From The Desk Of Clarence Bass
Aging Memory Center Responds to Physical Exercise
Research Finds Exercise Beneficial for Brain, Diabetes, and Health Span
The benefits of exercise continue to multiply. We have a study showing stimulation of semantic memory, the accumulated knowledge of the world around us. Another on muscle strength in the prevention of Type 2 Diabetes. And third, a review paper on the role of resistance training in maximizing our years of independent living.
Stimulating Semantic Memory
I wrote about the plasticity of the brain in our book Challenge Yourself—At Any Age (Ripped Enterprises, 1999). Scientists once thought that our brain stops growing in adulthood and tends to shrink and grow dormant with age. We have since learned that the brain is plastic. With vigorous stimulation, even an older, developed brain can grow—respond to challenge.
Junyeon Won and colleagues from the Department of Kinesiology at the University of Maryland and elsewhere tested the effects of a single bout of acute exercise on semantic memory and reported their findings in the May 2, 2019, Journal of the International Neuropsychological Society.
If people lose semantic memory, they struggle with knowledge of everyday objects in the world, and have trouble communicating.
While it is increasingly recognized in young adults that an acute bout of exercise can improve short and long-term memory, the same has not been clearly established in healthy older adults.
The connection between exercise and semantic memory has received little attention.
“Given that the inability to remember familiar names is the most common memory complaint among older adults, investigating semantic memory may serve as a useful predictor of neurodegenerative disease,” the researchers wrote in introducing the study. “Considering that single bouts of exercise are the building blocks of chronic exercise, understanding the changes induced by acute exercise may provide novel insight into the association between exercise and memory,” they continued.
Won et al rotated 26 healthy men and women (age 55-85) between 30 minutes of rest and 30 minutes of stationary cycling immediately before performing a “Famous and Non-Famous” name discrimination task during MRI scanning. One week they rested quietly and the next they rode a stationary bike at a moderate pace. (They didn’t want fatigue to affect the test.) Afterward, they watched names—some famous and others from the local phone book—flash across a computer screen. An MRI brain scanner tracked activity as they keyed familiar and unfamiliar names.
The following appears in the “Discussion” portion of the study:
The MRI results provide evidence that an acute bout of aerobic exercise can influence semantic memory neural circuits in healthy older adults. Specifically, we have shown greater semantic memory activation following a single session of exercise compared to rest in several brain regions involved in semantic memory retrieval.
Greater brain activation following a single session of exercise suggests that exercise may increase neural processes underlying semantic memory activation in healthy older adults. These effects were localized to the known semantic memory network, and thus do not appear to reflect a general or widespread increase in brain blood flow. Coupled with our prior exercise training effects on semantic memory-related activation, these data suggest the acute increase in neural activation after exercise may provide a stimulus for adaptation over repeated exercise sessions.
Based on this plausible mechanism, we hypothesize that neural adaptations after daily bouts of exercise mediate exercise training-related cognitive improvement and enhanced brain function. The immediate and long-term clinical impacts of these findings are yet to be fully elucidated, but our data suggest that single sessions of exercise may be a stimulus to bolster the capacity of memory networks during successful memory retrieval, and support previous findings indicating exercise offers protection against age-related cognitive decline.
The scientists had expected a quieter response, senior researcher J. Carson Smith, director of the Exercise for Brain Health Lab at the University of Maryland, told New York Times health writer Gretchen Reynolds. That’s what generally happens after weeks of exercise.
On second thought, they began to think they were watching the start of a training response.
“There is an analogy to what happens with muscles,” Dr. Smith told Reynolds.
When people first begin exercising, he pointed out, their muscles strain and burn through energy. But as muscles become fitter they become more efficient and use less energy for the same workout.
The same appears to be true for the spike in brain activity after the first session of biking.
“Our brain’s memory centers become, in other words, more fit,” Gretchen Reynolds wrote.
The entire study is available online:
Muscle Strength and Type 2 Diabetes
We can add strength training to the established ways to prevent type 2 diabetes, allowing people a wider range of exercise, making it more likely they will enjoy their training and keep doing it.
A study reported in Mayo Clinic Proceedings (April 2019) examined the association between muscular strength and incidence of type 2 diabetes—independent of cardiorespiratory fitness (CRF). They found that moderate levels of muscular strength were associated with lower risk of T2D, separate and apart from CRF.
Practically any form of exercise done regularly is protective against T2D.
Photo by Wayne Gallasch
While it is well established that regular physical activity is associated with reduced risk of T2D, most research has focused on aerobic exercise. Much less is known about strength training and T2D. Moreover, studies that have focused on resistance training are often based of self-reporting and subject to recall and social bias.
Led by Yuehan Wang, Department of Kinesiology, Iowa State University, and overseen by Steven N. Blair, PED, formerly director of research at the Cooper Institute, the new study looked at the two forms of fitness separately.
A total of 4681 adults, aged 20 to 100 years, free of type 2 diabetes at baseline, underwent muscular strength tests and maximal treadmill exercise tests between January 1, 1981, and December 31, 2006, as part of comprehensive medical examinations at the Cooper Clinic in Dallas. Muscular strength was measured by the leg press and bench press and categorized by thirds (lower, middle, and upper) of the combined strength score. Type 2 diabetes was defined on the basis of fasting plasma glucose levels, insulin therapy, or physician diagnoses.
During a mean follow-up of 8.3 years, 229 of the 4681 patients (4.9%) had developed type 2 diabetes. Participants with the middle level of muscular strength had a 32% lower risk of developing type 2 diabetes compared with those with the lower level of muscular strength—after adjusting for estimated CRF.
“These results indicate that very high levels of RE training may not be necessary to obtain the considerable health benefits on T2D prevention,” the researchers concluded.
Second author Duck-chul Lee, PhD, also from Iowa State University, said in a press release that the results are encouraging, as they show that even small improvements in muscle strength may help prevent type 2 diabetes.
Coauthor Angelique G. Brellenthin, PhD, also from Iowa State University, said that increasing muscle strength offers several health benefits, even if "you're not necessarily going to see the results of resistance training on your bathroom scale."
She also emphasized that getting started with resistance exercise does not require expensive equipment or a gym membership.
"We want to encourage small amounts of resistance training, and it doesn't need to be complicated," she said.
"You can get a good resistance workout with squats, planks, or lunges. Then, as you build strength, you can consider adding free weights or weight machines."
This eases the burden of healthcare professionals in persuading patients to take up resistance training, perhaps combined with modest levels of aerobic exercise.
The co-author comments in the press release are reproduced in a Medscape commentary posted May 5, 2019.
Resistance Training Maximizes Health Span
A review paper by researchers at the University of Texas Medical Branch, Galveston, is highlighted in Dr. Richard Winett’s Master Trainer healthy living newsletter. No surprise. Winett has been waiting for this since he began strength training as a youth—and became an advocate for that form of exercise. Kaleen M. Lavin and colleagues from the UT Department of Nutrition and Metabolism give top billing to resistance training for combating neuromuscular aging.
“Older adults undergoing age-related decrements in muscle health can benefit substantially from resistance exercise training, a potent stimulus for whole muscle and myofiber hypertrophy, neuromuscular performance gains, and improved functional mobility,” Lavin et al concluded.
Professor Winett remembers the “aerobics revolution” kindled by Dr. Kenneth Cooper’s book Aerobics, published in 1968. Aerobic fitness became practically synonymous with health. Strength training was looked on as primarily cosmetic.
Resistance training builds the physique—and much more.
Photo by Bill Reynolds
“In this heavily referenced review article, however, Lavin and colleagues show based on the evidence that resistance training now should be the exercise of choice for older adults,” Winett wrote. “The benefits include increased strength which enables the relative ease in performing tasks of daily living; better balance to prevent falls; increased muscle mass which improves metabolism, and improved mood and cognitive ability.”
Winett’s bottom-line: “Here we are circa 2019 and we are finding out from experts in the field that resistance training is one of the best things we can be doing and is the exercise of choice.
Looking ahead, Lavin et al added: We expect RT to strengthen its position as an effective tool for maximizing health-span in the aging population.
For someone who has been lifting (and exercising) even longer than Dick Winett, this is all wonderful news.
I well remember my high school coach telling me not to lift weights; that athletes don’t train with weight. He didn’t mention getting muscle bound, but I knew that’s what he was thinking.
He went to school with my father in northern New Mexico, and used to joke that my dad could still out run me.
It just so happens that his daughter lives down the street from us. I met him again in the last months of his life, when he was visiting with her family. We didn’t talk about weight training, but he gave me a big hug.
I like to think that he knew how far weight training has taken me—and athletes everywhere. I’m pretty sure he was glad I kept lifting, when I led his team to victory in the state Pentathlon championship.
He might also have gotten word of the “Karpovich Conversion,” which exposed the muscle bound myth and turned the tide of weight training in athletics. I learned about it while I was still in high school. It was documented in a widely used college textbook for many years.
I wrote about it recently on our FAQ page: (scroll down to the piece on Flexibility)
As scientists keep coming out with good news on exercise—especially weight training—I’ll keep telling you about it.
I’d like to think that Coach and my dad are up there somewhere talking about old times—and the wonders of weight training.
June 1, 2019
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