At this age, it is key to rack up 30 to 40 minutes of exercise most days and develop a regular stress-reducing practice such as meditation or yoga. To build bone, resistance training and weight-bearing exercise (running and jumping, not biking and swimming) are key. Lastly, chill out with mind-body practices. Here are our best ideas to stay fit and fabulous.

Even if you haven't tried one since gym class, the multitasking push-up deserves a prime spot in your fitness routine.

Even if you haven't tried one since gym class, the multitasking push-up deserves a prime spot in your fitness routine.

These morning and evening yoga routines will keep your energy up and your stress levels down -- and each takes just 15 minutes

This interval routine, which takes about 30 minutes, alternates between spurts of lung-strengthening cardio and focus-enhancing breaths.

This quick routine can help you hit the reset button on body, mind, and spirit.

Use the following workout, a combination of complementary core strengtheners and stretches, to tone your belly -- and build a stronger, more centered you.

This fusion of weight training and yoga builds strength, increases flexibility, enhances focus, improves core stability, and calms and centers

Close your office door or find a quiet space and follow these easy steps -- and that cafe run might soon be a thing of the past.

Try this intense, three-step comprehensive routine that maximizes results in just over 30 minutes. By fusing Chinese exercise, Pilates, and weight training, it tones the body as it trains the mind in the power of positive thinking. By practicing this series three times a week, on alternating days, you'll boost your confidence and body image.

This Pilates-inspired routine improves posture, focuses the mind, creates alignment, opens up the body, and releases tension.