Ascent Rate — What It Is and Why It Matters
Ascent rate is the speed at which a diver travels upward during the ascent phase of a dive. The universally accepted maximum safe ascent rate for recreational diving is 9 to 18 meters per minute (30 to 60 feet per minute), depending on the training agency. Most dive computers use 9 to 10 meters per minute as the warning threshold and will alarm if you exceed it.
Ascending too fast does not allow dissolved nitrogen to off-gas safely through the lungs, increasing the risk of bubble formation and decompression sickness. A slow, controlled ascent is one of the most important safety practices in diving. Many dive computers display a real-time ascent rate indicator — often as a bar graph or color-coded warning.
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Frequently Asked Questions
What is the correct ascent rate?
Most training agencies and dive computers recommend no faster than 9 to 10 meters per minute (30 feet per minute). Some agencies allow up to 18 meters per minute (60 feet per minute) from deeper portions of the dive, slowing to 9 meters per minute for the last 10 meters. When in doubt, go slower. Your dive computer will alert you if you are ascending too fast.
What should I do if my computer shows a fast ascent warning?
Immediately slow your ascent or stop ascending. Dump air from your BCD if buoyancy is causing an uncontrolled ascent. Pause for 10 to 15 seconds to let your ascent rate stabilize, then continue ascending slowly. Do not skip your safety stop — if anything, extend it after a fast ascent.
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