Although our understanding of the biochemical and physical processes underlying sleep is still rather crude, we now know enough to be able to modify some of them repeatably.
Sleep is an altered state of consciousness from that of our everyday world. We are put to sleep by increased quantities of serotonin in the brain. Serotonin is an inhibitory neurotransmitter (chemical used for communication between nerve cells) that decreases the firing rate of certain nerve cells. The quantity of serotonin in the brain depends on a day-night clock cycle maintained by the brain. Even in the absence of any external dark or light signal to establish the time of day, most people run on a 23- to 26-hour daily rhythm.
Serotonin is manufactured by the brain from the nutrient tryptophan, which may be obtained from the diet (for example, bananas or milk) or from a nutritional supplement purchased in a drug or health food store. In order for the brain to convert the tryptophan to serotonin, vitamins C and B-6 are required, so supplements of these ought to be taken with tryptophan for best results.
Animal studies have shown that after a large carbohydrate meal more tryptophan enters the brain; insulin released in response to the carbohydrates alters the binding properties of tryptophan to the protein that carries it in the bloodstream. This phenomenon explains, at least in part, why so many people fall asleep at lectures after lunch!
Another aspect of sleep is staying asleep once serotonin has induced us to enter that state. The cholinergic nervous system in the brain uses the neurotransmitter acetylcholine to regulate the input of stimuli from the outside world. When we sleep, this input is greatly reduced, allowing us to stop paying attention to our surroundings and enter the sleep state. Taking choline (along with vitamins B-1 and B-6, which are required for its conversion to acetylcholine by the brain) can help us to stay asleep. Lecithin (which contains phosphatidyl choline) and the prescription drug Deaner® (Riker) are also effective.
Why do we need sleep? This is a question that has interested scientists and nonscientists alike since time immemorial. We still do not know, but there are hypotheses.
An interesting hypothesis is that REM (rapid eye movement) sleep may serve to increase our brain's supplies of certain neurotransmitters, the catecholamines (dopamine, norepinephrine), that are important for learning, memory, long-term planning, emotions, primitive drives, motor activity, and other functions. An increase in these substances has been measured in the brains of experimental animals after REM sleep, and a lack of REM sleep has been known for many years to reduce ability to concentrate and focus and to increase aggressiveness and bad judgment.
REM is associated with dreaming, a fascinating altered state of consciousness. It is initiated in the brain by a release of the hormone vasopressin by the pituitary gland. It is currently available as a prescription drug, Diapid® (Sandoz), used to treat a condition of excess urination caused by a deficit of vasopressin. We have experimented with this drug (because it has been shown to increase intelligence and improve memory in several human clinical trials) and found that it increases the ability to visualize. Thus, its connection with dreaming is not surprising.
Another hypothesis concerning why we sleep is that it removes individuals from the relatively more dangerous night environment to the relative safety of the home territory. It puts us "on hold," so to speak.
One important event that takes place about 90 minutes after we begin to sleep is the release of growth hormone (GH), triggered by serotonin and dopamine. Growth hormone is necessary for the proper function of our immune system—the white blood cells, thymus gland (located behind the breastbone), spleen, bone marrow, and various chemicals, including antibodies, interferon, and complement. The thymus gland enables certain white blood cells, called T-cells, to identify and attack entities that are foreign to the individual's body. When there is inadequate GH, the thymus shrinks in size and the white cells don't do as good a job of locating, killing, and eating bacteria, viruses, and cancer cells. Certain of these white cells instruct other white cells (called B-cells) to make antibodies. This, too, is performed less well when there is inadequate GH.
Older people release less growth hormone than younger people do, and this is suspected by some scientists studying aging, including ourselves, to be an important factor in the rapid decline in health that occurs after young adulthood. It is possible to bring GH release back up to young-adult levels by taking supplements, including the nutrients L-tryptophan, L-arginine, and L-ornithine (amino acids) and the prescription drug L-Dopa (also an amino acid). Taking these just before bedtime increases GH release at a natural place in the daily cycle. Other stimulants of GH release include exercise, fasting, and hypoglycemia.
Reducing sleep without disturbing the brain's chemistry may be an effective strategy for life extension; even if we don't live any more years than is normal, we can increase our subjective life spans by up to about a third. Although it is possible for at least some individuals to function with very small amounts of sleep, data indicate that, for most of us, sleeping seven to eight hours a night is normal, and any substantial deviation from that amount is usually associated with a reduced life span.
Staying awake for prolonged periods results in a psychotic state (including hallucinations and paranoid delusions) that closely resembles that seen in chronic abusers of amphetamines. They both result in depletion of brain stores of norepinephrine, an important neurotransmitter. Staying awake for a couple of nights has been of benefit to some people with depression, possibly by a mechanism involving a resetting of day-night cycles. It is known that REM deprivation reduces the threshold for electrical shock convulsions. Thus, it may activate an overly inhibited (depressed) nervous system.
Finally, we'd like to close this column with a little sleep experiment you can try. Vitamin B-12 increases the brain's manufacture of RNA and has other interesting properties: it promotes the appearance of colored dreams! We and others have noted this when we have taken high doses of B-12 after a period of abstinence (you quickly develop tolerance to the effect). A dose of 1,000 micrograms is a reasonable adult dose that often, but not always, produces vivid, brightly colored dreams. They may be so vivid that they wake you up. It must be taken immediately before going to sleep and seems to work about half of the time. Sweet dreams (or, if you prefer, happy nocturnal hallucinations).
A list of scientific literature on this topic is available through REASON. Send a stamped, self-addressed envelope and ask for H&W references, March.
Durk Pearson and Sandy Shaw are consulting scientists, authors, and TV personalities. Copyright © 1982 by Durk Pearson and Sandy Shaw.