It's supposed to be the happiest time of the year, but don't tell that to the patients who mob the offices of San Diego cardiologist Dr. Mimi Guarneri between Thanksgiving and New Year's.

Some complain of what doctors call "holiday heart" -- skipped beats, high blood pressure and angina due to stress or overindulgence. Others feel physically and emotionally overwhelmed, distracted by thoughts of difficult relatives or missing loved ones.

Guarneri, medical director of the Scripps Center for Integrative Medicine, has different advice for her patients, depending on their situations. But she's always sure to emphasize one theme: relaxation.

"The one thing is do is to take time out, take a deep breath, connect your mind with your body by simple breathing," she said. "And remember to not sweat the small stuff."

Easier said than done, of course. But when it comes to crippling holiday stress, specialists say the simplest pieces of advice are also the best.

Dr. Redford Williams, director of the Behavioral Medicine Research Center at Duke University in Durham, N.C., advises people to be reasonable with their expectations from the season, and to anticipate trouble -- ranging from long lines at stores and airports, to bouts of sadness when images of absent loved ones come to mind.

By readying yourself for these moments, "they won't come as a shock when you realize, 'I'm getting ready to honk my horn or get steamed over this person who just pulled in front of me.' If you can do that, you can probably head off some of it," Williams explained.

He said it's not clear how many people get the blues around the holidays, but it's probably not uncommon. "It's perfectly normal to get a little bit depressed or a little sad during the holidays at one point or another," Williams said.

However, it may not be as bad as some might assume. In recent years, American researchers have looked at local statistics and debunked the long-held assumption that suicide rates shoot up around the holidays.

Not every episode of Christmastime depression is minor, however. If you find yourself early in the new year having trouble with sleeping or eating -- doing either one too much or too little -- it's possible that you've fallen into a clinical depression.

If that might be the case, "You should seek some professional evaluation and possibly treatment," Williams said.

In other cases, a little self-help can be key. "In the grand scheme of life, we say, 'Don't sweat the small stuff,'" Guarneri said. "We have to realize that a lot of stress is what we put on ourselves, not what other people are putting on us."

If you're alone and feeling isolated, she said, "get out and do service work, which brings joy to people." And, if you have the opposite problem -- too much to do and too many people to worry about pleasing -- learn to do less. "None of this is worth dying for," she said.