Melatonin for Jet-Lag

Jet-lag is a condition caused by desynchronization of the biological clock. It is usually caused by drastically changing your sleep-wake cycle, as when crossing several time zones during east-west travel, or when performing shift work. Jet-lag is characterized by fatigue, early awakening or insomnia, headache, fuzzy thinking, irritability, constipation, and reduced immunity. The symptoms are generally worse when flying in an easterly direction, and it may take as long as one day for each time zone crossed in order to fully recover. Older people have an even tougher time adjusting to these changes than younger people.

Circadian disturbances can easily result from conditions other than jet travel. We call these “artificial jet-lag syndromes” because jet-lag is universally understood. Artificial jet-lag can be induced by working night shifts, working rotating shifts (like physician-interns, management trainees for 24-hour businesses, and soldiers under battle-alert conditions), or by staying up all night. Whatever its causes, jet-lag and artificial jet-lag syndromes are seriously debilitating to cognitive function.

Melatonin taken in the evening (in the new time zone!) will rapidly reset your biological clock and almost totally alleviate (or prevent) the symptoms of jet-lag. The ability of melatonin to alleviate jet-lag was demonstrated in a study of 17 subjects flying from San Francisco to London (eight time zones away). Eight subjects took 5 mg of melatonin, while nine subjects took a placebo. Those who took melatonin had almost no symptoms of jet-lag (see illustration below) [Arendt, et al., 1986]. Six out of nine placebo subjects scored above 50 on the jet lag scale, and all of the melatonin subjects scored below 17.

Most people sleep well with melatonin, and wake up the next day refreshed with no symptoms of jet-lag [Claustrat, 1992] (although they may still have some fatigue from the wear and tear of traveling).

Many melatonin fans without any noticeable symptoms of circadian disturbance are now using melatonin to enhance their circadian rhythms. They report that it helps them get to sleep and helps them sleep more soundly. It also makes them more alert the next day and even lessens mid-afternoon tiredness (and naps).

In all cases, melatonin should be taken at night (preferably before midnight) before going to bed. That’s when your pineal gland naturally releases melatonin. Taking melatonin at night (or before your normal bedtime if you are a shift worker) helps restore and maintain normal circadian metabolic rhythms. See the Precautions section in this chapter.

Does Melatonin Improve or Impair Mental Performance?

We were initially surprised to find a number of studies which reported on adverse effects of melatonin on performance and alertness. One study [Lieberman, 1984] reported that melatonin users were less alert, more sleepy, and demonstrated slowed “choice-reaction time.” Other studies also indicated that melatonin impaired memory and performance [Neville, 1986]. We found, however, that in all of these studies, melatonin was given to subjects in the daytime, before the performance tests, just the opposite of what they should have been doing!

With circadian enhancers like melatonin, the timing is critical. When taken in opposition to the body’s natural circadian rhythm, they cause cognitive deficit just like jet-lag does. But when taken in synchronization with the body’s natural circadian rhythms, they enhance mental performance. By giving melatonin in the daytime, before the cognitive tests, the researchers were causing the test subjects to suffer from artificial jet-lag and then measuring the resulting cognitive impairment. Disruption of circadian rhythms produces amnesia by interfering with the circadian organization of memory processes [Sandyk, 1991].

Melatonin, by correcting circadian rhythms should, theoretically, improve mental performance. We could only find one study in which melatonin was given to rats at night. This study confirmed that next-day measures of learning ability improved [Ovanesov, 1990]. We believe that melatonin, when taken before sleep, will decrease sleep disturbances of any kind, and will, therefore, improve mental function during the following day.

Melatonin for SAD and Depression

Two particularly notable features of depression and SAD are diminished nighttime release of melatonin and abnormal sensitivity to melatonin suppression by light [Brown, 1989]. This has led researchers and clinicians to try melatonin as an experimental treatment for depression, with gratifying results.

Melatonin Extends Lifespan

Melatonin has also been shown to improve immunity and extend lifespan in rodents [Regelson & Pierpaoli, 1987; Pierpaoli, et al., 1990]. Dr. Maestroni [1988] gave melatonin to middle-aged mice each evening. The treated mice became more healthy (better posture, increased activity levels, and thicker, more lustrous fur) and lived an average of 20% longer than control mice.

Melatonin secretion naturally drops off with age (see the following graph). This decrease is so reliable that blood melatonin levels have been proposed as a measurement of biological age [Nair, et al., 1986]. This age-related reduction in melatonin levels may partially account for the reason many older people have difficulty sleeping at night, and for why they are so fatigued during the day. We believe they may be suffering from age-induced “jet-lag.” Restoration of normal sleep-wake cycles in many  elderly patients with supplemental melatonin before bedtime has dramatically improved their quality of life.

Melatonin: Anti-Stress Hormone

Nighttime administration of melatonin can also counteract the immune-suppressing effects of acute anxiety stress in mice. Measures used to confirm this were: thymus weight, antibody production, and ability to fight off a lethal viral infection [Pierpaoli and Maestroni, 1987].

Melatonin for Cancer Treatment

Melatonin also appears to inhibit tumor growth. In the United Kingdom, a study was carried out on 14 cancer patients with cancers of different types. The researchers concluded that “this study would suggest that melatonin may be of value in untreatable metastatic cancer patients, particularly in improving their quality of life. Moreover, based on its effects on the immune system, melatonin could be tested in association with other anti-tumor treatments” [Lissoni, 1989].

Melatonin in Alzheimer’s Disease

Very recent studies have found reduced levels of melatonin in the cerebrospinal fluid of patients with Alzheimer’s disease compared to age-matched control subjects [Tohgi, 1992; Skene, 1990]. Since circadian rhythms are disrupted in Alzheimer’s disease, it is interesting to speculate whether restoration of melatonin to normal levels in these patients would alleviate other symptoms as well.

Melatonin and Exposure to Electromagnetic Fields

Sunlight is the primary environmental influence that regulates the internal clock and the associated late-night melatonin pulse. There is some evidence that the earth’s magnetic field may also be an environmental signal affecting circadian rhythms in humans. When shielded from the earth’s ambient magnetic field, human circadian rhythms can become disrupted [Tohgi, 1992].

Exposure to electromagnetic fields from appliances and from powerlines may be even more significant than we think. There are reports of altered neural function from exposure to ELF (extremely low frequency) fields, as found near high-voltage powerlines, including suppressed melatonin levels [Lovely, 1988]. Supplemental melatonin may help to overcome the negative health consequences of these fields.