1) Overactive Thyroid especially if you have weight loss, racing heart/palpilations or sweating.
2) Low progesterone and estrogen. It can be seen in woman approaching menopause, and can occur 5-12 years before periods stop and tests for menopause become positive.
3) Low testosterone in men especially beginning in or one's late 40's
4) Adrenal gland fatigue, suspect if you get irritable when hungry or sugar crave.
5) Suppressing feelings if you are in anger/ fear is buried, so you are not aware of it, it will come out as hyperventilation.
This is associate with panic attacks with intermittent inability to take a deep enough breath, numbness and tingling around your lips and in your fingers, and feeling like you are going to die. Though Scary, it is not dangerous.
Natural Cures for Anxiety:
1) Walk in sunshine : increase your exercise (especially walking in the sunshine). This is a great stress reliever.
2) Avoid Sugar and Caffein while green tea is okay.
3) Take B Complex vitamin, such as B1, B3,B5 and B6 vitamin.
4) Take magnesium, it works as anti-stress mineral as it relaxes muscle and relieves tension.
5) Theanine which comes from green tea is another source of outstanding treatment for anxiety.
6) Express your anger in a good way.
Thats all, hopes that helps a lot.