Count calories, measure steps or map the route of a daily run. Tell your friends and cheer the successes. There are thousands of apps, a growing number of gadgets and lively social media networks for health and fitness. Here are some of the most popular digital tools:

Apps

Track calories and weight loss with Lose It! and MyFitness Pal, both free. Map My Run, RunKeeper and Nike+ Running log miles and times for free by using your smartphone's GPS. In need of wacky motivation? Zombies, Run! ($3.99) keeps feet moving by turning a run into a creepy chase, narrated via headphones.

Gadgets

The humble pedometer is getting fancy. FitBit clips on your clothes. Nike+ FuelBand and Jawbone UP both wrap around your wrist. All three devices track daily activity and compare results with friends online. Prices range from $59 to $149.

Social media

If peer pressure keeps you going, most apps and fitness gadgets let you share results with friends through Facebook and Twitter. For more fitness-focused discussion, check out DailyMile.com and Fitocracy.com. Both networks are free and sync with a variety of health and fitness apps.

Katie Humphrey