Breath-holding is the practice of intentionally stopping breathing for a period of time. This can occur naturally, such as when someone is startled or underwater, or it can be practiced deliberately for various reasons, including relaxation or meditation. The body has a natural response to hold its breath, which can trigger a feeling of calmness or focus. In some activities, like free diving or swimming, breath-holding is essential for performance. Athletes often train to increase their lung capacity and improve their ability to hold their breath longer. However, prolonged breath-holding can lead to risks such as hypoxia, which is a deficiency in the amount of oxygen reaching the tissues.