|Year : 2021 | Volume
| Issue : 2 | Page : 119-124
Assessment of sea sickness in naval personnel: Incidence and management
Arvind K Gupta1, B Vijaya Kumar2, Renu Rajguru1, KD Parate2
1 Department of ENT, INHS Asvini, Mumbai, Maharashtra, India
2 Fleet Medical Centre, Mumbai, Maharashtra, India
|Date of Submission||13-Apr-2020|
|Date of Acceptance||05-Sep-2020|
|Date of Web Publication||9-Jul-2021|
Dr. Renu Rajguru
Department of ENT, INHS ASVINI, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
Background: Strategic, operational and tactical superiority of Navy hinges on extremely efficient warships which in turn depend on professionally competent sailors ready to undertake tasks to deliver timely, structured and metered response. Ships and their potentialities are tools to achieve the required strategic advantage which is dependent on the proficiency of sailors. Sailors who are fit ashore may be debilitated on board because of sea sickness. Aims: To study the incidence and severity of sea sickness among 500 naval personnel from various ships. Setting and design: An observational study conducted from May 2019 to March 2020 among 500 naval personnel from various ships of the fleet. Materials and Methods: Motion Sickness Assessment Questionnaire (MSAQ) was used to collect data from personnel of different departments working in different part of ship aged between 20 to 50 years. Results: The majority suffered mild symptoms (78.78%) and did not require any medication. Their symptoms were selflimiting and settled on rest within 24 hours. Moderately severe symptoms were observed among 19.31 % personnel and had to be administered medication and rest for 24 hours. Only 1.91% had severe symptoms and had to be excused from duties along with medication and rest. Conclusion: Sea sickness is unpleasant and has an adverse effect on employability of the sailors. It is mild and self limiting in majority of the personnel not requiring active intervention. Some personnel may require desensitisation along with pharmacotherapy.
Keywords: Motion sickness assessment questionnaire, sensory conflict, behavioral strategy, medications
|How to cite this article:|
Gupta AK, Kumar B V, Rajguru R, Parate K D. Assessment of sea sickness in naval personnel: Incidence and management. Indian J Occup Environ Med 2021;25:119-24
|How to cite this URL:|
Gupta AK, Kumar B V, Rajguru R, Parate K D. Assessment of sea sickness in naval personnel: Incidence and management. Indian J Occup Environ Med [serial online] 2021 [cited 2021 Jul 27];25:119-24. Available from: https://www.ijoem.com/text.asp?2021/25/2/119/321071
| Introduction|| |
Strategic, operational, and tactical superiority of Navy hinges on extremely efficient warships which in turn depend on professionally competent sailors ready to undertake tasks to deliver timely, structured, and metered response. Ships and their potentialities are tools to achieve the required strategic advantage which is dependent on the proficiency of sailors. Sailors who are fit ashore may be debilitated on board because of sea sickness. In critical military tasks, sea sickness would impede mission effectiveness if the naval personnel involved in important operations onboard experience sea sickness.
Sea sickness, a variant of motion sickness usually due to the roll and pitch movement of the ship, is a set of symptoms that occur in association with motion of a person or his or her surroundings, triggering a stress reaction that results in autonomic symptoms. It is characterised by various symptoms that progress through cold/hot sweating, salivation, and occasionally headache, to nausea and vomiting with incapacitation that can be severe.,
The onset of sea sickness is often insidious, with dizziness, drowsiness, and reduced alertness. It is a psychophysiological response with individual variations. For some even a minor stimulus like simply getting on board on a stationary vessel may be enough to precipitate an attack of sea sickness while others are immune to it. Some individuals may also experience “simulator sickness,” where playing complex video games on large screens or using virtual reality (VR) headsets can lead to similar symptoms even though the persons affected are not physically in motion. Military organizations of some countries like France, Israel, United Kingdom, etc., employ an operational selection for naval and air force personnel., In Indian Navy however there is no such operational selection on the basis of sea sickness.
| Materials and Methods|| |
An observational study on incidence and severity of sea sickness among naval personnel was carried out from May 2019 to March 2020. Total 500 personnel from various ships of the fleet were included in this study. All the participants were apparently healthy and medically fit. Each participant had been deployed in the sea with an average 5 to 20 deployments per year. All personnel were from different departments working in different parts of ship aged between 20 to 50 years. Motion Sickness Assessment Questionnaire (MSAQ) as attached in 'Appendix A' was used to collect data. It contained information about personal particulars, anthropometric profile, average duration at sea, and symptoms of motion sickness encompassing gastrointestinal, central, peripheral, and psychosomatic. The data were then compiled and analyzed.
| Results|| |
[Table 1] shows the mean age of personnel was 30 years with SD 8.78.
[Table 2] shows that 62.2% personnel sailed for duration less than equal to 7 days at sea, 23.6% were for duration 8 to 14 days and rest 14.2% for more than 14 days at sea.
[Table 3] showing that 31.2% of personnel were having symptoms related to central––vestibular system, 28.4% were having gastrointestinal symptoms, 23.2% were having sopite syndrome-related symptoms and rest of the 17.2% were having peripheral autonomic symptoms.
[Table 4] showing that 78.78% personnel were had self-limited minor inconvenience, not requiring any rest or medication or excuse from duty, 19.31% were having moderate symptoms requiring medication for sea sickness and rest for 24 hours, 1.91% were such individuals who had severe symptoms and required medication for longer duration along with rest and excuse from duties for more than 24 hours.
[Table 5] shows that majority 54.5% were having sea sickness of first exposure and 26.5% were had symptoms even up to 10 exposures at sea. 5.4% were such that they had continued symptoms even after more than 10 exposures at sea.
| Discussion|| |
Exposure to unfamiliar real or apparent motion at sea produces a psycho-physiological response with a complex set of symptoms affecting gastrointestinal, central, peripheral system. Once the triggering motion ceases, symptoms generally disappear completely within 24 hours.
Our study was conducted on 500 Naval personnel aged between 20 and 45 years [Table 1]. Data included anthropometry, types of symptoms with predominant system involvement, severity of sea sickness in relation to exposure and requiring medical intervention and rest or excuse from duty. In our study 62.2% personnel had sailed up to 7 days at sea, 23.6% for 8-14 days and 14.2% for more than 14 days [Table 2].
Among the symptoms those related to central nervous system (31.2%) were the most common namely dizziness, spinning sensation, light headedness, drowsiness followed by gastrointestinal system symptoms (28.4%) like nausea, vomiting, queasiness etc.
Early symptoms of incipient motion sickness with reduced alertness are also called “sopite syndrome” (from the Latin word sopire which means to lull or to put to sleep). The term describes a condition of withdrawal with increasing apathy and lethargy which the person affected may not even notice him- or herself.
In our study, 23.2% of personnel presented with sopite symptoms like feeling annoyed, irritated, drowsy, fatigue, uneasy feeling. Rest 17.2% presented with peripheral symptoms like feeling sweaty, cold, warm or hot sensation of body [Table 3].
The majority suffered mild symptoms (78.78%) and did not require any medication. Their symptoms were self-limiting and settled on rest within 24 hours. Moderately severe symptoms were observed among 19.31% personnel and had to be administered medication and rest for 24 hours. Only 1.91% had severe symptoms and had to be excused from duties along with medication and rest [Table 4].
Sea sickness on first exposure was noticed in 54.5% personnel, 26.5% personnel continued to have symptoms up to 10 exposures and 13.6% had symptoms even after 10 exposures of sea. Only 5.4% had symptoms of sea sickness each time they were sailed out [Table 5].
The scientific literature does not present a consistent picture on performance limitation due to sea sickness., It is possible for the personnel to carry out their allotted task on the ship though with discomfort if they experience mild gastrointestinal symptoms like nausea, vomiting lasting for the transient duration. However, they experience apathy and depression with a resultant decrement in performance through cognitive, emotional, and motivational deficits.
The pathophysiology of sea sickness is best explained by sensory conflict or neural mismatch theory.,,,,,,, Vestibular, somatosensory, and visual afferents provide information about body movements and body posture. The vestibular inputs are provided by the three semicircular canals i.e., horizontal, superior, posterior semicircular canals, stimulated by angular acceleration, and by the otolith organs i.e., saccule and utricle, which are stimulated by linear acceleration. Proprioceptive afferents from the neck muscles and the vertebral column maintain the position of the head relative to the torso. Visual inputs provide information on the body's own motion and/or that of its environment. The sense of joints movements, joint position, and acceleration is by proprioceptive afferents from the joints and skeletal musculature. Normally the three sensory channels (vestibular, visual, and proprioceptive) complement each other without contradiction. The afferents are connected to motor centers in the brainstem, which stabilize body position e.g., through the use of stabilization reactions. Sensory conflicts are the most current explanation of motion sickness. The conflict type is tabulated in [Table 6] given below.
The relative incidence of some of these symptoms in 10 US navy flights studied by Kennedy and colleagues confirms similar findings. Data from other studies also support these findings.,
The ways to prevent sea sickness is to avoid exposure to provocative motion exposure and adaptation. Some of the measures are hydration, fresh air, keeping sight on fixed object, suitable position in the middle of the ship and antiemetics and antihistaminics. Adaptation is the most potent prophylaxis. Various desensitization therapies are used for adaptation including stimuli like vertical linear oscillation and optokinetic stimulation in the belief that there will be a better adaptation to the dynamic environment. The desensitization therapy has been successfully used for air crew and the same can be applied to sailors too.,, Desensitization physiotherapy also includes reactive motion and body positioning exercises by actively synchronizing body movements with motion including head tilts.
Nondrug therapy for sea sickness includes behavioral strategy like habituating to motion pattern, reducing intersensory conflict, and synchronizing the visual system with the motion [Table 7].,
|Table 7: Behavioural strategies to prevent or minimize symptoms of motion sickness|
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At sea the intersensory conflict can be minimized by looking in the direction of ship movement or gazing at the horizon. Head-mounted display having an artificial horizon or horizon information will also decrease the intersensory conflict.
Medical management of sea sickness includes centrally acting anticholinergic drug-like scopolamine, which is probably the most effective, usually used as1.5 mg transdermal patch applied 6-8 hrs before exposure, it is effective for 72 hrs. Common adverse effects are dry eyes, dry mouth, and light sensitivity. Other drugs like antihistaminics have also been shown to be effective in motion sickness and they include, in ascending order of sedating potential, Cinnarizine, dimenhydrinate, diphenhydramine, and promethazine. Cinnarizine is the most commonly used antihistaminic for dizziness and vertigo due to varying pathogenesis. It is used mainly for acute episode in a dose of 25 mg thrice a day for not more than 4 – 7 days. Common side effects of its use are drowsiness, dry mouth, and stomach pain.,
Avoiding foods with high histamine content, such as tuna, some kinds of cheese, processed food and red wine might be helpful. Some natural remedies like ginger and Vitamin C to repress sea sickness are also recommended by some studies. Ginger contains certain substances that antagonize 5HT3 receptors, which has an important role in the vomiting center. High-dose vitamin C was found to reduce the symptoms of sea sickness because of some anti-histaminergic effect without identifiable adverse effects, in a prospective, double-blind, placebo-controlled study.
In some cases good response had been found by application of transcutaneous electrical nerve stimulation (TENS) and by general stress-reduction measures such as listening to pleasant music or exposure to good odours, aroma and fragrance.,,,
| Conclusion|| |
Sea sickness is a classical type of motion sickness producing a set of symptoms on exposure to environment in which there is a conflict of vestibular and visual sensory input generating a stress reaction that results in autonomic symptoms. It is observed that sea sickness is troublesome for personnel onboard deployed in operations especially young sailors on first exposure to sailing. Once the triggering stimuli disappear symptoms get controlled within 24 hours with some exceptions. These personnel can then be managed by behavioral desensitizing habituation methods in combination with drugs like H1-antihistamines and anticholinergics.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| Appendix A|| |
Motion Sickness Assessment Questionnaire (MSAQ)
Instruction – Using the scale below, please rate how accurately the following statements describe your experience during motion sickness
Not at all 1----2---3---4---5---6---7---8---9---10 severely
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]