Blanca Famadas has discovered a new way to “stay faithful and true” in her decision to have a healthier life: her smartphone.

The teacher at St. Philip’s Episcopal School in Coral Gables has joined millions of people who are using smartphone apps to monitor everything — from exercise to blood pressure to blood sugar levels to the number of calories consumed.

“I have always walked a lot, from 45 minutes to an hour every day, but until now I never really knew how much,” Famadas says. “A colleague recommended the app Nike + Running. You download it to your cellphone and it keeps track exactly of how much you have walked and how long it has taken you.

“Knowing that motivates me to continue and allows me to know whether I have to speed up my pace or slow down to reach my daily three miles. I love knowing this and the best part is that the app does not interfere with you using your phone to talk or listen to music while you walk.”

Doctors, too, often recommend them for their patients.

“There are more than 100,000 apps related to health issues available through the operating systems of Apple, Android and Microsoft,” says Dr. Joseph Gutman, endocrinologist at Mount Sinai Medical Center in Miami Beach. “Not all are good or cover everything, but I encourage my patients to explore whatever is available because the best patient is an informed patient.”

The apps can be particularly good in tracking diet and exercise.

“I recommend them to people who have smartphones because several studies have demonstrated that keeping a log is crucial for losing weight and staying motivated to exercise,” says Sonia Angel, a nutrition specialist at Memorial Regional Hospital in Hollywood. “Before, we used to ask people to keep a journal and they had to have a pencil and paper all the time, which ended up becoming an excuse for not doing it.’’

A study by Northwestern University published in December 2012 by the Archives of Internal Medicine showed that a year after following 70 people with an average age of 58, those who used apps lost up to 15 pounds more than those who kept a log by hand.

In South Florida, preliminary results of a recent initiative sponsored by Florida Atlantic University’s Exercise Science and Health Promotion demonstrate that “those students who use apps are more enthusiastic and participate actively in the process of logging calories to lose weight,” said Natalie Díaz, one of the researchers of the project, led by Dr. Tina Penhollow.

Here are some apps recommended by users and medical experts:

•  Epocrates : Features a database of all available medications in the United States. The free version allows users to review possible contraindications and generic alternatives, identify pills and check out their interaction with up to 30 medications at the same time. There is also a $159 yearly subscription that provides specialized information about specific diseases, clinical studies and laboratory guidelines.

•  My Fitness Pal: Features a database with calories and nutritional values of more than two million foods and meals, from bananas to elaborate pasta dishes prepared by national restaurant chains. It allows users to log their weight, calculate the calories they must consume daily, and keep a log of food and of exercises performed. It also provides progress reports and allows sharing information with friends.