Here's why:

* Endocrine System: The endocrine system is responsible for producing and releasing hormones, chemical messengers that regulate various bodily functions.

* Respiratory System: The respiratory system is responsible for taking in oxygen and expelling carbon dioxide.

* Adrenaline: A hormone released by the adrenal glands (part of the endocrine system) in response to stress or physical exertion.

* Effect on Respiration: Adrenaline stimulates the respiratory system to:

* Increase breathing rate: More breaths per minute.

* Increase breathing depth: Larger volume of air inhaled and exhaled.

This increased oxygen intake helps the body meet the increased demands of a stressful or physically demanding situation.