ENG1 BMI assessment considers both body mass index and physical capability. Where BMI is greater than 35, the MCA requires a valid Chester Step Test completed within the preceding 3 months, alongside assessment of associated medical risks and physical capability.
Written and medically reviewed by Dr Farah MacDonald | MCA Approved Doctor & Occupational Health Physician | Updated September 2026
The current statutory framework is MSN 1886 (M+F) Amendment 3, published by the Maritime and Coastguard Agency in October 2025.
BMI is only one part of the ENG1 assessment. The key question is whether the seafarer can perform their normal and emergency duties safely and whether obesity is associated with other medical risks.
No. There is no single BMI figure above which an ENG1 certificate must automatically be refused.
BMI is used by the MCA as an indicator that further assessment may be required.
As BMI increases, there may be a greater likelihood of associated conditions such as high blood pressure, diabetes, obstructive sleep apnoea, cardiovascular disease or musculoskeletal limitations.
The Approved Doctor must therefore consider both the individual’s medical risk and whether they have sufficient physical capability to undertake routine and emergency duties safely.
MCA guidance identifies BMI over 35 as a level at which closer assessment of physical capability and associated medical risk is required.
This does not mean that a seafarer with a BMI over 35 is automatically unfit.
The Approved Doctor considers:
The purpose is to establish whether the seafarer can perform safely at sea rather than simply to assess body weight in isolation.
Seafarers may need to climb stairs or ladders, move around a vessel in difficult conditions, wear protective equipment and respond quickly during emergencies.
Physical capability assessment therefore considers whether the seafarer has adequate:
Where additional objective assessment is needed, the MCA guidance recognises exercise testing, including step tests, as a useful way of assessing cardio-respiratory fitness.
Where a seafarer’s BMI is greater than 35, the MCA requires a valid Chester Step Test as part of the ENG1 fitness assessment.
The test must have been completed within the 3 months preceding the ENG1 examination. This requirement applies to all seafarers with BMI over 35; there is no exemption based on occupation, previous fitness or apparent physical capability.
The Chester Step Test provides an objective assessment of aerobic fitness and helps the MCA Approved Doctor determine whether the seafarer has sufficient physical capability for routine and emergency duties at sea.
If you do not already have a valid Chester Step Test result, Marina Medicals can complete the test during the same appointment before the ENG1 certification decision is made.
No.
A BMI above 35 does not automatically result in an unfit decision.
Depending on the overall assessment, possible outcomes may include:
The decision is based on the seafarer’s overall medical fitness and ability to perform their duties safely.
The Chester Step Test is a progressive, submaximal exercise test used to assess aerobic fitness.
You repeatedly step on and off a platform in time with a set cadence. The stepping rate increases progressively while your heart rate and perceived exertion are monitored.
The test does not require you to exercise to your absolute maximum capacity. It is stopped when the appropriate physiological or test endpoint is reached.
For ENG1 assessment, the result provides the MCA Approved Doctor with objective information about cardio-respiratory fitness and physical capability.
A Chester Step Test result is interpreted as part of the overall ENG1 assessment rather than in isolation.
Where the result raises concern about cardio-respiratory fitness or physical capability, the Approved Doctor may need to consider the worker’s medical history, examination findings, symptoms and any associated medical conditions before making a certification decision.
Further assessment or improvement in physical fitness may sometimes be required before certification can be completed.
BMI over 35 may be associated with medical conditions that are independently relevant to fitness for sea service.
These can include:
The Approved Doctor therefore considers both physical capability and associated medical risk.
Yes. Depending on the overall medical assessment, an ENG1 certificate may be issued for less than the usual maximum duration where closer medical review is appropriate.
Restrictions may also be applied where the MCA medical standards require limitations on duties, vessel type or area of operation.
Where a certificate is restricted or an applicant is found unfit, the Approved Doctor issues an ENG3, which explains the decision and the right to request an independent medical review.
If your BMI is likely to be over 35:
Do not undertake crash dieting, dehydration or medication changes simply to alter your weight before the assessment.
The statutory ENG1 examination fee is £115.
At Marina Medicals, the Chester Step Test costs £125.
Where both are required:
ENG1 Medical + Chester Step Test = £240
The MCA permits Approved Doctors to charge separately for additional tests such as a step test, provided the additional charge is agreed before testing.
No. BMI over 35 requires additional physical-capability assessment, including a valid Chester Step Test under the current MCA instruction, but it does not automatically mean that an ENG1 cannot be issued.
The current requirement applies where BMI is greater than 35. The Approved Doctor will calculate your BMI during the medical and determine whether the additional requirement applies.
For BMI greater than 35, the Chester Step Test must have been completed within the 3 months preceding the ENG1 medical.
Yes. Marina Medicals can complete the Chester Step Test and ENG1 medical during the same visit where required.
There is no single body-weight cut-off that automatically determines ENG1 fitness. BMI, associated medical risk and physical capability are assessed together.
An ENG1 may normally be valid for up to 2 years, although a shorter certificate may be issued where clinically appropriate.
References:
Marina Medicals provides MCA ENG1 medicals and Chester Step Tests in Cardiff.
For ENG1 BMI over 35 assessments, Marina Medicals can complete the required Chester Step Test during the same visit.
