Staying Healthy at Sea: The Complete Guide

Your health is the most critical asset in your maritime career — and it's one of the few things entirely within your control. An expired ENG1 ends a contract. Unmanaged cardiovascular risk becomes a cardiac event 400 miles from the nearest hospital. Poor nutrition and chronic sleep disruption compound over years into conditions that ground careers. This guide covers the practical steps to protect your health across a long sea career.

The ENG1 Medical Certificate

The ENG1 is issued by an MCA-approved doctor and confirms fitness for seafarers' duties. It must be current at all times while working at sea.

• Validity: 2 years for seafarers under 70; 1 year for seafarers 70 and over
• What it assesses: Vision (including colour vision for deck officers), hearing, cardiovascular health, musculoskeletal function, mental health, neurological conditions, diabetes, respiratory function
• Cost: £120–£200 at approved doctors
• Book ahead: Popular approved doctors can have wait times of several weeks. Do not let your ENG1 expire between contracts — book the renewal appointment 6–8 weeks before expiry.

Managing conditions that affect ENG1

Common conditions that affect ENG1 approval include hypertension, diabetes, visual impairment, and mental health conditions. A condition does not automatically fail you — many seafarers with managed conditions retain their certificate. What matters is that conditions are actively managed, monitored, and disclosed. An undisclosed condition that leads to an incident at sea creates both medical and legal risk.

Nutrition on Board

Food quality varies enormously between vessels — a well-managed ship with a good cook is a health asset; a vessel serving calorie-dense, processed food three times a day is a health liability. Either way, choices within what's available matter significantly over a long contract.

Practical principles

• Protein at every meal: Preserves muscle mass during physically demanding work and during the sedentary phases of watchkeeping
• Limit refined carbohydrates: The standard ship's mess diet is often very high in white rice, bread, and fried food. Adding vegetables and reducing the carbohydrate portion where possible makes a significant difference over a 3-month contract
• Hydration: Dehydration impairs concentration and mood. In hot climates, requirements increase substantially. Water is always preferable to sugary drinks or excessive coffee
• Alcohol: Moderate consumption is a reality on many vessels. Heavy consumption impairs sleep quality, increases cardiovascular risk, interacts badly with fatigue, and is incompatible with safe watchkeeping

Sleep and Watchkeeping

Watchkeeping disrupts circadian rhythm — there is no way around this. But the degree of disruption varies significantly depending on how you manage the periods between watches.

Maximising sleep quality in disrupted schedules

• Blackout curtains: Essential if you sleep during daylight hours. Request them if they're not provided.
• Temperature: Cool environments improve sleep quality. If your cabin is hot, a fan pointed away from you (for air circulation without direct draft) helps.
• Screens before sleep: Blue light from phones and tablets suppresses melatonin. The 30 minutes before you need to sleep should not involve a screen.
• Consistent timing: Try to sleep at the same time relative to your watch pattern — your body adapts better to a consistent disrupted schedule than to a variable one.
• Short naps: A 20-minute nap (no more) between watch segments restores alertness without creating sleep inertia. Longer mid-watch naps often leave you groggier than before.

Vaccinations

The vaccinations you need depend on your trading area. The core vaccinations recommended for most seafarers:

• Hepatitis A and B (particularly important for routes through West Africa, Southeast Asia)
• Typhoid (for tropical routes)
• Yellow fever (required for entry to some countries — you must carry the International Certificate of Vaccination)
• Tetanus/diphtheria/polio booster (every 10 years)
• Meningitis ACWY (for some trading areas)

Consult a NHS travel medicine clinic or specialist travel vaccination centre when you know your next contract's trading area. Some vaccinations require multiple doses over weeks — plan ahead.

Dental

Dental emergencies at sea are painful, disruptive, and medically complex. The ship's medicine chest contains analgesics and temporary filling materials, but treatment is often impossible until port. A dental check-up before every contract is inexpensive compared to a dental emergency off Suez.

Exercise

Physical activity has direct mental health benefits as well as physical ones. Most vessels have some gym equipment — even a modest selection of free weights and a treadmill. Building regular exercise into every watch rotation, regardless of how tired you feel, consistently improves mood, sleep quality, and resilience under stress.

Aim for 30 minutes of moderate activity (walking, rowing, cycling) on rest days between watches. Resistance training (weights, bodyweight) twice a week maintains muscle mass and bone density on long contracts. Stretching is disproportionately beneficial for engine room crew performing physical maintenance work in confined spaces.