As blood is pumped by the heart, it exerts a pressure on the walls of the arteries. This pressure -blood pressure - varies within normal limits. During activity it tends to be higher; during sleep, lower. It also shows a tendency to be slightly higher in older people.
The blood pressure is temporarily raised when a person is exposed to anxiety, fear, or excitement, but it reverts rapidly to normal when the causal factor is removed. It is more permanently raised when the artery walls are hardened or otherwise unhealthy, in kidney disease, and in long-standing overweight. In respect of the latter, an improvement in blood pressure can often be achieved by a reduction in weight.
The onset of high blood pressure is usually slow. The early symptoms may include headaches, tiredness, vague ill health, and lassitude. However, high blood pressure is more often found in people who have no symptoms, and a sure diagnosis is only possible with a sphygmomanometer. A patient with suspected high blood pressure should be referred for a medical opinion at the next port.
If the degree of hypertension grows more severe, then the symptoms of headache, tiredness, and irritation become more common and there may be nose-bleeding, visual disturbances, and anginal pain. Occasionally, however, the first sign of hypertension is the onset of complications such as stroke, breathlessness (through fluid retention in the lungs), heart failure or kidney failure. You should check for the latter by looking for oedema and testing the urine forprotein.
Treatment
Temporary hypertension, due to anxiety, should be treated by reducing any existing emotional or stress problems. Anyone thought to be suffering from severe hypertension, or who gives a history of previous similar trouble, should be kept at rest, put on a diet without added salt, and given diazepam, 5 mg three times daily, until he can be referred for a medical opinion ashore.
Persons suffering from a degree of hypertension requiring continuous medication are not suitable for service at sea.
I. Read and translate the text
II. Tell why hypertension may be dangerous