A CK-MB test may be used as a follow-up test to an elevated CK in order to determine whether the increase is due to heart damage or skeletal muscle damage.
Scuba organizations say recreational divers shouldn't go below about 130 feet, but one Egyptian diver recently ventured a bit deeper -- going more than 1,000 feet below the ocean surface and setting a world record in the process.
The Red Cross considers nine feet to be a good depth for diving if you want to be especially cautious, but the diving area in many pools is eight feet deep. Never dive into a pool that's less than eight feet deep. If you're unsure how deep a pool is, it's best to avoid diving there. It can be hard to gauge a pool's depth just by looking. Find a pool where the depth of the water is clearly marked. In many cases there will also be a sign posted that specifies diving is permitted there.