Many runners experience shortness of breath. It's not a bad thing. In fact, it's supposed to happen in certain circumstances, most commonly if you're running faster than your body is conditioned to go, or if you're just starting out on a run.
Whether you're a beginning runner or in the middle of marathon training, there are ways to optimize your breathing. If you don't get enough oxygen to your muscles, they can't burn fuel. The more efficiently your body can extract oxygen from the air and transfer it to your muscles, the easier your running will feel at any speed.
Follow these tips to breathe easy:
1. Don't be embarrassed. I've had many runners tell me they intentionally taught themselves to breathe slowly so no one would know how out of shape they were. Meanwhile, they were killing zillions of brain cells. Breathe hard if you need to, and commend yourself for simply getting out there. The more you run, the easier your breathing will become.
More: Breathing Tips for New Runners
2. Build aerobic capacity. When you're just starting a running program, you can expect to be out of breath. Your body is using muscles it doesn't usually use, and those muscles are not equipped to take in the additional oxygen needed to sustain the increased workload. The best way to increase your aerobic capacity is by doing LSD (long slow distance) runs once a week. Run your LSDs at a comfortable, conversational pace. This type of running triggers your body to produce more extensive "capillary beds" in your muscle tissue so they can take in oxygen at a higher rate.
Nose-breathing is a great way to see if you're running at an aerobic pace. Exhale and inhale only through your nose, and if you have to open your mouth to gasp for air, you're running too fast.