(Oct 13) THE maxim - eat, drink and be merry - sounds innocent enough, but it may not be so harmless after all. Indeed, doctors warn that the next big meal could kill you, literally.

'Eating an unusually heavy meal, especially at night, may cause a spike in blood pressure the next morning, which could, in turn, increase the risk of a heart attack,' cautions Dr Goh Ping Ping, a senior consultant and cardiologist at Changi General Hospital.

The warning is timely, given the popularity of eat-all-you-can buffets here and the coming festive celebrations.

'Personally, I don't recommend buffets at all! I'm against it because people tend to over-eat when there's a free flow of food at the table,' laments Dr Goh, who is also the medical director at the Singapore Heart Foundation.

According to her, the stakes are even higher for those in the habit of pairing their free-flow meals with an equally liberal amount of drinks.

'Alcoholic drinks and drinks containing caffeine give added stimulation, which tend to affect a person's blood pressure. In fact, you should not have more than two drinks in a single day,' Dr Goh explains.

She warns that this is especially so for women, who have lower metabolic rates compared with men. As such, women should limit themselves to just one drink a day.

Blood pressure gives an indication of how hard the heart has to work. It is the force exerted on the walls of the body's arteries and the organs as the heart pumps the blood through them.

There are several ways a heavy meal can adversely affect blood pressure, and by extension, the heart. Eating and digesting food releases many hormones into the bloodstream, which can raise the heart rate and blood pressure. The temporary rise in blood pressure increases the oxygen requirements and creates an extra burden on the heart.

High blood pressure may also rupture cholesterol plaques in the arterial wall, triggering the formation of clots that can block a blood vessel, hence leading to a heart attack or stroke.

For a normal, healthy individual, a temporary spike in blood pressure would cause little immediate harm, but for people in the 'high risk' group - including those who suffer from diabetes, high cholesterol or high blood pressure - the surge may just be the spark that lights the fire. As there is often no outward symptom, hypertension is sometimes referred to with dread as a silent killer.

Indeed, most sufferers stay happily unaware of their condition for several years. Many realise the adverse effects only after they have been diagnosed.

'Blood pressure builds over time, and it is a chronic condition. Once you're diagnosed with high blood pressure, you probably have to be on medication for life to keep it under control. That's why diet and prevention become so very important,' says Dr Goh, who advocates the 3-5-7 rule in eating.

'You should have three daily highs, in fresh fruit, fibre and plant-based proteins; five daily lows in fat, cholesterol, salt, sugar and alcohol; and eat till you're seven-parts full,' she explains.

The magic numbers are 140/90. Any reading that surpasses these numbers should set alarm bells ringing.

'Blood pressure is represented by a pair of numbers in terms of millimetres of mercury, mmHg. Normal blood pressure has both a day and night variation, depending on how active or sedate you are, but the difference in pressure should not be more than five to 10mm,' explains Dr Goh.

According to her, blood pressure readings taken at home are usually more accurate than the ones taken at the doctor's office.

'There is a tendency for the patient to be anxious when he visits the doctor, so in general, home readings do tend to be 5-10mm lower,' she says.

Such home readings should ideally be taken before meals, and when one is in a relaxed position. Good posture, too, helps the reading stay accurate.

'Usually, you should take an average of two to three readings, and these should be taken about five minutes apart. The person should sit rather than lie down in bed. Also, the back should be well supported because slouching or crossing the legs can affect blood pressure readings,' advises Dr Goh.

Electronic makers such as Omron and Citizen now offer low-cost monitors that measure blood pressure automatically, which makes it very easy for home readings. Prices for such devices vary depending on brand and model, but usually are between $100 and $300 a set.