In scuba diving what is a bender?

Answer 1

We're On A BenderAs a long time Scuba diver, I'm tempted to say that a bender in scuba is just like a bender anyplace else. You've had a particularly bad day diving so that night you go out and tie one on with your dive buddy. What Are The Bends?I suspect you meant to ask "What are 'The bends'?"

"The bends" is a slang term for decompression illness. The term arose, no doubt, because one of the symptoms of decompression illness is severe muscle cramps, often causing the sufferer to involuntarily "bend" over.

When a diver descends, the gasses he breathes are delivered at higher and higher pressure. Under this increased pressure, the gasses that aren't metabolized, called "inert" gasses, are dissolved in the diver's blood stream and body tissues. For divers breathing air, the primary inert gas is nitrogen, since air is composed of about 79% nitrogen and 21% oxygen. The deeper the dive, and the longer the time at depth, the more nitrogen is dissolved into the body tissues.

Plop Plop Fizz FizzThis isn't generally a problem until the diver begins to surface. If the diver ascends slowly enough, the nitrogen is allowed to come back out of the blood and body tissues at a molecular level, just as it was absorbed, and there's no problem. If the diver ascends too quickly, however, the nitrogen can come out of solution more violently, forming micro-bubbles.

We've all seen the carbon dioxide coming out of solution in a carbonated soft drink. That's not something you like to have happen in your body tissues. Severe decompression illness is analogous to shaking the soda can or opening it in the mountains. LOTS of bubbles.

In the case of decompression illness, the tiny carbon dioxide bubbles do two things: As the bubbles form around capillaries they tend to block access of oxygen to the cells, including nerve and muscle cells. This oxygen deprivation can cause cell death which is very painful and can leave lasting damage. More severe off-gassing of nitrogen can actually cause tissue damage by perforation of cell membranes.

The obvious way to prevent decompression illness is to either ascend slowly enough that no micro-bubbles are allowed to form, or to limit the amount of nitrogen saturation that can occur by limiting dives to shallower depths for shorter durations.

Long, deep dives can cause so much nitrogen saturation that a diver is unable to ascend directly to the surface and must instead stop at prescribed depths to allow body tissues enough time to release their nitrogen slowly. These "decompression stops" are not considered safe practice for recreational divers, which is why recreational divers are limited to depths shallower than 130 feet. Diving deeper than that while breathing air requires mandatory decompression stops.

The US Navy and other military organizations developed the first "dive tables" as guidelines to determine safe bottom times for various depths. All recreational dive training agencies publish tables based on either the US Navy tables or commercially developed tables as guidelines for how long it is safe for a diver to stay at various depths without unacceptable risk of decompression illness.

Digital DivingMore recently, small dive computers, usually worn on a diver's wrist or attached to a gauge console, have been developed to assist in this function. A dive computer is programmed with algorithms that simulate the on-gassing and off-gassing of various tissue groups throughout a dive (and across sets of multiple dives). Since the computer is exposed to the same pressure changes the diver is, it is able to predict with a fairly high level of accuracy, safe bottom times and rates of ascent -- thereby avoiding "the bends".