Bernard Lagat just won the Master’s men’s mile at the 2015 Millrose games . His accomplishment is certainly a testament to proper training and its effects upon enduring speed and endurance as one ages. To further expose a growing pool of findings about what can be achieved as age progresses, a recent study published in the journal PLOS ONE found that older individuals who run several times per week expend the same amount of energy, when they walk, as compared to 20 year olds.
A distinctive characteristic of impaired walking performance among older adults is a 15–20% greater metabolic cost for walking (worse economy) compared to young adults. In addition, impaired walking performance is a key predictor of survival rates and life expectancy among older adults
In this study, researchers from the University of Colorado Boulder and Humboldt State University studied 30 healthy older adults, average age 69, who regularly walked or ran for exercise 30 or more minutes per day, 3 times per week. During the study, participants walked on a treadmill at varying speeds while their oxygen consumption and carbon dioxide production were analyzed.
The runners had similar energy expenditure in comparison to a group of young adults in their 20s from a previous study. However, the elderly participants who walked regularly did not see that same benefit, and expended up to 22% more energy than the young adults.
The authors surmise that heightened muscular efficiency may help explain why older runners have a lower metabolic cost of walking. As one ages, there is a reduction of ATP synthesis per O2 uptake which effectively reduces muscular efficiency and therefore increases the metabolic cost of muscle activation
However, recent evidence suggests that aerobic exercise training may ameliorate mitochondrial uncoupling and improve muscular efficiency in older adults
The authors acknowledge that it is unknown whether there is “an intensity threshold of aerobic exercise that is needed to prevent the decline in walking economy.” However, the knowledge from this study is useful in helping to prevent some of the degenerative side effects of old age and prompts one to lace up those shoes and keep on running!