Coffee won't cure that late afternoon slump (blasphemy, I know). Instead of yawning at your desk, use your breath as a substitute for your next shot of espresso. Sit up straight in your desk, feet firmly planted on the floor and inhale and exhale rapidly through your nose, keeping your mouth closed but relaxed. Your breaths in and out should be equal in duration, but as short as possible. Try for three in-and-out breath cycles per second. Disclaimer #1: This is a noisy breathing exercise so you may want to take it somewhere private. Disclaimer #2: Don't do this for more than 15 seconds on your first try or you might pass out (which is counterproductive if you're trying to stay awake). Slowly increase your time by five seconds or so every time you tip into zombie zone until you reach a full minute.

Running jostles your internal organs -- including your diaphragm -- up and down. If you're gulping for air as you hit your second mile, it can trap air in your diaphragm and cause it to spasm. The result? Painful stitches and cramps. To prevent those annoying jabs, try changing the pattern of your inhale and exhale ratios to three steps per exhalation and two steps per inhalation. This pattern ensures that the foot hitting the ground when you breathe out alternates between left and right, keeping your diaphragm even while you run.

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.