Making Sense of Medicine

Crossing the ocean on a ship gives the body time to the slightly earlier sunrise every day (traveling east) or the slightly later sunrise (traveling west). Airplane travel across several time zones is too speedy for most of us to adjust.

Our bodies can “expand” the day more easily than it can “compress” it. Thus traveling westward, and ending up with more hours of daylight, is easier to adjust to than traveling eastward, and ending up with a shorter day.

Most people who cross more than four time zones will experience jet lag. The pineal body, a gland in the skull but just outside the brain proper, produces the hormone melatonin, which helps to regulate our “sleep/wake cycle”. When the sun sets, the gland pours out melatonin. But the gland has some sort of an internal mechanism as well as just sensing when it is dark. If we compress our day (by traveling east), it takes several days for it to “catch up” and produce the right amount of melatonin by bedtime in the new place.

For every time zone crossed traveling east, it takes one approximately one day to fully adjust. Traveling west takes less time, by about a third.

There are ways to speed up the process of adjusting, and lessening jet lag. Going west, a traveler should try to stay awake until the regular bedtime at the new destination. Going east, a traveler should be outdoors in the afternoon and early evening, so the body clock senses the dimming light.

For both east and west travel, it’s best to eat meals at your normal mealtime, according to the clock at your current destination. Also, it’s best to get plenty of exercise – take a long walk and take in the new sights.

Taking melatonin can be helpful. A Cochrane review article in 2002 looked at ten placebo-controlled papers, studying almost a thousand people who took melatonin for jet lag. The bottom line is that taking it significantly helped many of the people. The dose ranged from 0.5mg (which is not commercially available unless you buy the liquid to take that low of a dose) to 5mg. In the U.S. most drugstores carry 3mg melatonin pills without a prescription. Interestingly, the 0.5mg was almost as effective as the 5mg, although the higher dose led to slightly less time before the onset of sleep, and the quality of sleep was also slightly better.

The authors of that review suggested taking melatonin at bedtime for the first four nights at the new destination. For eastward travel (from the U.S. to Europe, say) they also recommend taking a dose on the day of travel, as you are traveling. For that dose, figure out what your regular bedtime will be at the new location and take a dose at that time.

I know it’s hard to remember east versus west, so here’s a memory aid:

If you are in California and your mother is in Rhode Island, she is eating supper while you eat lunch. If you instantly transport yourself to her side, less of your day will be left than if you were still in California. You are asking your body to compress its time clock into a shorter day. That is hard for your body to do. Stretching your day out, going west, is easier on your body.

So here’s what I’ve discovered: Melatonin is a hormone. I’ve known that since medical school, of course, but that fact has struck me as peculiar these past few weeks. Why? Because it’s sold over the counter, and many people take massive amounts of it. No other hormone is available like this. The use of other hormones, such as insulin and thyroid hormone, need careful monitoring. Is melatonin so universally safe that it can be taken at any dose, for however long? The more we learn about melatonin, the less that seems to be the case.

Hormones are substances produced in one place that then go into the bloodstream and have their effect somewhere else. Melatonin is produced in the pineal body, which is just outside the brain proper. Ten times as much of it is made during the night as during the day. Our bodies sense when it is dark and tell the pineal body to make melatonin. If we cross six time zones, however, it takes a few days for the pineal to catch up and produce melatonin at the proper time. Hence comes Jet Lag.

So do people with insomnia benefit from melatonin? Many of them swear by it, but I’m wondering whether they are taking too much. The pills in pharmacies are generally 3mg or 5mg. But the amount that reproduces what our bodies produce at night is equivalent to somewhere between 0.1mg and 0.5mg. Higher doses flood the brain with melatonin, and make it actually less sensitive to its effects. So here is where it is not good to follow the “If a little is good, then more is better” principle. Since a little is all that is needed, stick with a little.

Studies are showing that the ideal amount of melatonin for sleep problems seems to be 0.3mg. But how can you take “0.3mg” when the pill is 3mg? Do you crumble it up and take a tenth, somehow? Not practical. There are liquid preparations available, with one dropperful giving 1.0mg. So you could take a third of a dropperful. If you can’t find it at your pharmacy, check online at www.drugstore.com.

As we age, we gradually produce less melatonin. I wonder if this is why so many older people have trouble sleeping. In the last few weeks, since I’ve been reading about melatonin, I’ve started recommending it to my older patients with insomnia. But I urge them to use the liquid so they only take 0.3mg a night. They may end up needing a little more, but, as with all medications, I much prefer starting at a low dose and creeping up slowly. I’ll follow up in a few months with how people have responded.