If it’s ever been difficult to think while exercising, a new Texas A&M Health Science Center School of Public Health study may point to the reason why.
The study shows that mental weariness among older women causes a dip in brain activity while continuously performing a strenuous task. The authors hypothesize that the decreases may indicate that the area of the brain most associated with decision making, the prefrontal cortex (PFC), is compensating by recruiting other regions in order to maintain motor performance.
The study recently published in the Journal of NeuroEngineering and Rehabilitation found that mentally fatigued women with an average age of 75, while having about the same performance physically as when they were not mentally fatigued, had greater decreases in oxygenated hemoglobin in the PFC.
“When you see decrements in the prefrontal cortex, it could mean a number of things,” Ms. Ashley Shortz, doctoral student at the Texas A&M School of Public Health and first author of the study said. “When you see the decrease [in hemoglobin] in a particular brain region, it can either mean that they’re not using that specific region for the task, or that there is a transfer in the region that the blood is being pushed to. We suspect there is a transfer.”
Ms. Shortz had participants take cognitive tests for an hour in order to induce mental fatigue, after which they would alternate between gripping a dynamometer with their hands and resting. Hand-held dynamometers are used for routine screening of grip and hand strength.
Ms. Shortz kept to a participant group of females around the age of 75 because of age and gender differences in response to fatigue.
“Most research that you see going on in universities typically looks at young healthy subjects, simply because that’s the easiest group to recruit,” Ms. Shortz said. “But understanding the changes in both physical and cognitive capabilities with the normal aging process in our older population is very important, because the population of those 65 and above is rapidly growing.”
“Anything that you do as a younger adult, unless you are training those functions, are typically going to decline as you get older,” Ms. Shortz said. “Slowing down those declines by staying mentally and physically fit will help individuals in the long run.”
Ms. Shortz and others from the NeuroErgonomics lab at the Texas A&M School of Public Health where the research was conducted want to slow the declines by encouraging mental fitness as a supplement to physical fitness.
“Our hopes for this [study] is that those working on healthy aging interventions will take these findings into consideration and develop some sort of mental training, or brain games aspect into their healthy aging interventions,” Shortz said.