JACKSONVILLE, Fla. -

We exercise to lose weight and be healthy, but there's more to your 30-minute routine that's helping you live longer.  We have four 'other' benefits.

Exercise can help you sleep better.  A study by the Sleep Disorder Center at Northwestern University found 30 minutes of cardio four times a week can help you catch an extra 75 minutes of sleep every single night.  Exercise raises your body temperature and as it drops back down, it helps to induce sleep.

"You feel looser. The muscles aren't as tight and the endorphin release that you get during exercise. The feel good feeling, it helps you get sleep," says Jason Rice with Definitions in San Marco.

Exercise can also help you stay sharp.  Scientists say just 45 minutes three times a week can help your brain turn back the clock three years.  A study in mice showed a 30-percent growth in neurons.

"I believe the main point of that people overlook is blood flow. Exercise increases blood flow to every part of the body, especially the brain. And a lot of great athletes find they think better in the skill after exercise," explains Rice.

Exercise can help you stay vertical.  30 minutes at the gym can increase your bone mineral density up to three percent and reduce your fracture risk by 50 percent.  The reason is bone must be stressed to grow stronger, that's according to the Journal of Cardiopulmonary Rehabilitation & Prevention.

Finally, exercise can give you that much needed energy boost.  A study out of the University of Georgia found those who did low-intensity biking for 20 minutes, three times a week, felt 65 percent less fatigued just six weeks later.