If you want to lose weight or just remain healthy, regular exercise is the best way to do this. Some people have a hard time getting motivated to exercise while others simply don't know where to begin.

Thanks to smartphones and tablets, getting motivated or even getting started is no longer a challenge, thanks to the following four apps.

1. Fitness Builder

If you want to learn how to exercise, Fitness Builder can be a big help. This app contains over 5,600 images and videos of proper exercise routines. Everything from stretching to intense workouts are available through the app, and you even have the option of using a personal trainer.

The app also contains workout and performance tools to help you get the most out of your workouts, including fitness tracking, scheduling, calculators and graphing. You can track your body stats and even share workouts with friends and family. You can also create your daily or weekly workout routine, and even share your progress through Twitter or Facebook.

2. Beatburn Treadmill/Outdoor Trainer

If you workout with music, you either create your own playlist full of songs to keep you motivated, or you end up skipping through those slower songs in order to help you keep up your pace. But you no longer need to do this, thanks to Beatburn Treadmill/Outdoor Trainer. Beatburn uses a beat-sync technology that will change the beat of your music in order to correlate with your pace.

The technology used in the app selects the best songs from your library based on your pace. If you slow down, it will change songs in order to provide you with the most accurate music. It also comes with 24 of its own high energy music.

You will also be continually motivated by a real person's voice. Special messages of encouragement will come through your speakers every now and then to ensure that you are constantly motivated to continue working. And when you're all done, you can post your progress to Facebook or Twitter.

3. RunKeeper

If you are exercising and you want a personal trainer, RunKeeper is the best app to have on hand. You can track your runs, walks, hikes and bike rides using the app.

The app will keep track of your stats, including distance, pace and time. You can even get personalized coaching through your headphones while you're working out, and the app even lets you listen to and control your own music to keep you motivated. If you see something interesting while working out, you can even take pictures.

You can also get notified when you achieve a new personal best, and you can set goals and track your progress towards achieving them. You can also track your route and run the same one over and over again. And if you feel like sharing your progress, you can do so through Facebook or Twitter, or even share with other RunKeeper users.

4. Pret-a-Yoga

If your favorite form of exercise is yoga, this is the app for you. Pret-a-Yoga will help you practice yoga in the comfort of your own home. The app features a personal guru who will help guide you through each session and teach you the correct way to do each pose and how to breathe.

The app contains four different stages for different level users, and it is suggested that you start slow and work your way up through the levels for the best possible results.

So if you’re into hardcore workouts or just getting started, use these four apps to help you on your path to being healthy.

Caleb Grant is a writer and fitness expert. He likes to give tips on how to keep fit by exercising and eating healthy foods. Caleb recently wrote about the nutrition in nuts.