Hyperlipidaemia predisposes to premature coronary and cerebrovascular disease which can cause sudden incapacity. If such incapacity occurred in a diver underwater it would prove hazardous to both the diver and his companion.

Individuals with hyperlipidaemia will therefore only be permitted to dive if they have no symptoms or signs suggestive of vascular occlusive complications and are able satisfactorily, to complete a treadmill exercise test without evidence of myocardial ischaemia. Individuals with hyperlipidaemia may be subject to more frequent medical assessments including exercise testing depending on their degree of hyperlipidaemia, its cause and its assessed prognosis. Often repeat medical assessment annually will be appropriate.