Diving normally doesn’t take a lot of energy or physical exhertion, however there are times when you may need to swim through strong currents, dive in very cold water or assist another diver.  When those situations arise, you need to be sure that your level of fitness will meet the demands of the situation.

A recent research study conducted by DAN showed that 26 percent of all diving fatalities over a 10-year period were caused by cardiac events.  In a separate study, 48 percent of the divers who died over a three year period were found to have a body mass index (BMI) greater than 30.  If you didn’t know, a healthy BMI is between 19 and 24….so 30 places a person in the obese range.

Your BMI is only one factor in assessing your overall fitness level.  A stress test conducted in an exercise lab is the most accurate way to assess your fitness level, however that is rarely available to the average person.  An alternative to a full stress test is to calculate your overall fitness level by determining your exercise capacity. You can obatin that type of measurement by calculating a Metabolic Equivalent of Task or MET.

MET or the standard metabolic equivalent is a unit used to estimate the amount of oxygen used by the body during physical activity. 1 MET = the energy (oxygen) used by the body at rest, while sitting quietly or reading a book, for example. The harder your body works during the activity, the more oxygen is consumed and the higher the MET level.

Many physicians believe the ability to achieve a rating of 10 METs is adequate for the average diver.

So how does one calculate their MET or METmax value?  The University of Houston created a tool called the University of Houston Non-Exercise Test for Predicting VO2max.  This tool can help you determine your exercise capacity by estimating your level of physical activity and comparing it to your age and your body mass index.  You can use this tool to calculate your VO2max, which can then be used to determine your METmax.

Ensuring that you are fit and able to handle the demands of your planned dives improves the safety of the dives.  A secondary benefit is that you will likely use less air, therefore being able to extend your bottom time.

You can download a copy of the tool from here.

When you first start diving, one of the first questions you will likely have have is…."What equipment do I need to buy?" or "What equipment should I buy first?".  While there’s no single answer to those questions, the answers will partially depend on how frequently and where you will be diving.

The equipment you can, or will, purchase over time includes the following. As you start to investigate specific pieces of equipment, you will quickly realize that some of the items can be relatively expensive.  Dive shops and resorts will have this equipment for rent (with the possible exception of dive computers), but as you progress as a diver, you will likey want to purchase at least a few pieces of equipment of your own.  I have listed some of the major pieces of equipment below, based on priority of purchase…but this is just my personal opinion .

• Mask & snorkel
• Fins
• Dive Log Book
• Exposure Protection
• Dive Computer
• Regulator
• Instrumentation/Gauges
• Buoyancy Compensation Device (BCD)
• Weights
• High Pressure Compressed Gas Tank
• Knife, signaling devices, etc

Read the rest of this entry »

The amount of weighting that you will need to remain neutrally buoyant will varying based on a number of factors.  Water salinity (fresh vs salt), type of exposure protection and body type are just a few.  As you gain experience and log additional dives in your log book, you can refer to your previous dives to begin gaining an understanding of what your typical weight requirements are based on the planned dive.  Prior to gaining that level of experience, you can get a good estimate of your weighting requirements by using the following guidelines.

These guidelines assume you are diving in salt water and are of an average physical build.  If you have a leaner build, you can decrease the weighting slightly, if you are heavier, you should increase it slightly.

Read the rest of this entry »

Simply amazing….diving to 300 feet, without the use of fins, on a single breath of air!

Vertical Blue 2010: Record Breaking Dives

I think this is just incredible.  The ability for these types of divers to control their bodies and breathing for this long blows my mind.  I doubt he could hold it that long when actually swimming, but even being able to stay underwater for half that long while snorkeling would be very fun.

Link to full article.