Whether you’re spotting playful dolphins, exploring coral reefs, or witnessing the incredible behavior of marine life in its natural habitat, scuba is an experience like no other. However, scuba can also pose certain health risks and safety hazards that require careful planning and preparation to ensure your enjoyment of the underwater world.

For centuries, humans have dreamed of exploring the oceans. Stone carvings show ancient Greeks using water reeds to see beneath the surface, and Alexander the Great reportedly experimented with a diving bell. It wasn’t until Jacques Cousteau developed the first self-contained underwater breathing apparatus (SCUBA) in 1942 that people could finally explore the underwater world safely.

The basic scuba equipment includes a tank that holds compressed air or nitrox (mixed gas) for diving, a dive mask and snorkel to allow you to see underwater, fins to help you move through the water, a BCD to provide buoyancy control, a dive computer to monitor depth and time underwater, and weights to sink to your desired depth. Depending on the type of dive, you may also use a wetsuit or dry suit for warmth and protection from debris or hazardous materials.

The most serious scuba-related medical issue is decompression sickness (commonly known as “the bends”). DCS occurs when nitrogen bubbles liberate from body tissues during a rapid ascent to the surface. These bubbles can block blood flow to your lungs and brain, resulting in symptoms such as chest pain, joint or muscle problems, and trouble breathing. Those with severe DCS can suffer coma or even death.