The Long Watch: What Fatigue Steals

Everyone is talking about seafarer fatigue these days. But what is it really about? From Laura Benzonana, PhD and Stefan Fröbe: a clear, no-nonsense look beneath the surface, with evidence from academic studies.

Most of us think of fatigue as being tired after a long shift, a rough port call, or a sleepless night on watch. In reality, fatigue runs much deeper. It’s not simply about feeling sleepy. It’s about what happens to your body and mind when rest is constantly disrupted. When stress never lets up. And when the “normal” routines of life ashore don’t apply at sea.

Seafarers are unique. Workplace and home are the same place for months. Fatigue has many causes: long working hours, solitude, irregular watch schedules, night shifts, heavy noise and vibration, excessive paperwork, and limited time for quality rest. Now add inspections to the workload. Also, add patchy connectivity with family. These are not occasional issues. This is life at sea.

Fatigue is more than being tired. It’s a state of exhaustion that wears down health and attitude to safety. Over time, it doesn’t just slow reactions on the bridge or in the engine room. It compromises situational awareness and raises the risk of long-term illness.

Part I: Under Pressure – Your Heart

Fatigue clouds the head and keeps stress high. Blood pressure rises. The heart takes a steady load. Seafarers carry big risks: about 45% have high blood pressure and more than 40% are overweight (Sagaro et al., 2023). These risks rarely travel alone. The same meta-analysis found that hypertension, excess weight, smoking, and high cholesterol tend to cluster in the same person (Sagaro et al., 2023). If fatigue pushes sleep and diet off course, other risks join in. The impact on the heart grows.

Why does fatigue play such a big role? Because broken sleep and night shifts disturb the body clock. Metabolism slips. The body handles sugar poorly, raising diabetes risk over time (Rogers et al., 2024). Appetite hormones drift: ghrelin (hunger) rises while leptin (satiety) falls, leading to roughly 250 extra calories per day on average (Chaput et al., 2023). At sea, that often means more snacks and heavier meals.

In short: Fatigue → broken sleep → more eating and sugar problems → weight gain → higher blood pressure → heart at risk.

The role of noise

Noise is a constant companion: engine throb, machinery hum, cargo ops. Over time, it damages hearing and fuels fatigue. Engine-room noise often exceeds safe limits, and many seafarers don’t use hearing protection consistently (Kim et al., 2024). This isn’t only about ears. Hearing loss has been linked with heart disease, high blood pressure, and stroke (Fuquay Law Firm, 2024). Noise stresses the body, disturbs sleep, and deepens fatigue. When hearing loss develops, the effort to catch alarms, radio calls, and even simple conversations adds more strain.

The cycle feeds itself. Fatigue makes ear protection less likely. Constant noise blocks proper rest. Body and hearing both take a beating.

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Next up on November 18: Part II — The Hidden Toll on Mental Health. Follow to get it in your feed.

References

1.       Chaput, J-P., McHill, A.W., Cox, R.C., et al. (2023). The role of insufficient sleep and body clock disruption in obesity. Nature Reviews Endocrinology, 19, 82–97.

2.       Fuquay Law Firm. (2024). Excessive Noise and Vibration: A Maritime Hazard.

3.       Jonglertmontree, W., et al. (2022). Mental health problems and their related factors among seafarers: a scoping review. BMC Public Health, 22, 282.

4.       Kim, S., et al. (2024). Impact of ship noise on seafarers’ sleep and fatigue. Applied Sciences, 14(7), 662–670.

5.       Rogers, A., Zhang, J., Gadde, K.M. (2024). Sleep, circadian rhythms, and diabetes: mechanisms and future directions. Diabetes/Metabolism Research and Reviews, 40(4), e3667.

6.       Sagaro, G.G., Di Canio, M., Battineni, G., & Amenta, F. (2023). The magnitude of heart disease risks in seafarers: a study combining data from many groups. Journal of Personalized Medicine, 13(5), 861.

7.       Sagaro, G.G., et al. (2024). Self-reported diabetes among seafarers: linked to overweight, obesity, and long working hours. International Maritime Health, 75(1), 19–28.

8.       Svetina, M., et al. (2024). Factors impacting seafarers’ mental health and career intentions: a study of seafarers from 12 countries. INQUIRY.

9.       West of England P&I Club. (2025). The Rising Tide of Fatigue Among Seafarers.