About 60% of attacks are accompanied by hyperventilation and many panickers overbreathe even whilst relaxed.

The most important thing to understand about hyperventilation is that although it can feel as if you don't have enough oxygen, the opposite is true. It is a symptom of too much oxygen.

With hyperventilation, your body has too much oxygen. To use this oxygen (to extract it from your blood), your body needs a certain amount of Carbon Dioxide (CO2).

When you hyperventilate, you do not give your body long enough to retain CO2, and so your body cannot use the oxygen you have. This causes you to feel as if you are short of air, when actually you have too much. This is why the following techniques work to get rid of hyperventilation.

Some hyperventilation and panic attack symptoms are:
Light headiness
Giddiness
Dizziness
Shortness of breath
Heart palpitations
Numbness
Chest pains
Dry mouth
Clammy hands
Difficulty swallowing
Tremors
Sweating
Weakness