These days, with all the efforts that are being made to combat climate change, the watchword for every kind of transport is fuel efficiency. The world’s favourite environmentalist, Jeremy Clarkson, believes that hydrogen fuel cells are the answer to non-polluting car power; other people think it should be electric cars powered by sustainably generated electricity - or solar powered cars, even. Until any of those things happen, though, it will still be all about fuel efficiency. And now, it seems, fuel efficiency is something Silver Grey athletes can aim at and benefit from.


So, what is human fuel efficiency? Fuel efficiency is the term given to the rate at which muscular activity uses oxygen. Muscular activity could be any kind of bodily movement whether it is something obvious and aerobic like running, or something less obvious like walking to the shops or gardening. This rate at which oxygen is used is also known as the “Metabolic Cost” of activity, and in respect to running is known as Running Economy.


In order to find out more about people’s fuel efficiency and how it changes with age, researchers at University of Colorado, led by associate professor of kinesiology at Humboldt State University Justus Ortega have been doing some tests on two groups of 15 runners, one group aged in their twenties and the other group aged sixty five and older.


Both groups were regular runners, minimum 3 times per week for 30 minutes and over at least the previous six months. For the study, both groups were tested, across a range of speeds, on a special treadmill which measured the amount of force that the user applies to the running deck. Participants ran 5-minute sessions, at 2.01, 2.46 and 2.91 meters per second (4.5-6.5 mph).


After the tests the fuel efficiency of the two age groups was compared in order to discover what effect age has on it. Surprisingly, they found that the older runners had a similar metabolic cost of running as did the younger group. That’s to say that the rate at which the older group of runners burned oxygen was similar to that of the twenty year olds. And unsurprisingly, this is quite a different result from studies which examined the fuel efficiency of older adults who had an inactive lifestyle. These previous studies have shown that muscles become less efficient with age in those people who do have a sedentary active lifestyle, so the different findings of this new study can be put down to the fact of the older group’s running.


Researchers did find that there were bio-mechanical differences in the running characteristics of the older group, but even so older runners consumed metabolic energy at a similar rate to the young runners across the range of speeds. Essentially, these older runners maintained what was described as “youthful running economy” into their 60s.


When reading about this, we wondered about the importance and relevance of these results. After all, not everyone wants just to be good at running. And even if you are one of the people who do want to be good at it, why should it be something that matters to anyone who doesn’t want to be an efficient runner? Why is this important?


Our question to ourselves was whether the importance of this fuel efficiency, which was created in the research group by their regularly going running, might not be the translation of the improvement in muscle function into everyday life, into everyday activities that depend on muscles for execution.


We contacted Professor Ortega with our question who replied with this. “The positive effects of running (improved muscle efficiency, improved range of motion, improved cardiovascular health - and some even argue improve motor control i.e. balance and muscle steadiness - do indeed translate to other activities; both of daily living and exercises such as walking and biking.” And to quote the report’s conclusions “It may be that vigorous exercise, such as running, prevents the age related deterioration of muscular efficiency and, therefore, may make everyday activities easier.”


So this is the importance of the research. Not that people who run at a more advanced age can continue to run, but that the running has a beneficial effect on the runners’ muscles, making life in general easier for older adults and ensuring that they continue to function more effectively and more independently at a time of life when people who let things slide will really feel the consequences.


And if you don’t like running in particular, you may be in luck. Professor Ortega and his team are looking at which other types of exercise have similar effects on your muscles, and also whether the benefits of vigorous exercise will be felt by sedentary people who decide to take up exercise at an older age.


We will wait to read about what the scientists find out, but even before we read it we’re pretty sure we know what the answer will be!

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