Have you ever had a moment when a word or the name of someone is on the tip of your tongue, but you just can’t retrieve it? We all have. Some people refer to these memory slips as “senior moments” and they’re quite common. The ability to retrieve words from the dark recesses of your brain declines with age, so those moments become more prevalent as we age. Fortunately, they don’t mean you’re on the path to Alzheimer’s disease. It’s a natural part of growing older, and even young people occasionally have problems remembering a word or a name.
Here’s the good news. Being aerobically fit may reduce the frequency with which you have to wrack your brain to retrieve something that’s “right on the tip of your tongue.” How do we know this?
Those Tip of Tongue Moments Put to the Test
Researchers at the University of Birmingham, the University of Leuven in Belgium, and King’s College designed an experiment to quantify those “tip of the tongue” moments. Then, they asked 28 older, healthy adults to come up with the names of various famous people and to identify words. The subjects also took part in an ergometer cycling study to measure their V02 max or aerobic capacity. V02 max is a measure of the quantity of oxygen a subject can use during exercise. People with higher V02 max have better aerobic capacity or the ability to sustain sub-maximal exercise.
Interestingly, the better the subjects’ aerobic capacity, the less likely they were to have problems retrieving names and words when prompted. They were better able to retrieve the information stored somewhere in their brain and regurgitate it. Hence, fewer memory slips and tip of the tongue, senior moments. Although this study doesn’t show cause and effect, it does suggest that developing greater aerobic fitness through sustained exercise that boosts the heart rate is beneficial for word retrieval.
Exercise and Brain Aging
Although those senior moments aren’t a precursor to Alzheimer’s, they become more common as we age. One of the markers of brain aging is a decline in brain volume. The area of the brain most impacted by aging is the hippocampus. Although small in size, the hippocampus plays a key role in learning and the formation of new memories. You have two hippocampi, one on each side of your head. Collectively, they make up the hippocampus. When you lose volume in these areas, you might expect some reduction in the efficiency with which your brain forms new memories and the ease with which it retrieves them.
Imaging studies of the brain show the hippocampus loses about 13% of its volume between the ages of 30 and 80. This may explain why memory retrieval declines with age. On the plus side, research shows the hippocampus is a portion of the brain most impacted by exercise. In animal studies, exercise stimulates the development of new nerve cells and new nerve cell connections in this portion of the brain. Exercise is almost like “fertilizer” for the hippocampus. Some studies in humans demonstrate this as well, although the results are less consistent. Some studies show exercise increases the size of the left hippocampus but not the right.
If aerobic exercise boosts hippocampal volume in humans, it doesn’t take extreme amounts of exercise to do it. In a study, 120 sedentary, older adults walked for 40 minutes 3 days per week. Imaging studies looked at their brain volume before and after a year of walking. The adults who walked regularly displayed a boost in the size of their hippocampus. The control group, who only stretched, did not. The researchers estimate the change in the size of the hippocampus was equivalent to reversing brain aging by 1 to 2 years. This study suggests that the hippocampus in the brain has “plasticity,” the ability to remodel itself some extent based on environmental and lifestyle exposures. The subjects in the study also had higher levels of some growth factors that boost brain volume.
Irrespective of brain volume, exercise may aid memory in other ways. Working out helps to reduce blood pressure and insulin resistance. High blood pressure and insulin resistance have a negative effect on brain health. Exercise also has an anti-inflammatory effect, which is healthy for brain cells. Plus, a heart-thumping workout helps alleviate stress. Being under stress can negatively impact memory as well.
What about Resistance Training?
With so much focus on aerobic exercise, you might wonder whether resistance training has memory benefits too. A study published in Acta Psychologica asked participants who had done leg extension exercises beforehand (6 sets of 10 reps) to recall a set of images. The other group was asked to recall the images without exercising beforehand. In a second session, two days later, the subjects were exposed to new images and asked whether they had seen the images in the first session. The group that performed leg extensions could correctly identify 10% more images than those who didn’t exercise.
Another study published in the Archives of Internal Medicine, older women with mild memory impairment enjoyed improvements in various aspects of memory function after 6 months of resistance training two times per week. The control group who did balance and toning exercises didn’t show the same improvement. It’s less clear-cut how resistance training enhances memory, but preliminarily it looks like it may have subtle memory-boosting benefits.
The Bottom Line
Exercise is a prescription for better health, including brain health. There’s no guarantee it will give you a bionic memory, but it could reduce the number of times that you struggle to remember the name of someone you know!
References:
· Psychology Today. “Study: Aerobic Exercise Leads to Remarkable Brain Changes”
· University of Birmingham. “Higher aerobic fitness levels are associated with better word production skills in healthy older adults”
· Front Aging Neurosci. 2018; 10: 63.
· VeryWell Mind. “Hippocampus Role in the Limbic System”
· NeuroImage. Volume 166, 1 February 2018, Pages 230-238.
· Harvard Health Publishing. “Regular exercise changes the brain to improve memory, thinking skills”
· Scientific American Blog. “Aerobic exercise bulks up hippocampus, improving memory in older adults”
· Neurology. April 15, 2014; 82 (15)
· Arch Intern Med. 2012 Apr 23; 172(8): 666–668.
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