High blood pressure, otherwise known as hypertension, is one of the most common medical conditions seen in the general population and in the diving population as well. Hypertension can result from a number of things, including a narrowing and hardening of the arteries, which restricts blood flow and increases the pressure of the blood on the vessel walls, thyroid dysfunction, adrenal gland dysfunction, kidney problems, or a hormone imbalance. Blood pressure is measured by two numbers, the systolic pressure and the diastolic pressure. For normal blood pressure, the systolic pressure should be under 140 and the diastolic pressure should be under 90. Blood pressure is generally given by stating the systolic pressure over the diastolic pressure, such as 120 over 80.
When a person has hypertension, there are two main risks. One of these is the short-term risk of a stroke due to blood vessel rupture in the brain, which is called a cerebrovascular accident. The other is the long-term risk of coronary artery disease, congestive heart failure, eye problems, kidney disease, and cerebrovascular disease. The long-term risk is the most likely to occur of the two and the long-term risks are very common in the general and diving population, but all of these risks are dangerous for the diver.
So can a diver with hypertension dive? Essentially, once the blood pressure is brought back into normal range with the use of medication and is under control, the person can resume diving. The only concern is that of possible side effects from the medications that are used for controlling high blood pressure. However, if the hypertension is mild, it may be controlled simply with diet and exercise, which is the ideal situation. There are a number of drugs that are used to treat hypertension and these have varying side effects, depending on which ones are taken and whether they are taken alone or in combination with other drugs. The most commonly used drugs are beta-blockers, calcium blockers, angiotensin converting enzyme (ACE) inhibitors, and diuretics.
No matter what, anyone who has hypertension or who is being treated for it should be examined regularly for the development of heart disease. Any conditions of heart disease pose additional risks to divers and must be treated before a person can resume diving. Signs of heart disease should be looked for and the heart should undergo an exercise stress test regularly to ensure that it is strong enough to withstand the physical demands of diving. A patient's cardiovascular fitness and health should be monitored on an ongoing basis. It is also important to monitor for signs of end-organ damage and kidney health while being treated for hypertension.
Now a word on hypotension, which is low blood pressure. The numbers of low blood pressure are not carved in stone as it varies with the individual. However, this is certainly not nearly as dangerous as high blood pressure and most people can dive when they have hypotension. This is because there is a blood redistribution in the body while underwater and there is virtually no risk of the effects of gravity, which can cause dizziness, obnubilation, and even unconsciousness with changing from a sitting position to one of standing. So the general rule is that if your low blood pressure does not affect your performance on land, you should be fine to dive. It is important to ensure you have good cardiovascular health and should undergo a heart stress test regularly. It is important to keep your levels of hydration and electrolytes up as well. Paying close attention to these, especially during hot weather is important to your overall health as hydration and blood salt content are related to blood pressure.
If you have hypertension or hypotension, then rest assured that this is a condition that is common and easily treatable. Just be sure to get the treatment you need and consult with your doctor before returning to diving. If you are new to diving, then be sure that all is in order before you begin. After all, you want your diving time to be relaxing and fun, not a time when you will be worrying about your health and wellbeing in the water. So get out there and have some great fun in the big blue sea, knowing your blood pressure is under control.