DEAR DR. DONOHUE: I find myself falling sound asleep at my desk, and what is worse, during business meetings. I get enough sleep, and I drink coffee nonstop to keep me awake. I think this is more than usual drowsiness. A co-worker suggested narcolepsy. Can you provide some information? I am only 27, and I am going to lose my job if this doesn’t stop. – R.R.

ANSWER: Narcolepsy is much more than the common daytime sleepiness that so many people complain of. It’s an irresistible sleep attack that arises at inappropriate times and in inappropriate places. It comes about from a derangement of brain chemicals that regulate sleep-wake cycles. It can be disabling, and it can be dangerous. Dropping off while driving is a danger to the driver and to those on the road with him or her.

Three other signs often accompany sleep attacks and are valuable in arriving at the diagnosis. They are:

1. Cataplexy – muscle weakness triggered by laughter, anger or some other strong emotion. The weakness can be so profound that the person slumps to the floor but doesn’t lose consciousness.

2. Sleep paralysis – an inability to move for one or two minutes upon awakening. The person is alert and is quite frightened by the fact the body won’t obey the command to get moving.

3. Hallucinations – vivid and frequently frightening apparitions that appear just before falling asleep or just before wakening.

It’s not necessary that all four signs be present to arrive at the diagnosis, but the more signs one has, the greater is the certainty of diagnosis.

You have me convinced that you are a good candidate for having narcolepsy. It usually begins at young ages. You need to find a doctor conversant in this condition. Your family doctor can give you a name.

There are medicines that help shake the sleepiness of narcolepsy. Provigil is one example.

While you’re waiting for an appointment, see if you can’t arrange to take 20-minute naps during the day. If you have an understanding boss, this shouldn’t be a great issue. Taking that long of a nap can refresh you for one to three hours.

DEAR DR. DONOHUE: I had a case of hiccups that lasted for five hours. I tried a number of suggestions that were given to me, unsolicited, by all who saw my predicament. None worked. Can you give me any idea of what might work if this happens again? – J.G.

ANSWER: Hiccups come from contractions of the diaphragm, the sheet of horizontal muscle that divides the chest cavity from the abdominal cavity. It’s the principal breathing muscles.

Short-lasting hiccups (five hours rates as short-lasting, although I’m sure you would argue the point) are usually due to distention of the stomach from eating too fast, swallowing air, gulping food, drinking carbonated beverages, smoking or drinking alcohol.

I can repeat some home remedies for you, but I’ll bet you tried them. Deliberately holding the breath sometimes breaks a hiccup attack. Swallowing a teaspoon of sugar can sometimes put an end to them. The roughness of sugar is supposed to trigger a reflex that stops diaphragm spasms. Breathing into a paper bag, massaging the ear lobe between the index finger and thumb and sucking a lemon wedge soaked in angostura bitters are other methods relayed to me by readers through the years.

Hiccups that persist – and “persist” can mean weeks or months – might have more serious causes – tumors, abdominal abscesses or gallbladder disease. If finding and eliminating the cause is impossible, medicines like chlorpromazine are prescribed. If they don’t get the job done, then blocking the phrenic nerve – the nerve that serves the diaphragm – can put an end to them.

DEAR DR. DONOHUE: What’s the difference between an embryo and a fetus? – C.M.

ANSWER: Time. In humans, development from the fourth day after fertilization to the end of the eighth week is considered the embryo stage of life.

DEAR DR. DONOHUE: Please tell me how to figure my body mass index. My doctor didn’t say. I am 61 and a female. My BMI is 28. How does one come up with that number? – D.K.

ANSWER: Body mass index – BMI – provides a better picture of the body’s composition than does a weight reading from a scale. A scale can’t tell how much muscle, bone and fat contribute to body weight. If most of your weight is muscle and bone, that’s a good thing. If most of your weight is fat, that’s a bad thing. Body mass index gives a rough approximation of your body’s makeup.

First, convert your height to inches. Then step 1 is to multiply that number by itself. Step 2 is to take that number and divide it into your weight in pounds. Step 3 is to multiply the result by 703. Let’s say you are 5 feet 5 inches tall and weigh 170 pounds. Five feet 5 inches is 65 inches. Step one is to multiply 65 by 65. The result is 4,225. Step 2 is to divide your weight (170) by 4,225. That number is: 0.04. Step 3 is to multiply 0.04 by 703. The answer is 28, your body mass index. Canadians, conversant with metrics, can obtain the BMI by dividing their weight in kilograms by their height in meters squared.

A normal body mass index is 18.5 to 24.9. Overweight is a BMI of 25 to 29.9. Obesity is 30 to 39.9. Extreme obesity is 40 and higher.

Another way to assess your body’s correct fat content is to measure your waist. A man’s waist should not be more than 40 inches (101 cm) and a woman’s, 35 inches (89 cm). Or you can divide your waist measurement by your hip measurement (taken at their largest point). A healthy number for men is less than 0.9, and for women is less than 0.85.

To obtain a true assessment of body fat, sophisticated tests – not available to most people – are needed. However, another reader, J.D., informs me that there is a home scale that provides that information with a harmless electric current. His is a Tonita Model BC-553 Innerscan Body Composition Monitor that sells for $120. Most of us don’t need such accurate information.