Unrelenting insomnia has become a part of my life. My colleagues joke about my 3 a.m. emails. There are weeks when I'd give just about anything for a good night's sleep. I also know I'm not alone. Seventy million Americans suffer from insomnia and it's more common among women. I could take one of the many sleep medications I see advertised, but I'd rather not. Their long-term use can lead to headaches and dependency. So I channeled my late-night energy into researching the science behind some of the common advice.

We've all heard that drinking warm milk before bedtime can induce sleepiness. The theory is that when tryptophan, an amino acid in milk, is released into the brain, it produces serotonin - a serenity-boosting neurotransmitter. But, according to Dr. Art Spielman, an insomnia expert at the City University of New York, tryptophan-containing foods like milk don't produce the same hypnotic effects pure tryptophan does. So warm milk at bedtime may be comforting, but it won't boost sleep-promoting serotonin.

Many tea blends like chamomile, lemon balm and passionflower are touted for their sleep-promoting properties. Unfortunately their effectiveness hasn't been proven in clinical studies according to the American Academy of Sleep Medicine. Dr. Spielman speculated that a warm liquid before bedtime may promote sleepiness for some people by generating body heat. Beware though: drinking liquids close to bedtime can mean nighttime trips to the bathroom. A cup of "sleepy-time" tea might be worth a try if you have a strong bladder.

Having a nightcap is enticing. But though a glass of wine may help you fall asleep, excessive alcohol use can make you wake up during the night. One theory is that alcohol suppresses the Rapid Eye Movement sleep state that's critical to a good night's sleep. Dr. Spielman told me that one of his patients became remarkable better when he reduced his alcohol intake from 20 to three drinks per week. So drink moderately, if at all, and avoid drinking within a few hours of bedtime.

What about caffeine? It affects everyone differently, so if you're sensitive it might be worth trying to cut down or limit caffeine to the morning only. This can mean more than just cutting out a cup of coffee, the number one source of caffeine in Americans' diets. Soft drinks, tea and chocolate also contain caffeine.
Our ability to excrete caffeine decreases with age so while you might have tolerated four cups of coffee a day when you were 20, you'll probably need to cut down as you get older. So cut down on caffeine or limit it to the morning and if your insomnia persists, consider going cold turkey.

I'm going to try many of these in my unrelenting quest for some shuteye. As for my colleagues, they'll just be content if my middle-of-the-night e-mails taper off.