Scuba Diving and FitnessSimon Vetterli
Scuba diving started out with a reputation of being high risk and requiring great physical strength. Those early days used rubber dry suits and flotation gear was often a military surplus Mae West life jacket. The Mae West was only used at the end of the dive to keep you afloat. Divers use pure muscle power to counter difference in buoyancy. Equipment was often heavy and bulky. Clearly not a task for a youngster or member of the “weaker sex”. In reality, it clearly was not a task for the vast majority of men either. Times have changed, new understandings of the risk of diving, and advancement of diving equipment has brought diving to a safe recreational activity even to being considered a sport. One that is available to those of average physical fitness. Some celebrities claim it a great way to get and stay in shape. Naysayers, just point out the average diver is out of shape, overweight and over 50. So, who is right? How about both!
Scuba diving only needs an average level of fitness to be enjoyed safely. No different from say walking fast. The better fit you are, however, the better you can be at diving. A fit body performs better, you do not breathe as hard meaning you are using less air, you can move for longer periods of time and your heart rate does not race out of control easily. The celebrities have it dead on that it is a great way to get and stay in shape. When you are diving you are weightless, which changes the dynamics of the forces on our body. We have the sensation of floating and we do not seem to be using much energy. Our arms and hands are basically not doing much. Most of our activity is in the chest muscles and the large muscle groups in our legs. Few divers will feel tired on a normal dive. However, once they surface, it like they are a robot and someone hit the power down switch.
Even when we are streamlined swimming underwater, we have the pressure of the water fighting us when we move forward. If you have ever moved your arm underwater standing in a pool you can sense the pressure even just below the surface. While diving that pressure is all around us – at 33 feet/10 meters it doubles – but we still need to move in it. While the air we breathe underwater enters our lungs at the same pressure as the water around our body, the lungs work on a pressure difference system. Expanding the space in our chest cavity lowers the pressure and allows the lungs to inflate. We create space by two means, expanding your diaphragm and expanding the chest. The combination of these two, allows the lungs space to expand and draw air into them. While diaphragm breathing is the most effective, most people tend to breath more with the chest. If we are breathing using our chest, it has to expand against a higher pressure requiring more work.
Scuba diving is said to burn as many as 900 calories per hours, while 400-600 calories is the range most commonly suggestion for warm water diving. There are many factors involved to determine calories burned such as your depth, the temperature of the water, your thermal protection, your fitness level and the intensity of work. While diving, you are working your core muscles as well as the large muscle groups in your legs. Additionally, The body basic functions burns energy that creates heat. The body maintains a narrow range of temperature, when measured orally is it about 98.6°F (37°C). The body increase circulation to the skin to cool the blood if it gets to high, the sweat glands help cool the skin if necessary. It the body temperature drops below normal, the blood flow to the skin is restricted, conserving heat. If that is not enough, then the body will start creating additional heat by burning more energy. In dire circumstances the body may start to shiver as a means to burn calories and produce heat.
Water has a greater ability to absorb heat then the air, so as we are diving we are losing body heat faster than if we were on land. The dive suits we wear will help slow the process however the body will still lose heat. These are the factors that lead scuba diving to be a great fitness exercise. The time we spend before and after a dive also adds to the calorie burn and requires more upper body strength that the dive itself. Shore dives can be extremely tiring to a diver that is not fit. The weight of the equipment before reaching water deep enough making it weightless can be a tiring activity.
Sadly most of us cannot dive frequently enough to where diving can be a full-time component of our fitness. The overweight divers is a testament to that. Those divers are also an illustration that they are not following a healthy lifestyle.
There is a few statistics that are not really mention often to the new diver. There is a great deal of information about general fitness and points that divers who are obese are at a higher risk of a DCS, but not much beyond that. The overweight 50+ year old divers skew the statistics some, however, heart related conditions are the third largest cause of death of divers. While we can look at fitness improving our diving and reducing our risk, we also need to see that fitness plays a role in emergency situations and being fit can avoid or lessen the impact of many of them.
The term average fitness really does not help much in understanding what it needed. The doctor will tell you one thing, a fitness coach something else, and the guy selling gym memberships will have an amazing range of stats and stories. There are many websites that feature different fitness test, some use it as a promotional gimmick. Two sites that you can use that have credibility are the United States President’s Fitness Challenge and Britain’s National Health Services. These sites will also give you a background on fitness and low or no cost suggestions to improve your fitness.
One acronym you will see is FITT, this stands for Frequency, Intensity, Time and Type. It is really a summary of what fitness training is about. When you look at the recommendations, you may find that the commitment to become fit may not be hard as you once believed. If you are training beyond the guidelines, you are training for something other than general fitness. It could be to lose weight, or improve your recreational running or even to improve your diving, however, for general fitness this is all you need. You can organize your activities at either a moderate level, one that elevates the heart rate above resting levels or vigorous activity heart rate above that for moderate levels, but you should be able to talk while exercising. A moderate physical activity is brisk walking and running would be a vigorous physical activity.
Moderate and vigorous physical activity:
- Frequency: 5+ days a week for moderate activity, 3-4 days a week for vigorous activity
- Intensity and Time: Moderate – At least 30 minutes each session (these may be broken into two 15-minute sessions or three 10-minute ones). Vigorous – 20-30 minutes per session. Each session should begin with a warm-up that could include flexibility exercises and finish with a cool-down period with some stretches at the end.
- Type: Activities that use large muscle groups (that is, arms, legs) such as walking, cycling, dancing, or swimming.
Strength, cardiovascular, and flexibility are the three key elements of fitness and all need to be address over a training week. As mentioned above the thirty minutes does not have to be continuous, You can easily work a ten minute section into your morning, another after lunch and a third before dinner, provide they raise your heart rate. Cardiovascular deal with the heart and lungs. Swimming with or without mask and fins are an excellent exercise that is also building the muscle groups we use while diving. Running or walking three times a week for 30 minutes a day is a good alternative which will help us reach a suitable level. Brisk walking and running are prime examples that you can do to improve your fitness in this category and the easiest if we are doing shorter sessions. An aerobic workout will certainly get your heart rate up. Also do not limit yourself to the traditional exercises, going out dancing if it meets the intensity and time requirements is a work out.
Strength training is the one most people avoid. It brings on nightmares of going to the gym where everyone looks like they are bulked up with steroids. To be fit you just need to tone your muscles, you do not need to bulk up. The swimming or running will help strengthen your leg muscles, what you need to work on is mostly your upper body strength and your core. If you want to avoid expensive gym memberships, there are a number of inexpensive alternatives. There are home gym equipment that will match the equipment in a gym for less than a yearly membership. Mostly you can improve your strength with some resistance bands and inexpensive dumbbells. Yard sales often have these and second hand shops will have an array of them. Body weight resistance exercises are also a proven method to built strength. These exercises uses you own body as the tool. Two or three sessions a week can help you improve your strength.
Flexibility is a key element and the first one that you will notice failing as you get out of shape or older. Flexibility can be a separate exercise period or worked int your warm up and cool down periods. While it may seem unimportant, it is one that has a great impact on your daily life
Nutrition might not be a part of FITT but it is a key element of fitness. Eat healthy meals and avoid fats and junk foods. Do not fall into the vicious circle of thinking, I worked out hard today, I can just get some fast food. Not the best way to go.
The Fit Diver
Diving can be a goal of your fitness program and if you dive frequently enough a component of it. Either way a good level of fitness helps your diving as well as your life. As you improve each of the three elements of fitness – cardiovascular, strength and flexibility – you will find that your diving is easier and more comfortable. Take one of the self evaluation fitness test and start improving your diving.