Saliva cortisol level as a strain parameter for crews aboard merchant ships

Area of Science:

• Occupational Health
• Endocrinology
• Maritime Studies

Background:

• Seafarers face numerous psychosocial stressors in maritime environments.
• Saliva cortisol testing is a validated method for assessing individual physiological strain.
• Understanding seafarer stress is crucial for occupational health and safety.

Purpose of the Study:

• To evaluate crew strain on container ships using saliva cortisol levels.
• To analyze cortisol variations based on occupational groups and voyage phases (port, river, sea).
• To identify correlations between cortisol levels and specific shipboard stressors.

Main Methods:

• Collection of over 4,000 saliva samples from 304 seafarers across 22 voyages.
• Analysis of cortisol concentrations considering occupational groups (nautical officers, deck ratings, engine personnel) and voyage episodes.
• Statistical evaluation of cortisol levels in relation to working hours, shipboard stressors, and demographic factors.

Main Results:

• Seafarer cortisol levels were generally lower than a healthy reference population.
• Significant differences in cortisol levels were observed between occupational groups (decreasing from officers to ratings).
• Cortisol levels were highest during port stays, followed by sea and river passages.
• Increased working hours and terminal visits were associated with higher cortisol levels.
• No association was found between cortisol and age, smoking, duration of stay, or subjective stressors like noise and vibration.

Conclusions:

• Saliva cortisol levels effectively reflect the strain experienced by seafarers.
• Occupational group and ship's voyage episode are significant factors influencing cortisol levels.
• Acute shipboard stressors, particularly working time and workload, are linked to elevated cortisol.
• Methodology involving on-site sample collection by trained personnel ensures reliable data for maritime stress research.