Another method of extending lifespan is reduction of body temperature. In the 1960s, Liu and Walford (at UCLA Medical Center) were able to extend the mean and maximum lifespan of cold-blooded fish by reducing their body temperature by several degrees. This was accomplished by putting the fish in a cold water tank, an approach that is not possible in warm-blood animals whose thermoregulatory system attempts to maintain normal body temperature under all conditions.
(Efforts by the UCLA scientists to lower body temperature in warm-blooded mice with marijuana and other chemical agents only achieved transitory results).
We've already seen that melatonin enables us to recuperate, and be revitalized and rejuvenated at night by inducing deep, restful sleep. One effect of the high levels of melatonin that circulate throughout our body at night is reduced body temperature in the wee hours of the morning when we normally experience our deepest level of sleep. Considering the lifespan-extending effect of reduced body temperature in fish, it may be that melatonin helps to maintain youthful function by lowering body temperature every night.
There have been studies in both men and women showing that body temperature is not lowered nearly as much during the night in older people, as their melatonin levels decline with advancing age. In a recent study by scientists at the University of California School of Medicine, San Diego, core body temperature was measured in 8 young women (22-32 years) and 6 older, post menopausal women (54-62 years) by a sensor inserted into the vagina.
Age Differences In Temperature Descent
They found that the nightly temperature descent produced by elevated levels of melatonin at night was steeper in the younger women. The mean temperature descent in the young women was 2.10 F. (to 96.50 F.) compared to only 1.20 F. in the older women (to 97.40 F.). This difference in temperature descent correlates with the sharp decline in melatonin levels with advancing age, which may be one of the causes of aging.
Melatonin Supplementation and Body Temperature
Since supplemental melatonin improves the quality of sleep, it suggests that taking melatonin should also help to maintain the temperature descent of youth. In another part of the University of California study, 7 young (22-32 years) women and 7 older (54-62 years) women were put into two groups and given high oral doses (100 mg) of melatonin or placebo in an attempt to determine the effects of melatonin supplementation on body temperature.
Results Of Study
They found that in young women, melatonin reduced body temperature significantly in young women, but produced only slight and inconsistent results in the older women. These findings mean little, however, because the women took melatonin at 8 AM in the morning rather than at night, when it acts to induce therapeutic sleep. Thus, we await another study to measure the effect on body temperature of the nightly administration of melatonin.
Combining Food Restriction and Temperature Reduction
When Liu and Walford were studying the lifespan-extending effects of temperature reduction in fish, they tried one experiment in which they restricted the food intake of the fish early in life and lowered their temperature late in life. The combined effects of these two regimens enabled them to triple the lifespan of the fish!
This experiment, which has never been repeated, suggests that the appropriate combination of existing lifespan-extending therapies could have synergistic effects exceeding that of any single therapy. What's needed is a major research program aimed at discovering the most effective combinations of anti-aging therapies.
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