If you ever find yourself in the midst of a panicked or stressed moment, check in with your breathing. If it feels shallow or strained, try taking a deep breath — no, a really deep breath.
When discussing deep breathing, we're referring to breathing from your diaphragm (the large muscle right below your lungs). When you take a truly deep breath, you are expanding the lungs, pressing down the diaphragm, and causing your abdomen to expand as your lungs fill with air. This is not only wonderful for reducing tension, but research has shown that it may also help with diseases that inhibit breathing, like emphysema.
Diaphragmatic breathing rapidly and effectively calms you down and is an immediate stress buster. For athletes and runners, it's good to get in the habit of breathing this way, since it will help you take in lots of oxygen during physical activities, hopefully preventing dizziness and nauseousness.
If you're not sure you're breathing deep enough, find out with a helpful breathing exercise.