How to Prevent Seasickness

While the subject of seasickness may not be the most appealing topic, it is one that does need to be addressed as much of the snorkeling that is done in the world is via a boat or some form of water craft. Seasickness is not something new as references to it have been attributed to Hippocrates (460BC-370BC) who has been called the father of medicine. The word seasick originates from the Greek word ναυτιών with ναυ meaning mariners and τιών meaning price. In essence this was the price that was paid for traveling on the sea. The words carsick, seasick and airsick may sound as if they are different maladies but they all fall into the category of motion sickness with the only difference being the mode of transportation on which the motion sickness occurred. Travelers may have also heard seasickness referred to by the French name 'mal de mer' which may sound a little more glamorous but in reality it is still seasick.


To understand the causes of motion sickness, one has to understand that movement or the sensation of movement is a function of the brain which involves receiving information via three different pathways, all of which are a part of the human body's central nervous system. The signals received by the brain originate from the inner ear, the eyes as well as the deeper tissues of the body surface and this information is interpreted, coordinated, combined and either accepted or rejected. It is hypothesized that if one or more of these signals conflicts with what the brain deems as acceptable information, it's reaction is what is thought to be responsible for the effects of sea sickness.

  • The inner ear governs hearing but also helps us to maintain our balance by way of the cochlea and semicircular canals which are filled with a water-like fluid. The semi circular canals sense physical movement, acceleration and gravity.

  • Our eyes play a very important role in allowing us to maintain our balance by providing visual input as to our surroundings. The images that are seen by the retina allow the brain to discern spatial differences which might need different body positioning in order to maintain equilibrium.

  • The  Deep Tissue receptors (proprioceptors) are tasked with letting the brain be aware of what part of the body they belong to, which allows it to monitor the proper joint and limb positions that are needed in order to remain balanced.

Most of the information that the brain receives from these three areas does not really require conscious thought with regard to how the body maintains equilibrium. The brain processes this information in the background without really disturbing other brain processes. Examples of what the brain may deem as unacceptable information with regard to seasickness may be as simple as walking below the deck of a rocking boat. When the boat rocks our ears may register the rocking motion but our eyes are sending signals to the brain that show everything at a normal point of view. If the rocking motion is more pronounced, the eyes may register a tilted perspective with the ears sensing otherwise. The brain tries to compensate to adjust the limbs but before it can finish the process the boat rocks the other way and changes everything once again. People who are on the sea a lot may develop what is called their "sea legs" which simply means that their brain has been able to adjust and compensate to the spatial differences.

It is estimated that 33 percent of the world population is susceptible to seasickness while on a boat in waters that are relatively calm. The percentage does jump to nearly 66 percent if the water conditions are more severe. The symptoms of motion sickness vary based on the individual and while none of them are usually life threatening, can range from mild to severe. The mild symptoms can include headache, a mild feeling of unease and yawning whereas more serious symptoms could include drooling, drowsiness,sweating, feeling short of breath, dizziness and vomiting. If you are prone to motion sickness there are ways that to prevent the onset of symptoms. While these are not a guarantee of prevention, they have been known to help.

  • Avoid overeating prior to boarding. Being full to the point of discomfort will only magnify the feeling when you are on board. Chew the food that you do eat well before swallowing. The digestion process is a lot of work for the body and wolfing down your food will can lead to excess stomach acid and indigestion. Another reason for this is if vomiting does occur ...well you get the idea.

  • Alcohol consumption does have an affect on equilibrium and can contribute to the onset of seasickness. While it is more common to celebrate your vacation by imbibing, if you get on the boat with a hangover, you will end up paying the price for  doing so.

  • If you know that you are somewhat prone to seasickness, it is a good idea to arrive at the dock with time enough to request to board and stow your gear before others. Most snorkeling boats have storage space beneath the seating areas where the passengers will sit. Choose your spot so that it is more toward the middle of the boat as that is the area with the least amount of pronounced movement. Once your gear is stowed get off the boat and remain on the dock waiting until the very last minute to board. With regard to choosing your seating location, it is a wise idea to stay away from where the exhaust fumes from the engines are prevalent.

  • Remain busy while you are underway as it occupies your mind and keeps you from thinking about becoming seasick.

  • Remain on deck and avoid going into the cabin portion of a boat if it is so equipped.

  • If possible, focus on some stationary object along the shoreline and if nothing is available, focus on the horizon.

  • When you arrive at your destination, be prepared to be one of the first few to get into the water. This really does help.

  • Acupressure points which has it's history based the ancient Chinese healing art may also work for you.  This involves applying pressure to key points of the body. In the case of seasickness, the pressure point is located in the wrist area. There are wristband that are sold commercially that are often used for this type of prevention.

  • Over the counter and doctor prescribed medicines are also available. With respect to the over the counter medications, you should always check with a physician who is versed in your medical history before using these. Read and follow all directions and note any warnings associated with such medications before use. If it is approved by your physician, the medicine should be tried before the trip to make sure of your body's personal reaction to it. If you think that taking the medicine just prior to boarding the boat is going to be enough time for it to work, you would be wrong. Medicines need time to accomplish what they are meant to do. It is almost a guarantee that popping a seasickness pill right before getting on the boat will have you seeing that pill again shortly.

Even though seasickness is not contagious, it is a common occurrence that when one person begins vomiting, others may also join in. This is thought to be an evolved trait passed down from the primates as sort of a survival trait. If a group were eating and one member had an adverse reaction to what was being eaten and began vomiting, this might cue the others that maybe what they were eating was not good and they would in turn vomit to expel the food. It is a bit strange to think of it in this way but it does make sense. If there is anything good to say about vomiting in relationship to snorkeling, it would have to be that it sure attracts a lot of fish.

Call it what you will sea sickness is a reality with a great number of people but for many it is manageable and should not preclude a person from snorkeling. Many of the tips presented in this article have been passed down from generation to generation quite probably from people who were prone to seasickness. For those that may have experienced the more severe symptoms of seasickness and have vowed never to step on a boat again there is a lot to see while snorkeling from the shore.

Medical News Today
The Physics Classroom