Too many carbohydrates

If you eat lunches that are high in carbohydrates but low in protein, you may find yourself feeling tired in the afternoon. That's because carbohydrates increase the brain's production of calming chemical serotonin. Research suggests that protein, by limiting serotonin production, can boost carbohydrate-induced sleepiness. You may not need to decrease overall carbohydrates or increase your protein consumption (carbs should make up the bulk of a healthy diet, and most of us consume plenty of protein). Instead, try to make sure your meals contain a balance of carbohydrates and protein. This should help you avoid those mid-afternoon slumps.

Snooze - till-noon weekends

Some clever work drone may have once said, "I'll catch up on all of my sleep the first year I'm dead." But most of us opt for Saturday mornings. Bad move, for we each have a biological clock that determines when we are sleepy and when we are alert. When you wake up every morning at seven but sleep until noon on weekends, you can upset your biological clock and end up feeling even more fatigued.

It partly has to do with the body's release of cortisol, a hormone associated with alertness, which begins for seven-o'clock risers between three and four in the morning and peaks at about eleven. When you lie in bed past this time, you suppress the level of cortisol. This can dump your brain into that weekend twilight zone.

Catch up on weekends by going to bed early, not sleeping late. To keep your biological clock happy, it is best to wake up every morning at about the same time.

Blood-pressure quirks

Intermittent bouts of low blood pressure, known as neurally mediated hypotension (NMH)may cause exhaustion. When researchers at John Hopkins Hospital in Baltimore examined 23 people with chronic fatigue syndrome, 22 turned out to have NMH. Once they were treated for the condition, nine reported full recovery from fatigue and seven others noted some improvement.

If you become woozy after standing for long periods, dizzy while taking a hot shower, or if you're prone to fainting have a physician evaluate you for NMH. The test is simple: The doctor puts you on a table and tilts it so your head is resting 70 degrees above your feet. This simulates long periods of standing. If you faint, or if your blood pressure falls and you experience lightheadedness or nausea after several minutes, you probably have the condition. Treatment involves regulating the blood pressure, often by simply adding salt and fluids to the diet, and possibly a medication to prompt the kidneys to retain more sodium.

Dehydration

Once you feel thirsty, you've already begun to lose a significant amount of fluid, according to sports nutritionist Kristine Clare. As your fluid level decreases, you'll start to notice a decline in physical performance. It makes sense. A lack of water can cause a decrease in blood volume, and that can bring on fatigue. Drink eight to ten glasses of water a day, or more if you exercise heavily.

Drug side effects

Sure, you know that certain antihistamines, cold medications and cough syrups can make you drowsy. But you may not have known that the list of potential energy sappers features many other familiar drugs that can cause drowsiness in some people. These include certain blood-pressure medications and even some diuretics. If you feel tired or run-down, ask your doctor or pharmacist whether the medication you're taking might be the cause, and what alternatives may be available.

Stress

The pressure of a deadline can leave you wiped out for the afternoon. Fear makes you tense your muscles, which leads to fatigue, just as if you were out chopping wood. Fear can also make you hold your breath, depriving you of oxygen. This, too, can lead to fatigue.

Next time you're in the hot seat, close your eyes and envision yourself in a tranquil setting. Concentrate on breathing deeply and slowly. Whenever possible, you schedule some discomforting event in the morning so you don't spend the other day worrying about it.

Eyestrain

If you're having a hard time focusing, you're probably twisting your body into awkward positions, leaning forward into the computer screen or hunching over your desk. Vision problems also hamper concentration, which can cause fatigue.

Have your vision checked, and take a five-minute break from your computer or paper work every hour. Use the time to do other tasks, such as making phone calls.

Somber colors

Surrounding yourself with nothing but somber colors can make you both fatigued and depressed. Add warm colors to your environment such as yellow, orange and especially red. These are the colors of fire. After eons of association, we are programmed to respond to them. If you want a quick cure for fatigue, focus on something red. A few items placed nearby should do the trick. But don't overdo it. Your environment can become too stimulating, and that, too, can be exhausting.

(Selected from Men's Health, March 1997, written by Russell Wild)