Research shows surprising link between weightlifting and cognition

By John Murphy, MDLinx
Published August 15, 2019

Key Takeaways

In a new study in the Journal of Applied Physiology, researchers demonstrated that weight training can overcome cognitive impairment and even jumpstart the creation of new neurons. Just three resistance-training workouts a week were enough to improve cognition and boost memory performance in “gym rats.”

But in this study, the “gym rats” were actual rats. Lab rats, to be precise.

Of course, this doesn’t mean that humans who weight-train will get the same brain gains. Nevertheless, the researchers suspect that strengthening exercises may very well counteract age-related cognitive impairment and memory loss in humans.

Strong muscles, stronger mind

A good deal of previous research led up to this study. Other investigators have found indications that resistance training in humans heightens IGF-1 signaling—an indicator of neurogenesis—and increases neuroplasticity. But no previous researchers had ever really mapped out the molecular signaling process that connects resistance training to improved cognitive function and memory.

To discover these molecular changes, the current study researchers first needed rats with cognitive impairment. Because neuroinflammation precedes age-related cognitive impairment, the researchers created inflammation in the rats’ brains by injecting a type of fat that induced neuroinflammation in the rodents.

Then it was time for weight training. Since it’s very likely impossible to coach rats to lift little dumbbells—especially rats who are cognitively impaired—the researchers instead attached small weights to the rats’ hindquarters and trained the rodents to climb a 3-foot high ladder. Doing several sets of this activity a few times per day, 3 days per week, had the effect of strength training. Soon, the rats were building muscles. As their strength increased, the rats were given progressively heavier weights.

Another group of rats (the sedentary group) also had induced neuroinflammation, but did not have to do resistance training. A third group of rats (the control group) had sham training but weren’t given the fat injection to the brain, so they weren’t cognitively impaired.

At 5 weeks, the researchers gave the three groups of rats a memory test in a maze. As expected, the cognitively impaired rats had more trouble than the unimpaired control rats. But after a few days, the cognitively impaired rats who had done strength training matched—and in some cases exceeded—the ability of the control rats. The sedentary rats lagged far behind.

To the researchers, this indicated that weight training was able to reverse the impairment caused by neuroinflammation, even though the inflammation in their brains was still present.

Examination of the rats’ brains showed increased activity in downstream IGF-1 signaling, indicating new neurons were generated. The researchers also found molecular signs of increased neuroplasticity, suggesting that the weight-trained rats had recovered some brain function despite their cognitive impairment.

“This model offers a potential therapy that may prevent or delay the onset of mild cognitive impairment in neurodegenerative diseases that warrants further investigation,” the authors concluded.

That’s great news for rats. But will it work in humans?

Go ahead and lift weights

As the study authors wrote, more research needs to be done. In the meantime, they added, weight training to stave off age-related cognitive impairment and memory loss is certainly worth trying.

“This is an option for the elderly,” Frank W. Booth, PhD, professor, Department of Biomedical Sciences, University of Missouri, Columbia, MO, said to the Columbia Daily Tribune. Dr. Booth was one of the authors and he funded the study out of his own pocket. “You see old individuals just sitting around. If they start using their muscles, it will be helpful to society.”

In an interview with The New York Times, lead author and doctoral candidate Taylor Kelty said: “I think it’s safe to say that people should look into doing some resistance training. It’s good for you for all kinds of other reasons, and it appears to be neuroprotective. And who doesn’t want a healthy brain?”

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