Caloric Restriction, Lower Body Temperature, and Longevity

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Previous studies have demonstrated that animals that consume fewer calories live significantly longer than littermates eating a standard diet. Part of the findings also identified the animals consuming the restricted diets had a lower core temperature, causing postulations as to a relationship. Now researchers at Washington University in St. Louis have published a paper in the journal Aging documenting that people on restricted caloric diets present with a lower core temperature as well. In the study three experimental groups had body temperatures monitored telemetrically. One group of 24 individuals over 50 years of age, who had consumed restricted caloric intakes (25% or more) for over 6 years, were compared to another group of 24 individuals of the same age who consumed a traditional Western diet with a higher caloric intake and increased fat content. These two groups in turn were compared to a group of distance runners, all over 50, to determine if leanness was a factor influencing core temperature, rather than the caloric intake. The results showed that only the group on a restricted caloric intake had a decrease in average core temperature. Although the 0.2 degrees Celsius difference was small numerically, it was statistically significant. The researchers have not determined a causal effect for the reduction in calories effecting the temperature change, but note that the lower temperature seems to be crucial to increased longevity found in animals and humans. Citing a previous study, the authors suggest that men with lower body temperatures live significantly longer than those with a higher body temperature. The way in which body temperature is lowered may be significant as well. Other studies in which animals were exposed to cold water for regular swimming sessions (reducing body temperature) did not live any longer than those who do not experience the cold water exposure. In summary, restricting caloric intake results in a lower core body temperature which may be key to an increased life expectancy. Leanness and external factors lowering body temperature are not expected to produce the same outcome.(Aging, 2011)
National Council on Strength and Fitness