What kind of fitness level do you need to be at?
Diving with PADI doesn't require someone to be an athlete, but a basic level of swimming and cardiovascular fitness is helpful for the efficient use of air and the overall enjoyment of the activity. People should be able to jog at a moderate place for 10 minutes.
To prepare yourself before a dive, it's also important to hydrate just like you would for a cardio workout. Drink water or a sports drinks during dive breaks. Getting plenty of rest and stretching beforehand will also help prevent any underwater cramping and will allow you to swim at ease.
What exercises should you do to help with diving (to aid with breathing, carrying heavy equipment etc.)?
Cardio exercises such as running, biking, and swimming help to improve overall fitness, leading to potentially lower air consumption while diving. The more efficient your air consumption, the longer you can dive.
To prepare your body even further, try resistance exercises like squats and presses to give your legs the power to kick and to easily propel yourself through the water. It's also important to stretch thoroughly after every workout to release tight muscles and prevent calf or foot cramps that can occur during dives.
Why doesn't diving feel strenuous until you get out of the water and realize how tired you are?
Because diving is a low-impact sport similar to swimming, many divers don't and should not, feel the physical exertion underwater, even though they're using major muscle groups to propel themselves through the water. Many times, divers are so immersed in their surroundings—including shipwrecks, underwater geography and marine wildlife—they don't realize their muscles are working until they are back on dry land.
More: 7 Pilates Moves for a Bikini-Ready Body
How can someone use diving as a healthy living tool to relieve stress?
Many people find that scuba diving is a relaxing experience that allows them to connect with nature and explore the world from a different perspective. While scuba diving, you breathe more slowly and deeply than you would in everyday life, which encourages your blood vessels to dilate and your blood pressure to lower, which relaxes both mind and body.
When diving, do you actually take in more oxygen than you normally do?
The air a diver breathes during a dive is made up of oxygen and nitrogen at a ratio of 21 percent and 79 percent, respectively. Water has weight, as anyone who has picked up a gallon water jug can tell you.
Air is light, and therefore susceptible to the weight of the water when you scuba dive. Without getting too involved with the physics of diving, the deeper you dive the more compressed the air you breathe becomes because of the weight of the surrounding water. So while the ratio of the oxygen to nitrogen in the mix remains the same, the percent of oxygen in each breath is higher the deeper you dive. Breathing this "thicker" air will not feel any different to the diver. For example, at 33 feet, the oxygen content is 42 percent, and at 66 feet the oxygen content of each breath is 63 percent. For this reason, people who are intolerant of breathing pure oxygen cannot become certified to scuba dive.
