Tag Archives: ageing

Keep running to walk better

A number of physiological parameters, such as VO2max and lactate threshold, describe your ability to run well. Most of them decline as you get older, except for running economy. Running economy is the energy you spend to run at a given speed, in other words: it corresponds to what it costs your metabolism to make the movements.medium_14682933349

Studies have shown that older runners are just as economical as younger ones. Walking economy on the other hand becomes worse in people who use to walk for exercise just as it does in sedentary people. A paper published in PloSOne by Justus Ortega now suggests that running will allow you to keep the cost of walking down.

This is much more important than you might think because keeping the ability to walk easily is essential if you want to live independently in your old age. Moreover, there is a correlation between losing this ability and getting ill, showing how important it is for your life expectancy.

To find out what you can do to keep the cost of walking down, Justus Ortega and his colleagues compared the cost of walking of 15 older walkers with that of 15 older runners. (You can read the article for free if you want to know how they did it exactly.) They showed that the older runners’ cost of walking was much better than the older walkers’ and, of course, than sedentary older people’s. It was just as good as that of young sedentary adults.

What influences running/walking economy?

Your muscles and tendons have to be able to store and release elastic energy, they have to fire at the right moment and work together effectively to support your body weight, do the work, maintain your balance and allow the leg swing.

Your economy is also determined by the ability of your muscles to produce energy, such as the number and efficiency of your mitochondria and their enzymes.

Why older runners keep their walking cost low is not clear, but Justus Ortega and his colleagues suggest that the intensity of exercise is crucial. They think you might have to exercise harder, longer or more frequently if you want to keep your cost down. This would confirm a previous study, where elderly women performing high intensity walking workouts improved their economy by about 20%.  On the other hand, a year-long fitness program including strength and balance exercises did not have any effect.

Can I believe this?

This is an observational study, and just like any other observational study it does not prove cause and effect. In other words: the runners might have a better walking economy for reasons not related to running at all. Maybe they have become runners instead of walkers because their exercise economy was better due to a more favourable genetic profile.

Furthermore, this is a small study, and the results might simply be due to chance –or bad luck- while in de general population there is no difference.

It is clear that we need further studies, but in the meanwhile it is a good idea to have a healthy balance between high and low intensity exercise.

Disclaimer: this article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider

References:

Elbaz A, Sabia S, Brunner E et al. Association of walking speed in late midlife with mortality: results from the Whitehall II cohort study. Age (Dordr) 2013; 35(3): 943-52.

Ortega J, Beck O and Roby J. Running for exercise mitigates age-related deterioration of walking economy. PloSOne 2014; doi: 10.1371/journal.pone. 0113471. (accessed: 28/12/2014).

Milan OS, Thom JM, Ardigo LP et al. Effect of a 12-month physical conditioning programme on the metabolic cost of walking in healthy older adults. Eur J Appl. Physiol. 2007; 100: 499-505.

Saunders PU, Pyne DB, Telford RD and Hawley JA. Factors influencing running economy in trained distance runners. Sports Med. 2004; 34(7):465-85.

Thomas E, De Vito G and Macaluso A. Speed training with body weight unloading improves walking energy cost and maximal speed in 75- to 85- year old healthy women. J Appl Physiol. 2007; 103(5): 1598-603.

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