holding, unwinding may help you to later look at the situation objectively. Go for a walk in the woods, paddle down a river, run through the park – the exercise will help combat the effects of bad stress and give you a sounding board for your own mental turmoil.

Once you've reached forgiveness, don't stop the good behaviors you have started, says Dr. Degnan. If you started walking each day to think about forgiveness, keep it up. Don't risk a return to old emotional and physical habits. "Contemplative exercise is a wonderful practice to continue anyway," Dr. Degnan says. "There are so many stressors the body accumulates; having exercise as a regular part of your life will significantly reduce long-term complications."