In this week's PEOPLE magazine, McCain, 54, reveals her painful condition in the hope of raising awareness and encouraging more research. She says one of her first challenges was finding the words to describe how painful the headaches can be. When she first told her husband, a former POW during the Vietnam War, she used a word she knew he would understand.
"Torture," she says. "Being tied to a chair for four days. I can't imagine how unbearable that pain must have been, but yeah, I can, because a migraine may come close."
Downplaying the PainMcCain says that for years she tried to downplay the pain, not wanting to burden her family – and because her husband had suffered so much during the more than five years he was a prisoner in Hanoi. "There were times when I felt a little bit inadequate with my pain problem," she admits. "But I had to get over that because I didn't live in John's shoes and he didn't live in mine. He doesn't always understand [migraines] but he knows they are real."
The year she spent on the campaign trail during her husband's quest for the White House was particularly trying. Bright lights, for instance, can be a trigger for headaches. "Whenever I had those huge dark glasses on, that was always a sign," she says. "Sunglasses are a migraine sufferer's best friend."
McCain lost weight during the non-stop days of public appearances, dropping to below 100 lbs. on her 5'7" frame. "Some people gain weight during times of stress but I lose weight," she says. "I was way too thin." She has since regained some of the weight.
Empty NestLooking back on the trials of the campaign trail today, she seems to feel relief. "It was a good race, but I'm glad it's over," she says. Asked about current First Lady Michelle Obama, McCain says, "She is doing a great job. She's raising her children and being a good wife. Good for her."
Today, McCain says her own focus is on her kids: Meghan, 24, is blogging and writing a book ("She's a bright girl," says Mom, "and I think that's what she's made for"); Jack, 23, is in pilot training in Pensacola, Fla.; Jimmy 21, is a lance corporal in the Marine Corps; and Bridget, 18, is about to start her senior year of high school. "I'm having a little empty nest syndrome," McCain admits.
Next up: raising awareness about migraines. McCain will address the International Headache Congress on Sept. 10 in Philadelphia. "I'm one of the millions who suffer," she says. "It's time for us to shake things up a bit."
For much more from Cindy McCain's interview, pick up the new PEOPLE, on newsstands Friday
For information on dealing with migraines, check out Health.com