What is the maximum ascent rate that divers should not exceed during normal diving activities?

The maximum ascent rate that divers should not exceed during normal diving activities is 30 feet per minute. This rate is established to help prevent decompression sickness, often referred to as "the bends." When a diver ascends too quickly, the pressure surrounding the body decreases rapidly, which can lead to the formation of nitrogen bubbles in the bloodstream and tissues. These bubbles can cause serious medical issues, including varying levels of pain and potentially life-threatening conditions.

Ascending at a controlled rate allows the body sufficient time to decompress and for excess nitrogen to be safely released from the tissues back into the lungs, where it can be exhaled. Divers are taught to maintain a steady ascent rate and often recommend a safety stop at around 15 feet for three minutes after ascending to a depth of 30 feet or more. This practice further enhances safety by allowing for additional nitrogen off-gassing.

By adhering to a 30 feet per minute ascent rate, divers can minimize their risk of decompression illness while ensuring a safer dive experience overall.