Most importantly sea-sickness may also aggravate chronic illness, such as diabetes, chronic renal disease and other relevant medical conditions.

 

 

Table 2: Motion sickness: Impact on Co-morbidities. These are just a few examples of relevant medical condition, essentially any chronic or acute disease requiring medication may become affected by severe motion sickness by loss of medication via vomit, irregular drug ingestion times, or altered pharmacokinetics.

 

Co-Morbidity

Motion sickness impact

Diabetes mellitus (Type I+II, insulin-dependend)

Risk of hypoglycemia because of vomiting

Chronic renal disease (e.g. renal insufficiency)

Risk of exacerbation because of reduced diuresis via ADH-increase and dehydration

Acute/recent gastrointestial ulcerations, GI-surgery

Risk of GI bleeding via increased intraabdominal pressure while retching and vomiting

Arterial hypertension

Risk of critical blood pressure increase when retching and vomiting

Drug addiction and psychosis

Risk of decompensation (crisis)

Organ transplant

Immunosuppressive medication may become ineffective and transplant rejection flares might be triggered

Contraception

Anti-baby-pill may become ineffective, additional contraceptive method advisable until next menses.

 

 

 

Obviously vomiting poses an issue regarding loss of oral medication for acute and chronic diseases. Even low to medium grade motion sickness may impair gastrintestinal motility, resulting in an altered drug absorption, which may also put patients at risk of an insufficient medication. This is highly relevant in a number of conditions, e.g. in transplant patients depending on oral anti-rejection drugs. Severly seasick female passengers taking the pill may need to apply additional contraceptive measures for weeks until their subsequent menses.

 

 Prophylaxis of seasickness

A variety of precautionary measures and fundamental rules may help to prevent or at least to curtail motion sickness manifestations in seafarers, such as:

  • Alcohol and nicotine avoidance before and during travel
  • Maintenance of sufficient sleep and recovery time
  • Avoidance (already at planning) of nightly travels and cruises, especially at the beginning of the voyage; surely this is neither doable in cargo shipping nor on cruise ships with a tight schedule
  • Choice of cabins with bull eyes/windows in the middle or rear section, close to sea level. If anxiety regarding seafaring is involved, a cabin well above sea level may be more appropriate
  • Walking on deck at frequent intervals while fixing the horizon often is beneficial
  • Reading for longer periods should be avoided
  • One should not tilt the head forward unnecessarily
  • Sufficiently warm (but not too warm), breathable clothing is important
  • Good ventilation should be warranted, avoiding smell of e.g. diesel, toilets and cooking
  • Regular fluid intake (non-alcoholic drinks) should be maintained
  • Small meals at regular intervals, preferably proteins and carbohydrates, avoiding fatty meals and beverages with cream or fatty milk
  • Positive thinking and the deliberate acceptance of the situation of being on a voyage
  • Listening to favorite music (e.g. via MP3 player, iPod) may significantly improve the mood and may help to relieve anxiety
  • Putting on acupressure wristbands at the Nei Guan-Point [35] may also prove beneficial (Figure 3)
  • Lying comfortably in a horizontal position with eyes closed
  • Inquire about stabilizers when booking a ship cruise, older constructions may be more prone to rolling in high seas.
  • When chartering or booking berths on sailing yachts, size surely matters: The bigger the yacht the better, at least in terms of nauseogenicity of ship motions.
  • Sailing yacht hull shape influences motion patterns; yachts equipped with a heavy long keel show more steady motions compared to short-keelers. Wing-keels may favorably reduce heave motions.
  • Catamarans in general usually put less motion stress on their passengers (exception: going against in high seas may lead to stressful >slamming<)

 

Sensitive individuals should definitely consider using a medication prophylaxis:

  • Ginger-Tablets or preferably approx. 1-2 g fresh ginger root 2 hours prior to start of the voyage [36]. Putting sliced fresh ginger into hot tea (and chewing the bits afterwards) or between slices of bread makes it more pallable.
  • In case of a heavy weather forecast or if the individual has experienced severe motion sickness before, highly reliable prophylactic medication such as scopolamine patches, meclizine supp. or dimenhydrinate supp. should be administered (Table 3) in due time before departure.

 

Motion-sensitive travelers often experience anticipatory anxiety in the beginning of a cruise. Relaxation exercises such as autogenic training, progressive muscle relaxation/PMR, and biofeedback may help to alleviate anxiety and thus help to prevent or at least curtail motion sickness symptoms.

Professional airspace training programs exposing astronauts´ heads to repeated accelerations and decelerations as well as turns and rotations, are achieving some level of subsequent tolerance to motion stimuli. Regularly performing sports in general seems to have a beneficial overall effect on motion sickness susceptibility, in particular sports training proprioception (Thai Chi, Judo, etc. [37]).

A diet low in histamine content (e.g. via avoidance of fish, cheese, tomatoes, chocolate etc.) has been proposed as a prophylactic measure [39]. This may indeed make sense in patients with proven deficiency of histamine degrading enzyme (Diaminoxydase, DAO), however no clinical proof has been provided in healthy sailors. This measure may even be detrimental, since some of the food quoted (cheese, chocolate, meat) also is a major source of tryptophane, and tryptophane ingestion may reduce susceptibility to motion sickness [20].

Recently a study by Greek investigators found an association between Helicobacter pylori eradication treatment of aviators and an increase in their motion stimuli tolerance (number of habituation flights), thus treating motion sensitive H.P.-positive personnel may provide an additional prophylactic measure [39].

An effective prophylaxis against seasickness is of utmost importance in case of distress at sea, in particular shipwreckingas soon as possible before passengers and crew start to embark on rescue vessels such as life-rafts or totally-enclosed motor-propelled survival craft (TEMPSC). Given the extreme movements of a small raft in heavy seas even experienced sailors may get seriously seasick within a short period of time, making them prone to loss of fluid and putting them at an increased risk of going over board of the raft. Motion sickness may also aggravate loss of body heat in immersion, thereby promoting hypothermia and reducing survival times in naval accidents [1;2]. Therefore a scopolamine patch or a dimenhydrinate- or meclizine-suppository should be administered to each passenger in due time before entering a life-raft or rescue shuttle (as soon as the necessity to abandon ship becomes obvious). A recent publication [[vi]] suggests that antihistamines such as dimenhydrinate may be more beneficial regarding core cooling than scopolamine, as shown in an experimental setting. However further evidence may be required before a specific advice can be given and a potential benefit may be set off by a lower responder rate to dimenhydrinate when compared to scopolamine. In general, practical survival training and good leadership seem to play a very important role in the amelioration of seasickness in such emergencies [41].

 

In case of full-blown motion sickness symptoms (moderate malaise A or worse, see table 1a) occurring early despite precautionary measures, one should readily initiate appropriate treatment (always check for contraindications and caveats first) – (see 10.13.6 Treatment and Table 3).