Thyroid disorders are not uncommon. They include hyperthyroidism and hypothyroidism. Hyperthyroidism is a condition in which the thyroid produces too much of the thyroid hormone, thyroxin. Hypothyroidism is the opposite, a condition in which the thyroid produces too little thyroxin. Now the thyroid is a vital glad within the body and has many functions. It works to regulate body temperature, weight, heart rate, metabolism, and many other functions within the body. Because the thyroid affects so many things, it can be very detrimental to your health and wellbeing when there is a problem.
When you have hyperthyroidism, the thyroid can cause increased heart rate, affect the respiratory rate, decrease body weight, cause cardiac problems (such as an irregular heartbeat, a fast heartbeat, and heart failure), cause detrimental interaction with the central nervous system, and cause muscle weakness and possibly even paralysis. Hypothyroidism can cause fatigue, slow or absent reflexes, a slow heart rate, and slow metabolism. Heart failure is also possible.
When it comes to diving, no one who has active, untreated hyperthyroidism should dive. If a diver was underwater when the thyroid released a large amount of thyroxin, this could cause symptoms that could be debilitating to the diver. Loss of muscle strength, paralysis, heart problems; any of these could cause an emergency for the diver and possible loss of life. After all, the heart is already undergoing an increased workload with the effort of diving and if the heart becomes stressed by a spike in the release of thyroxin, then that could be catastrophic for the diver. When symptoms such as muscle weakness and tremors occur during a dive, they can be mistaken for decompression sickness, which can cause additional stress and worry for the diver.
In order for you to be sure you can dive with hyperthyroidism, there are a number of requirements that must be met. You will need an endocrinology consultation, laboratory tests need to be run, and an ophthalmological consultation will also need to be attended. When thyroid disease is present there is also a risk of ophthalmological problems, such as exophthalmos, also known as protrusion of the eyes. In fact, those divers with ophthalmological problems may not be allowed to dive while being treated and if the problem persists, may not be allowed to dive again.
Fortunately, hyperthyroidism is relatively easy to treat. Treatments include medication, radiation, radioactive iodine, and/or surgery. The amount of hormone being released by the thyroid can be determined via blood tests and once levels are reduced and stabilized a diver can resume diving. Sometimes, after hyperthyroidism is treated, thyroxin levels go down too low. This can cause problems as well, but these levels can easily be brought back into normal range with a drug called Synthroid.
When it comes to treatment with drugs such as Methimazole, there is a 50% relapse rate among patients. With radioactive iodine treatment 10% to 20% of cases will be on Synthroid medication within two years and 50% to 60% will be on it within 20 years. After thyroid surgery one third of all patients will be on Synthroid medication within ten years. As you can see, for this reason it is important that there be ongoing and frequent checks on thyroid levels in an individual who has been successfully treated for hyperthyroidism.
The medications themselves may be cause for concern when diving. If a diver is being treated for hyperthyroidism with a drug such as Methimazole, then diving may not resume until the treatment is completed as the drug can cause side effects such as vertigo, drowsiness, and even bone marrow suppression. The Synthroid medication is safe for recreational diving, but Nitrox diving is to be avoided because Synthroid increases the risk of oxygen toxicity and oxygen seizures.
It is also important to remember that divers must be in good physical shape otherwise in order to dive with a thyroid disorder. It is crucial that anyone with a thyroid disorder have their cardiovascular system checked thoroughly and have their thyroid levels checked each month for the three months prior to the dive. This way they can be sure that their thyroid is healthy and that there are no underlying cardiovascular problems that can cause an emergency while diving.
As you can see, thyroid problems pose a serious health risk when diving. It is one thing to have to deal with the symptoms of hyperthyroidism on dry land, where the person can be treated immediately and can be kept safe until the symptoms have been dealt with. However, when you are underwater and hyperthyroidism causes those unwanted symptoms this can mean death for the diver. When diving, be sure to let your dive leader and buddy know that you have been treated for hyperthyroidism and hypothyroidism too if that is the case. While it is safe for you to be diving again, it is wise the alert others so that they will be fully aware if anything goes wrong during the dive. Then you can go out and have fun doing the sport you love.