The rapidly evolving technology of mobile computing has brought us smart phones and tablet computers. With the hectic lifestyles we live, here are some free health apps you may find useful.

Having a stressful day? The Vibrating Masssager turns your phone into a real vibrating massager. Features include a basic massage, lifelike sound, the ability to change vibration intensity, and graphics and animation that synchronize to the vibration.

Heart Rate by LogYourRun lets you keep track of your heart rate.

Features include:

Heart Rate/Pulse Measure — Measure your heart rate by tapping your pulse or counting your heart beats.
Heart Rate Zone Calculator — Enter your maximum and resting heart rate and the app calculates your heart rate zones. If you measure your heart rate, it will show you which zone you are in.
60beat Heart Rate Strap — The app can read your heart rate from an analog heart-rate strap if you plug a 60beat device into your iPhone or iPad (sold separately).