Social media -- with all the positives it provides for community, exchange of info and plain ol' fun -- can turn into an instrument of profound harm, fueling poor self-image and depression, and encouraging potentially lethal activities such as the recent "Chroming Challenge" that has killed kids who are huffing toxic fumes. Well, it turns out that nifty little track-it-all-and-tell-me-everything device you have on your wrist can turn on you, too.

A study in the Journal of Consumer Affairs looked at how you're engaging with "preventive health technologies" and discovered that the devices are often a double-edged sword. While they can provide accountability, motivation, and encouragement, they can also lead to stress, anxiety and feelings of failure from compulsive over-use. That can derail your efforts to become healthier and happier.

So, what's the formula for the smart use of such monitoring tech?

-- Determine what you want to use it for and why. Tracking minutes of exercise or steps a day? Monitoring your blood pressure? Seeing how much sleep you're really getting and what hours? Choose one to three areas that are most important.

-- Then, set targets that are best for your health instead of sticking with preset goals programmed into the device.

-- Also, recognize that you're on a lifelong journey. Any travel has peaks and valleys -- it's not up, up, up. So, cut yourself a break on days you miss a mark. Start fresh the next day.

For more help setting realistic goals "The Great Age Reboot" and "Ways to Make Exercise More Enjoyable" at iHerb.com/blog.

Dr. Mike Roizen is the founder of www.longevityplaybook.com, and Dr. Mehmet Oz is global advisor to www.iHerb.com, the world's leading online health store. Roizen and Oz are chief wellness officer emeritus at Cleveland Clinic and professor emeritus at Columbia University, respectively. Together they have written 11 New York Times bestsellers (four No. 1's).