Carbon dioxide (CO2) is a gas the body naturally produces as waste. We breathe in oxygen (O2) to fuel organs and tissues and the end product is CO2. The balance between these two gases is required for a healthy body. However, when we rebreathe CO2 it can have harmful and sometimes dangerous effects on the body. When CO2 levels are elevated in the body it is known as hypercapnia. Hypercapnia can occur for a number of reasons, one of which is rebreathing our own exhaled CO2. Rebreathing CO2 can lead to increased blood pressure, headaches, muscle twitches, rapid heart rate, chest pain, confusion, and fatigue. In extreme cases, if left untreated, hypercapnia can lead to organ damage and even have long standing effects on the brain.