Vessel motion thresholds for maintaining physical and cognitive performance: a study of naval personnel at sea

Oxidative stress and motion sickness in one crew during competitive offshore sailing

Competitive Offshore Ocean Sailing is a highly demanding activity in which subjects are exposed to psychophysical stressors for a long time. To better define the physiological adaptations, we investigated the stress response of subjects exposed to 3-days long ocean navigation with disruption of circadian rhythms. 6 male subjects were involved in the study and provided urine and saliva samples before setting sail, during a single day of inshore sailing, during 3-days long ocean navigation, and at the arrival, to measure oxidative stress, cortisol, nitric oxide metabolites (NOx) and metabolic response. Motion Sickness questionnaires were also administered during the navigation. The crew suffered a mean weight loss of 1.58 kg. After the long navigation, a significant increase in ROS production and decrease in total antioxidant capacity and uric acid levels were observed. Lipid peroxidation, NO metabolites, ketones, creatinine, and neopterin levels were also increased. Furthermore, a significant increase in cortisol levels was measured. Finally, we found a correlation between motion sickness questionnaires with the increase of NOx, and no correlation with cortisol levels. Physical and psychological stress response derived from offshore sailing resulted in increased oxidative stress, nitric oxide metabolites, and cortisol levels, unbalanced redox status, transient renal function impairment, and ketosis. A direct correlation between motion sickness symptoms evaluated through questionnaires and NOx levels was also found.

Effects of control-to-display gain and operation precision requirement on touchscreen operations in vibration environments

Touchscreen has gained increasing popularity. However, little is known about touchscreen use in vibration environments. This study aimed to examine the effects of control-to-display gain (GAIN) and operation precision requirement on touchscreen operations in varied vibration environments. Twenty participants attended an experiment where they were instructed to perform three types of basic touchscreen operation tasks in static, low vibration, and high vibration environments, respectively. Five GAINs (0.75, 1, 2, 3 and 4) and three operation precision requirements (90%, 95%, and 99%) were examined. The results indicated that vibration exerted adverse effects on task performance, and increased perceived workload, perceived task difficulty and discomfort. Task completion time showed a U-shaped curve as GAIN increased. Lowering operation precision requirement improved task performance and reduced perceived workload, especially in vibration environments and at larger GAINs. The findings provide practical implications on the design of usable touchscreen interfaces in vibration environments.

Sea Voyage Training and Motion Sickness Effects on Working Ability and Life Quality After Landing

BACKGROUND: The effects of seasickness on working performance during motion exposure have been reported, while the aftereffects on working ability and life quality decline (WLD) still remain unclarified.METHODS: Two cohorts of healthy male Chinese subjects received either a single (SSV) or repeated (RSV) sea voyage training program on different vessels. A seasickness incidence (SSI) questionnaire was administered to assess the prevalence of seasickness symptoms (vomiting, nausea, other, or no symptoms). A WLD questionnaire was used to survey the general feeling of WLD (severe, moderate, slight, and none) by a 4-point score as well as the incidence rate (IR) of specific WLD items within 24 h after landing.RESULTS: The RSV cohort had lower overall IR of WLD than the SSV cohort (54.64% vs. 63.78%, N 657 for both cohorts). The landing ship trainees in both cohorts showed higher general WLD score and higher IRs of physical fatigue, sleep disorder, and spontaneous locomotion decrement than those trained on the small vessels. Subjects with vomiting or nausea had higher general WLD score and higher IRs of concentration distraction, physical fatigue, anorexia, and spontaneous locomotion decrement than those with no symptoms. Higher IRs of firing accuracy decline (SSV: 21.35% vs. 7.13%, 9.14%; RSV: 22.11% vs. 9.28%, 5.27%), equipment operation disturbance (SSV: 16.85% vs. 3.57%, 6.85%; RSV: 20.47% vs. 7.85%, 7.03%) were also observed in the vomiting subjects than those with other symptoms and no symptoms.DISCUSSION: Significant WLD after landing was associated with transportation types, seasickness severity, and habituation during sea voyage training.Qi R-R, Xiao S-F, Su Y, Mao Y-Q, Pan L-L, Li C-H, Lu Y-L, Wang J-Q, Cai Y-L. Sea voyage training and motion sickness effects on working ability and life quality after landing. Aerosp Med Hum Perform. 2021; 92(2):9298.

Review of the evidence for oceans and human health relationships in Europe: A systematic map

BACKGROUND

Globally, there is increasing scientific evidence of critical links between the oceans and human health, with research into issues such as pollution, harmful algal blooms and nutritional contributions. However, Oceans and Human Health (OHH) remains an emerging discipline. As such these links are poorly recognized in policy efforts such as the Sustainable Development Goals, with OHH not included in either marine (SDG14) or health (SDG3) goals. This is arguably short-sighted given recent development strategies such as the EU Blue Growth Agenda.

OBJECTIVES

In this systematic map we aim to build on recent efforts to enhance OHH in Europe by setting a baseline of existing evidence, asking: What links have been researched between marine environments and the positive and negative impacts to human health and wellbeing?

METHODS

We searched eight bibliographic databases and queried 57 organizations identified through stakeholder consultation. Results include primary research and systematic reviews which were screened double blind against pre-defined inclusion criteria as per a published protocol. Studies were limited to Europe, US, Australia, New Zealand and Canada. Data was extracted according to a stakeholder-defined code book. A narrative synthesis explores the current evidence for relationships between marine exposures and human health outcomes, trends in knowledge gaps and change over time in the OHH research landscape. The resulting database is available on the website of the Seas, Oceans and Public Health in Europe website (https://sophie2020.eu/).

RESULTS

A total of 1,542 unique articles were included in the database, including those examined within 56 systematic reviews. Research was dominated by a US focus representing 50.1% of articles. A high number of articles were found to link: marine biotechnology and cardiovascular or immune conditions, consumption of seafood and cardiovascular health, chemical pollution and neurological conditions, microbial pollution and gastrointestinal or respiratory health, and oil industry occupations with mental health. A lack of evidence relates to direct impacts of plastic pollution and work within a number of industries identified as relevant by stakeholders. Research over time is dominated by marine biotechnology, though this is narrow in focus. Pollution, food and disease/injury research follow similar trajectories. Wellbeing and climate change have emerged more recently as key topics but lag behind other categories in volume of evidence.

CONCLUSIONS

The evidence base for OHH of relevance to European policy is growing but remains patchy and poorly co-ordinated. Considerable scope for future evidence synthesis exists to better inform policy-makers, though reviews need to better incorporate complex exposures. Priorities for future research include: proactive assessments of chemical pollutants, measurable impacts arising from climate change, effects of emerging marine industries, and regional and global assessments for OHH interactions. Understanding of synergistic effects across multiple exposures and outcomes using systems approaches is recommended to guide policies within the Blue Growth Strategy. Co-ordination of research across Europe and dedicated centres of research would be effective first steps.

Human responses to wave slamming vibration on a polar supply and research vessel

A polar supply and research vessel is pre-disposed to wave slamming which has caused complaints among crew and researchers regarding interference with sleep, equipment use and research activities. The present work undertook to survey passenger claims of sleep interference, disturbed motor tasks and equipment damage as a result of wave slamming during normal operations of this vessel. The hypothesis was investigated that whole-body vibration metrics from ISO 2631-1 are potentially suitable for the prediction of human slamming complaints. Full-scale acceleration measurements were performed and wave slamming events were subsequently identified from the human weighted acceleration time histories. A daily diary survey was also conducted to gather the human response. The vibration caused by wave slamming was found to be strongly correlated with sleep disturbances and activity interference. Sleep and equipment use were found to be the most affected parameters by slamming. Daily vibration dose values were determined by accumulating the vibration as a result of slamming over 24 h periods. This metric accounted for increased magnitudes and frequency of slamming incidents and proved to be the best metric to represent human responses to slamming vibration. The greatest percentage of activities affected by slamming related to sleep regardless of daily cumulative VDV magnitude. More than 50% of the recorded responses related to sleep when the daily cumulative VDV ranged between 8.0 m/s^1.75-10.0 m/s^1.75. The peak vertical vibration levels recorded on the vessel reach magnitudes which are associated with sleep disturbance in environments where acoustic noise is present.