If you want to stay more upbeat this time of year, doctors and mental health experts recommend you stay active, manage your time well, and not put too much pressure on yourself.

With less and less daylight in December, many of us want to stay indoors more and more. Dr. Curtis McKoy, a cardiologist at Parkridge Medical Center, says we shouldn't get lazy when the weather gets cold.

"The blood vessels will narrow just by virtue of cold weather. That, in itself, can result in elevation of blood pressure," explains McKoy.

Staying in more often can also lead to eating too many calories and too much sodium. Besides watching your diet, Dr. McKoy says it's important to keep your blood flowing. So don't let chilly temperatures keep you away from the gym.

"The most important thing is don't lose your exercise regime, particularly cardio exercise," adds McKoy.

The elderly, smokers, and people with pre-existing conditions such as hypertension or a heart condition should be especially careful. They should monitor their blood pressure at home and compare to their doctors measurements.

Many people also want to be alone this time of year to avoid the social pressures of the holidays. Farlie Chastain, a licensed clinical social worker at Parkridge Valley, says this mood change is common.

"Heading into the colder weather, you're heading toward the holiday season, and along with that comes a lot of expectations, a lot of stress that we put on ourselves," says Chastain.

He says setting realistic goals can help.

"Don't go into the holiday season expecting that you're going to find the perfect gift or do the perfect thing to make everyone around you happy," explains Chastain.

Don't spread yourself too thin. Politely decline some party invitations and set a budget for buying gifts. Chastain says managing your time and money relieves stress which, if unchecked, can lead to depression  and Seasonal Affective Disorder (SAD).

Also, find new traditions for the holidays. If this includes going to a place of worship, find one that works best for you.

"Find a celebration that is simple, that doesn't have huge expectations of time or finances," adds Chastain.

Read More | New blood pressure guidelines

Read More | A few more tips on beating the "holiday blues"