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avoid unnecessary muscular exertion .
A cheetah running at 120 km per hour in short bursts with every muscle in action is energetically understandable because losing the dinner would be a far more serious matter than expending some energy . That is why cheetahs usually just walk to maintain efficient low energy expenditure .
Slow metabolism We , humans and our primate cousins , however , possess a great secret advantage . We hold a far slower metabolism . During an average day , we expend 50 % less energy than other mammals of equivalent weight . To date , scientists cannot explain this huge physiological energetic gap .
Humans would need to run a marathon every day to be on the same level of energy expenditure with non-primates mammals , like cheetahs . Nobody knows how and why primates came to expend so little energy .
Interestingly , it has been suggested that our ‘ slow metabolism ’ evolved to cope with the frequent shortages of food suffered by our ancestors . Orang-utans burn their fat stores and slow down their metabolism during the shortages when caloric intake is less than expenditure .
Essence of Life True , a slow metabolism bears beneficial effects , such as slow growth and long life , but there are also negative aspects to tackle . Take for instance the obesity epidemic that affects one-third of the population in the industrialised countries . Some scientists argue that it is our inherited ‘ slow metabolism ’ that makes us prone to get fat , reducing to insupportable levels the amount of calories daily burned in absence of exercise . Within the mammalian family , physical activity is not always directly linked to energy consumption as it is generally thought . Metabolism activity greatly interferes and modulates the balance between food absorption and calories expenditure .
On equal terms of food intake , a slow metabolism requires a higher level of physical activity . The role exercise played in the evolutionary past of the human race is deeply grounded in the unassailable persistence of a slow metabolism . So , we were born to run . Millions of years of natural selection designed us to run so that we could hunt .
Our forefather ’ s hunting strategy , developed
more than 2 million years ago , was based not on speed but on endurance , the ability to chase an animal for endless kilometres , to force it to run until it eventually collapsed due to overheating . Unknowingly , this activity led the foundation of our cognitive skills . So for humans the significance of running holds the ultimate value of a refined intelligence . In the long run , literally , it represents our essence .
Olympic feet Despite human excellence as running hunters , four animal species could beat a person over a marathon , but , curiously , not the horse .
Horses fare much better than men over about half a marathon ( 21 km ) and that ’ s why they were used for the Pony Express mail service in USA before the invention of the telegraph in 1862 . Each horse travelled for about an hour between two stations covering on average 24 kilometres and the rider would change the horse at each station . After 30 km humans get some advantage on horses .
Every year , in the Welsh town of Llanwrtyd Wells , a race is held named ‘ Man versus Horse Marathon ’. It has been run for 33 years . A human has beaten the horse only twice , but the race is about 35 kilometres , not the 42 kilometres of a full Olympic marathon distance . Humans endure longer distances better than horses . Our prowess over long distance relies mainly on our ability to avoid overheating , accomplished through sweating and being hairless .
Second position Another long-haul racer , not surprisingly , is the Siberian husky dog .
During the Iditarod trail dog sled held annually in Alaska , the husky dogs pull the sled for around 6 hours a day at the speed of about 24 kilometres per hour , meeting a total of 144 km a day .
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