(Reuters) - It's the season when yoga classes are cancelled and gyms go on holiday schedules, so to avoid the fitness consequences of all those Christmas parties, experts suggest making a workout plan and sticking to it.

I tell my clients to make sure they have a routine in their back pocket, said Colorado-based fitness instructor Stacey Lei Krauss, something equipment-free that can be done in a small space, especially if you don't have easy access to a gym over the holidays.

Krauss, who created a fitness DVD called Willpower and Grace, said those are qualities we're apt to abandon to family and friends during the holiday season.

It's expected. It's family time; but giving back to yourself is just as important, she said. Will power leads to self-confidence. Will power is self-control: the ability to manage yourself, regardless of what's happening around you.

So when Krauss goes home for the holidays, she'll stick to her morning run and skip the big family breakfast.

My mother will say, 'Oh, do you need to work out now?' I'll say, 'Yes,' she explained. We need to stay on track with what works for us.

Connecticut-based exercise instructor Ellen Barrett's yoga-based classes stress the mind-body connection.

During the holidays mental fatigue can weigh you down as surely as that extra cup of egg nog, she believes, but strengthening the spirit may be as simple as downing a glass of water.

Drink a lot of water. It carries oxygen that will keep you alert, so emotional fatigue won't set in as quickly, she said.

And get moving in the morning.

Do something. Take a 20 minute walk, even if its pitch black outside, she advised.

Even if the exigencies of family and season annihilate the best workout intentions, Barrett said it is still possible to pursue a healthy lifestyle.

Don't think exercise is the only way to stay well, she said. Do a salt scrub, or hit the juice bar for a couple of shots of wheat grass. You'll feel good and you'll have gotten your veggies.

To counterbalance seasonal excess, Jessica Matthews, spokesperson for the American Council on Exercise ACE.L, advocates moderation.

Shift your mindset from that all-or-nothing mentality, said Matthews, an exercise physiologist based in San Diego, California.

We actually measured muscle activity to find the most effective exercises, she said.

The lunges, squats, crunches and extensions target those problem areas of the butt (glutes), the core (abdominals), and the upper arms (triceps).

At 84 years old, fitness instructor Ann Smith, creator of the DVD Stretching for Seniors, said she mainly advises her holiday-stressed clients to relax and have a good time.

Trust yourself. Trust your instincts, said Smith, whose training and love of dance she learned from her mother, an interpretive artist of the Isadora Duncan period.

All you need is to eat, sleep and move every day, Smith said. Walk. Scrub the floor. And if you can't think of anything to do, then start singing. Singing is good exercise.

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