Heart disease, which is the leading cause of death in the general population and the second leading cause in our sport, kills more divers than any other health condition, and, not surprisingly, often contributes to drowning — the number one cause of diver death. It’s not that diving is unhealthy for your heart, say cardiologists. It’s that people with unhealthy hearts stress them past their limits when they go diving.
Heart disease is a wide umbrella term that covers atherosclerosis (hardening of the arteries), as well as previous heart attacks, heart valve abnormalities, and heart-rhythm problems. Though we think of diving as fun and relaxing (and it is) cold water, pre-dive jitters, choppy surface swims, even just immersing yourself in water can raise your blood pressure or otherwise tax your cardiovascular system. Any underlying heart disease, such as hardening of the arteries, can spell disaster. Divers with heart disease run the risk of fatal heart attacks in the water, as well as nonfatal heart attacks and chest pain that can lead to panic and drowning.
Dive operators can and will deny people who've had heart attacks or report heart disease. DAN recommends waiting six months to a year after a heart attack or heart surgery before considering diving again. Then you should test your dive fitness with a stress test, where your heart function is monitored while you exercise at increasing intensity on a treadmill. DAN doctors advise that they be able to exercise up to a level of 13 METs - the equivalent of running an eight-minute-mile pace for a few seconds - without adverse symptoms. That's the sign of a healthy, dive-ready heart. You also need to be symptom-free. If you have chest pain, lightheadedness or breathlessness during exertion, you should not be diving. Blood-thinning heart medicines may require more conservative dives because they increase the risk of excessive bleeding in the case of ear, sinus or lung injuries. Stay conservative and well within safe diving limits.
Also practice heart smart behaviors:
Get a checkup: The underlying causes of heart disease — high blood pressure, unhealthy cholesterol levels, and hardening of the arteries — often have no symptoms … until it’s too late. The only way to know if you're at increased risk for heart disease (or if you actually have early stages of heart disease) is to get an exam. See your doctor to have your blood pressure and blood work (cholesterol, triglycerides, etc.) done.
Don’t smoke. Nicotine constricts the blood vessels, sets the stage for high blood pressure and further burdens your heart, especially if you light up right before a dive. The carbon monoxide in cigarette smoke hogs up space on your red blood cells and reduces the amount of oxygen they can carry, lowering your exercise tolerance (and conceivably messing up your gas exchange).
Exercise. If you can't dash down the block to catch a ride or run up a flight or two of stairs without gasping for breath or stopping for a break, your cardiovascular system is not in shape for scuba diving. Racking up just 30 minutes of exercise a day can improve your fitness, slash your heart disease risk and keep your heart strong for scuba.
For more on heart health, visit Health Tips: Diving And A Heart Attack.
