OK, so you haven't been eating as much fiber as you should. That's why this is happening, right? Not necessarily. Studies show that low oxygen and carbon dioxide levels caused by quick, shallow breathing deprive your digestive organs of the fuel they need, resulting in constipation. Rhythmic breathing can be a great way to massage your digestive organs to get things, er, moving along.

To contract your digestive muscles, you want to alternate short, explosive exhales with longer inhales. But you've gotta be sure your exhales are powered by deep contractions in the lower belly, not in your chest. Here's how: Sit up straight with your feet planted on the floor. Cup one hand around the other and press gently against your lower stomach to feel where the contraction is coming from. Quickly contract your lower stomach, pushing a burst of air out of your lungs, then quickly release the contractions so your stomach sucks air back into your lungs. Repeat at about one exhale-inhale every one to two seconds and aim for 25 cycles. Combine this breath with a tummy-contracting move for best results: Inhale deeply, flexing your stomach muscles as you inhale. Hold your breath, and contract and expand your stomach rhythmically for as long as you can. Exhale completely. Repeat three to five times.

During times of stress -- like before a big presentation when it's all on the line -- you're more likely to be chest-breathing, a shallow type of breathing that only causes your shoulders, neck and jaw to tense up. What you need to get you through a big day is diaphragmatic breathing. Breathe in deeply through your nose and allow the area below your bellybutton to fill like a balloon. Next, feel your rib cage, expand as the middle portion of the lungs are filled. Finally, fill the upper third of the lungs. Exhale slowly, contracting your belly as you breathe out. Repeat for 5-10 minutes for a relaxed energy and looseness before your big interview.

Tired of counting sheep yet? Focus on making your exhales longer than your inhales to calm the body and reduce tension, which can lull your insomniac self back to sleep. Or, next time you're staring at the cobwebs on your ceiling at 2 a.m., try alternate nostril breathing (aka yoga breathing exercise Nadi Shodhan):

• Sit up in a comfortable position. Take your right hand, palm facing toward you, fingers extended, and bend your pointer and middle finger so they curl into your palm.
• Rest your ring finger near your left nostril and your thumb near your right. Take a big breath in and a big breath out. Then, close off the right nostril with your thumb and inhale through the left nostril fully for a count of four. At the top of that breath, close off the left nostril with your ring finger, hold and retain the breath for a count of four, and then release the right nostril and exhale for a count of four.
• Inhale deeply for a count of four through the right nostril, close it off, hold and retain the breath for a count of four, and then release the left nostril as you exhale completely through it for a count of four. Inhale deeply through the left, and repeating the cycle.

Repeat until you feel more relaxed -- this style of breathing balancing both sides of your brain to calm your nervous system.

If you're on your umpteenth Pilates class and not seeing any results, your breathing may be the problem. The quick, targeted reps in Pilates classes are all for naught if you're not practicing lateral breathing. The next time you're going through the motions, inhale through your nose when the belly is flat and engage your abs by pulling your bellybutton down toward your spine -- imagine your ribcage expanding laterally as your fill your body with air. On your exhale, forcefully (and audibly) push air out of your audibly to keep abs engaged through the entire workout. Feel the burn.

It's all well and good that you excel at child's pose, but downward facing dog is one of the most essential in the majority of yoga classes, and takes a little more effort and flexibility. Next time you feel like toppling over, cut the mouth breathing and focus on your nose, says Terri Walsh, celebrity fitness trainer and creator of the ART Method. "Downward Dog demands an even and steady breath at all times with the mouth closed. The breath is important in helping to calm the mind and focusing on the breath evenly through the nose, clears nasal passages, helps direct energy and facilitates deep concentration." Keep your inhales and exhales even to relax your neck muscles and steady your hands and feet.