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07.05.2009

Creatine is pep pill for elderly

Elderly people who take creatine [structure below] have more energy and strength when it comes to physical exertion, researchers at the University of Oklahoma discovered when they did tests on fifteen people in their seventies.

The subjects did no training. They were given twenty grams of creatine daily for a week, and then ten grams of creatine per day for five weeks. The creatine was divided up into five-gram doses spread over the day.

Before starting to take the supplement, the researchers measured the subjects' muscle strength by getting them to stand up and sit down for as long as they could, and to do hand grip exercises. The six-week creatine course had no effect on the number of times that the subjects could stand up, but the strength in their hands increased, by seven percent. This is illustrated in the figure below. White = before; black = after.

The researchers also got their test subjects to cycle with electrodes attached to their leg muscles. This enabled the researchers to measure the strength with which the nerves stimulated the muscle tissue. When people use their muscles, the intensity of the electrical stimuli from the nerves to the muscles increases as the muscles become tired. The stronger stimuli are probably needed to activate muscle fibres that have been inactive until that moment.

The researchers got their subjects to cycle a couple of times consecutively as fast as their heart rate would allow. They measured how tired the subjects were through the electrodes. This way the researchers could measure their subjects' physical working capacity at fatigue threshold (PWCFT). The creatine supplement had a statistically significant effect on this too. The PWCFT increased by sixteen percent.

That creatine increases strength is already known. The effect on the PWCFT is more interesting. The researchers ascribe this to the effect of "elevated muscle phosphocreatine (PCr) on the transition from anaerobic to aerobic metabolism. Increasing muscle PCr content by CR supplementation may decrease the reliance on anaerobic glycolysis, reduce intramuscular lactate and ammonia accumulation, and therefore, delay the onset of fatigue", the researchers write. "Based on these results, perhaps very frail elderly men and women should supplement creatine seven to fourteen days prior to starting an exercise program to improve quality of training."

Source:
J Nutr Health Aging. 2007 Nov-Dec;11(6):459-64.

More:
Creatine extends lifespan of mice 08.10.2008