There is a common saying “Live Fast and Die Young” however, the contrary is equally true – Live slow and Die Old.
Tortoises are reptiles that can live to an advanced age. Their main secret for longevity is a low metabolism and not their slow speed. However, both low speed and metabolism are connected. It is a general rule. Most animals with a high metabolic rate tend to die early in comparison to those who burn energy slowly. In other words, the more responsive an animal is the higher will its metabolic rate be. This is so to supply sufficient energy to sustain its’ body activity.
An example could be the shrew or hummingbirds, which are highly active and live only to around 2 years. On the other hand, Giant Tortoises consume energy at a much lower pace and can therefore, live up to their eighteenth or twentieth decade. Jared Diamond who is an UCLA-based physiologist says that metabolic rates vary across species. The metabolic rate can within only the category of vertebrates differ by 10 million times.
Researchers commonly measure animals’ metabolic rate by analysing the level of oxygen they gulp while they walk on treadmills. According to Armand Leroi who is an evolutionary developmental biologist at Imperial College, London says that measuring metabolic rate is “trickier with some animals than others”
Scientists do know that low metabolic rate is associates with longer lifespan. However, it is still unknown why a drop in metabolic rate is really connected with longevity.
There is a general opinion that aging is caused by free radicals, which are reactive molecules emitted in the body when fuel (food, etc….) is burned. According to Leroi, there are a number of proofs showing that free radicals do cause oxidative and DNA damage.
The controversy is that slowing down the metabolism would not assure longevity. According to Leroi, you would still “die from any number of things”.