>As the human body ages past its prime in the 20s, skeletal muscles begin to change. The most obvious and visible changes are diminished strength and a loss of lean body mass. This is called sarcopenia, a Greek word meaning "vanishing flesh." Age-related decline in muscle mass begins around age 25. Approximately 10 percent of muscle mass is lost between ages 25 and 50, and an additional 40 percent is lost between the ages of 50 and 80. Recent evidence demonstrates that strength training with progressive resistance may limit, reduce or even reverse these undesirable physiological effects. Progressive resistance training has been shown to yield extreme strength gains in people up to age 90.
>A strong core is important for most in-water movement. On land we tend to push off the ground, but in water the axial skeleton (the head, neck and trunk) is the most stable element in both upper- and lower-extremity movement. Partial plank exercises are a great way to build core strength. They're quick, they don't require any equipment, and they target multiple muscle groups simultaneously.
>Start by lying face down on a soft surface with your knees bent. If desired, place a folded towel under your knees or perform the exercise on a carpet or mat. Some people may even prefer to start on a bed. Although this might feel silly, a mattress is easy on the knees. Place your hands under your shoulders, and press up while maintaining a neutral spine. The most important feature of this exercise is not the movement or the time spent holding the position, it's maintaining good form.
>Partial Plank and Traveling Partial Plank
- Lie face down with your knees bent.
- Place your hands under your shoulders.
- Extend your elbows and hold for 10 to 30 seconds while maintaining a neutral spine.
- While in partial plank position, slide your right hand to the right. Next, slide your left hand to the right, move your right knee to the right, and, finally, move your left knee to the right.
- Repeat, and then travel back to the left.
>Another benefit of strength training is that it can help maintain bone density. As we age, our bones' calcium content and strength decrease. Reduced bone mineral density is known as osteopenia or osteoporosis, depending upon the degree of bone loss. Research shows that weight-bearing activities such as strength training can maintain or increase bone density when the training takes place two or three times per week. Strength training is a useful tool for men and women of all ages, and the benefits seem to increase with age. The greatest benefits come from axial (vertical) loading of the skeleton.
>The quarter squat is a highly efficient scuba-specific exercise. It targets multiple large muscle groups evenly and simultaneously. The movement mimics standing up from a seated position in full scuba gear. Improving your ability to do this exercise will minimize predive effort, saving you more energy for your dive. The movement's limited range of motion allows you to increase the resistance (using dumbbells or a backpack, for example) without breaking form. This maximizes muscular benefits and further promotes increased bone density. It is important to focus on form rather than load or resistance.
- Flex your hips and knees simultaneously about 45 degrees. Tip: Point your eyes to the sky, and put most of your weight on your heels.
- Extend your hips and knees to a standing position. Tip: Don't lock your knees; keep them slightly bent. >
>Endurance training is another great way to turn back the hands of time. Aging is typically associated with a higher resting heart rate, higher blood pressure and a decrease in the heart's maximum pumping capability. Endurance exercise has been shown to reverse all three of these undesirable effects while also keeping the arteries flexible, improving the sensitivity of blood-pressure control systems, protecting the body's metabolism (burning calories) and lowering blood sugar. Moderate (40 to 60 percent of your sprint speed) aerobic exercise such as walking, jogging, cycling or swimming for 20 to 40 minutes two or three times per week has even been shown to reduce the risk of upper-respiratory-tract infections. This may mean you're less likely to have a cold during your dive vacation.
>Swimming is an excellent endurance-training choice for divers since time in the water may improve comfort while diving. Swimming minimizes loading on the joints and has been shown to decrease blood pressure by almost 10 percent in middle-aged adults. Regular aerobic exercise also promotes cognitive function, especially later in life. Many studies have shown that exercise supports overall brain health, improving learning and memory, combating depression and protecting against several types of dementia. Among the many other benefits of endurance training are improved sleep, a better state of mind and improved reflexes.
>Take comfort in the fact that chronological aging does not mean we are destined to become frail and weak. Age-related declines in human performance are largely the result of sedentary living; a combination of strength training and endurance training with a focus on flexibility and balance will reverse age-related declines. It is never too late to start a regular exercise plan with all these components, and the benefits of each are more pronounced with age. The key to keeping your body young is to progressively challenge it to some degree most days of the week. Remember, it is not your chronological age but your physiological age that will determine your quality of life and continued enjoyment of diving for many years to come.
>DAN Note: To avoid an increased risk of decompression sickness, DAN® recommends that divers avoid strenuous exercise for 24 hours after making a dive. During your annual physical exam or following any changes in your health status, consult your physician to ensure you have medical clearance to exercise.
>© Alert Diver — Fall 2012