Some people will do just about anything to live longer -- eat less meat, eat more chocolate, give up alcohol, drink a glass of red wine every day -- but that's all based on anecdotal evidence. A group of researchers at Washington University, though, may have made a breakthrough in the eternal quest for longer life.
They have discovered a link between lower core body temperature and a longer lifespan. Not only that, they've discovered that people who eat less have lower core body temperatures. Eureka! (Or something like that.)
Core temperature is defined as the temperature at which all body systems function at maximum efficiency. Though the average human being is said to have a core body temperature of 98.6 degrees Fahrenheit, the core body temperatures in individual humans can range from 96 to nearly 100 degrees.
In a recent study, the scientists discovered that a person's core body temperature is influenced by how many calories he or she consumes. A similar study with mice proved that the mice with lower core body temperatures lived up to 50 percent longer, though with mice, that only means a few months.
Ergo: humans with lower core body temperatures live longer, too. (This was actually proven by the Baltimore Longitudinal Study of Aging, though the lower body temperature of the longer-lived men in that study was due to genetics, not diet.)
"What we don't know is whether there is a cause/effect relationship or whether this is just an association," said principal investigator Dr. Luigi Fontana in a press release. "But in animal studies, it's been consistently true that those with lower core body temperatures live longer."
The Wash. U. study compared the core body temperatures of 24 people in their mid-50s who had spent at least six years on a restricted-calorie diet with 24 other people of roughly the same age who continued to eat a normal Western diet with the higher fat and calorie intake this implies. Just to make sure that body temperature wasn't linked to lower weight, the scientists threw into the mix 24 middle-aged endurance runners. They kept track of everybody's temperature with telemetric capsules that transmitted readings every minute.
"The people doing calorie restriction had a lower average core body temperature by about 0.2 degrees Celsius, which sounds like a modest reduction but is statistically significant and similar to the reduction we have observed in long-lived, calorie-restricted mice," Fontana said. "What is interesting about that is endurance athletes, who are the same age and are equally lean, don't have similar reductions in body temperature."
Unfortunately for people who like their food, it appears that reducing core body temperature with a reduced calorie intake is the only way to live longer. In yet another study, this one with mice, researchers discovered that while regular dips in cold water lowered body temperature, they had no effect on overall lifespan.
Sadly, Fontana believes that if people want to lower their body temperatures and live longer, they'll actually have to do some work.
"I don't think it ever will be possible to be overweight and smoking and drinking and then take a pill, or several pills, to lower body temperature and lengthen lifespan," he said. "What may be possible, however, is to do mild calorie restriction, to eat a very good diet, get mild exercise and then take a drug of some kind that could provide benefits similar to those seen in severe calorie restriction."