When the thermometer drops, so do most people's inclination toward exercise.

Statistics from the Centers for Disease Control and Prevention show a third of people stop exercising in winter months, said Melanie Carvell, director of the Women's Health Center in Bismarck.

"When spring comes around, it's harder to get back on the wagon," Carvell said.

A few changes can make it possible to continue, or start, an exercise routine when the cold weather hits. For people who exercise outdoors, it means dressing appropriately. For people new to exercising, it means starting small, then increasing duration.

Carvell has a few routes she runs year-round. She changes her workout wear and shoes when the weather becomes colder and there's snow.

The biggest mistake she sees people make when they try to exercise outdoors is wearing the wrong kind of clothing. They end up sweating too much and getting chilled, and they wear too many layers, making a person feel too warm as their body temperature rises.

"If you overheat, you sweat too much," Carvell said.

Usually two layers will suffice: a moisture wicking fabric against the skin covered by another breathable fabric, such as a fleece vest or jacket. She adds a third layer to protect against the wind. On the feet are a pair of shoes with good traction, such as trail shoes.

Outdoor enthusiasts also should guard against frostbite with ear coverings, mittens and a face covering.

"A good mouth covering is good because breathing cold air is hard on the lungs," said Kim Hanson, a certified exercise physiologist at the Human Performance Center in Bismarck.

For people who don't want to exercise outdoors, there are indoor options that can keep a person in shape. It can be as simple as an exercise DVD or include some free weights and an exercise ball, Hanson said. Gyms provide another option for people who want to use a variety of equipment.

Hanson also recommends stretching three to five days a week. For people starting an exercise plan, Hanson recommends starting out 10 minutes a week and increasing by five minutes each week.

(Reach reporter Sara Kincaid at 250-8251 or sara.kincaid@;bismarcktribune.com.)