Crew Health Advice: Hypertension

Hypertension remains one of the most common and consequential non-communicable diseases detected in pre-employment medical examinations (PEMEs). It is a leading cause of medical unfitness decisions in the maritime industry, contributing significantly to both individual health risk and operational safety.

Global Prevalence & Burden

• An estimated 1.4 billion adults aged 30–79 years worldwide currently live with hypertension (blood pressure ≥140/90 mmHg). This reflects a substantial rise from past decades and underscores a continuing global trend.
• Only about one in five (≈23–28 %) of those with hypertension have it effectively controlled.
• Two-thirds of people with hypertension live in low- and middle-income countries, including many African and Asian nations relevant to maritime crews.
• A large proportion of individuals with hypertension remain undiagnosed (≈44 %).

Health Impact

Hypertension is a major risk factor for:

• Heart disease and heart failure
• Stroke
• Chronic kidney disease
• Vascular dementia and other cognitive impairments
  The condition accelerates vascular damage silently over years, with many patients reporting no symptoms until serious complications arise.

The economic toll of hypertension extends to healthcare delivery systems and society, with millions of annual deaths and large cumulative costs borne by health services worldwide — for example, projections suggest that cardiovascular diseases cost low- and middle-income countries trillions of US dollars between 2011 and 2025.

Updated Description of Hypertension

Hypertension is defined as a sustained elevation of blood pressure with a systolic reading ≥140 mmHg and/or diastolic reading ≥90 mmHg on repeated measurements. It may remain asymptomatic for years, making routine screening essential, particularly in occupational and maritime settings.

As blood pressure remains uncontrolled over time, high pressure injures vessel walls, promoting atherosclerosis and compromising blood flow to the heart, brain, and kidneys.

Risk Factors

Hypertension results from multiple interacting modifiable and non-modifiable risk factors:

Non-modifiable

• Age: risk increases with older age
• Genetics / Family history

Modifiable

• Overweight and obesity
• Physical inactivity
• Unhealthy diet (high salt, high sugars, low fruit/vegetable intake)
• Excess alcohol consumption
• Tobacco use
• Chronic stress
• Poor sleep quality and insufficient sleep:
   Recent evidence shows that short sleep duration (<7 hours) and poor sleep quality significantly increase the risk of developing hypertension.1 People sleeping less than 6–7 hours per night face an elevated risk compared to those with adequate sleep, and poor sleep patterns independently raise hypertension risk regardless of genetic predisposition.

In occupational settings such as shipping crews, irregular sleep schedules, shift work, and disrupted circadian rhythms can compound these sleep-related risks and should be considered alongside traditional lifestyle factors.

Measures for Improvement & Prevention

Lifestyle Interventions:

Encourage the following strategies, which are practical both ashore and at sea:

1. Healthy Weight & Diet
   • Aim for a BMI < 25 where feasible.
   • Emphasise fresh vegetables, fruits, lean proteins.
   • Reduce salt (sodium) intake — be aware of hidden sources like sauces.
   • Reduce starches and refined sugars.
   • Consider intermittent daily fasting – no food for 16 hours, then to eat 2-3 healthy meals within an 8 hour time window.
2. Regular Physical Activity
   • Target ≥30 minutes of moderate exercise most days.
   • Include strength and flexibility training where possible.
3. Smoking Cessation
   • Complete cessation is ideal; any reduction also benefits cardiovascular health.
4. Alcohol Moderation
   • Follow internationally recognised limits (e.g., no more than ~14 units per week for men and ~ 7 iU per week for women; spread over days when on leave. Alcohol is typically now removed from maritime working environments, especially in safety critical positions).
5. Stress Management
   • Techniques such as controlled breathing, meditation, and structured downtime help reduce nervous system stress.
6. Sleep Quality & Duration
   • Strive for 7–9 hours of restful sleep each night whenever operational schedules permit.
   • Prioritise consistent sleep timing, create a quiet, dark sleep environment, and limit late-night screen exposure.
   • Screen for sleep disorders such as obstructive sleep apnea in personnel with daytime fatigue or high blood pressure to improve outcomes.

Conclusion

Hypertension continues to be a pervasive and preventable health issue with grave consequences if left unchecked. Early detection in PEMEs, robust lifestyle intervention strategies — including sleep optimisation — and appropriate medical treatment can reduce the risk of serious cardiovascular complications and improve fitness for duty.

 

This article was written by Dr. Brauer of Dr Brauer Associates.