Our bodies are adapted to breathe on land, but not underwater. When diving, our respiration is affected by the surrounding pressure, limited air supply, and physical changes in the air we breathe.

In this lesson, you'll learn how pressurized nitrogen affects your mental state, how carbon dioxide affects your respiratory rate, as well as special risks that skin divers face when breath-hold diving. You'll also learn about the risks of oxygen and carbon monoxide poisoning, along with the steps you can take to prevent problems resulting from breathing these gasses.

After this lesson, you will be able to:

• Describe the effects of nitrogen narcosis.
• Explain how to prevent nitrogen narcosis.
• State the proper response to nitrogen narcosis.
• Explain how your body detects the need to breathe.
• State the importance of maintaining a slow and deep breathing pattern.
• Define the term "skip breathing," and explain why it's dangerous.
• Explain how shallow water blackout occurs.
• State the best prevention against shallow water blackout.
• List two preventative measures against oxygen toxicity.
• List two preventative measures against carbon monoxide poisoning.