Research demonstrates that breathing through the mouth rather than the nose adds to the stresses placed upon a diver, because the diver already has to work harder at simply breathing through a regulator. This is called the “work of breathing.” When we add the additional physical stress of breathing gases, psychological stresses, i.e., feeling of shortness of breath or breathlessness, appear as well. Cold temperatures also increase the energy costs associated with oxygen utilization throughout the body. Respiratory limitations of divers at depth may require increased respiratory rates. Finding a healthy heart workout for divers is key to alleviating these stressors.
On land, the limiting factor to the amount of work that a body can do is usually the cardiovascular system or the heart. Underwater, the limiting factor is probably the respiratory system, so divers who maintain a good level of cardiorespiratory fitness reduce the risks associated with scuba diving and improve overall diving performance. The purpose of cardiorespiratory fitness is to maintain and improve the efficiency of the heart, lungs and vascular system. Cardiorespiratory fitness is achieved through aerobic exercise.
A Healthy Heart Workout for Divers
Based on a review of reported medical conditions by scuba divers, heart disease, cardiovascular illness and high blood pressure are the most prevalent health concerns. The good news is that aerobic exercise helps to prevent heart disease, high blood pressure and high cholesterol, and may help repair the damage from smoking.
It’s easy to understand why aerobic exercise is a necessary fitness component for scuba divers. Positive results of an aerobic program, such as easier execution of daily activities, are apparent within weeks. However, the benefits of aerobic exercise diminish dramatically in as little as two weeks of inactivity. The best results are achieved when aerobic exercise is performed consistently as part of a healthy lifestyle.
Aerobic exercise is any activity that creates and utilizes greater oxygen demand by moving primarily the large muscles of the body, repeatedly and rhythmically, at a particular intensity beyond the usual activity of rest or relaxation. Examples of aerobic exercise are walking, jogging, running, swimming, rowing, cycling, jumping rope, aerobics classes and dancing. Aerobic exercise may be performed outdoors almost anywhere; fitness centers and gyms provide plenty of equipment such as treadmills, stair climbers, ellipticals and exercise bikes as well.
The American Heart Association (AHA) recommends moderate-intensity aerobic activity at least five days per week for at least 30 minutes for a total of 150 minutes; or at least 25 minutes of vigorous aerobic activity at least three days per week for a total of 75 minutes; or a combination of moderate- and vigorous-intensity aerobic activity and moderate- to high-intensity muscle-strengthening activity at least two days per week for additional health benefits. For lowering blood pressure and cholesterol, the AHA recommends an average of 40 minutes of moderate- to vigorous-intensity aerobic activity three or four times per week. As divers, our sport may not be aerobic, but participating in a healthy heart workout will help keep us fit both on land and underwater.