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Leg Power Brain Power

written by Risë’s Pieces |

We were made for exertion.

Jesus told a parable in which a lord, about to travel to a far country, called three of his servants before he left, and gave each of them talents. The one who had received five talents, used them. The one who received two talents did something with them. But the third servant chose to sit on his. His became a sedentary talent.

When the lord came back, the one who had received five brought five more talents. He said to the lord, “You gave me five, and look, I gained five more.” The one with two talents doubled his, also. But, the sedentary talent from the servant who the lord described as lazy, gained nothing.

This parable is just as true physiologically as it is spiritually, economically, or any other way. Our physical body is a talent. What we do with our talent literally causes increase in other areas. For example, researchers have found that developing muscle strength—especially in the legs—is the most effective way to improve cognitive function. Thankfully, muscle strength is not the same as muscle mass. In other words, we may not look like the gym bros, but may still have strong legs from intentionally doing leg exercises, and having strong quads. Squats or deadlifts don’t just make muscles stronger, these talents are growing elsewhere, like the brain.

Researchers from King’s College in London followed 324 female twins for ten years. The researchers found that the twin with stronger leg muscles had significantly better cognitive function than the sedentary twin. Stronger legs equated to sharper minds. Leg power correlated with increased gray matter volume and enhanced brain activity!1

Believe it or not, one of the mechanisms for leg power leading to a larger hippocampus involves lactate—and for our purposes here, basically the same as lactic acid. Our muscles produce lactate when they are exerted past their ability to easily make energy from glucose and oxygen. Lactate actually travels from the muscle into our blood and is consumed by the brain for energy. Lactate is a signaling molecule that communicates to the brain how hard our muscles are working. Then, the brain and body respond by turning on all kinds of healing, empowering stuff to raise the bar.

 Lactate activates Brain-Derived Neurotrophic Factor (BDNF) in the brain. BDNF has been likened to brain fertilizer because of its ability to increase growth of new neurons, strengthen connections between brain cells, help with memory and cognition, and improve neuroplasticity. High levels of lactate have actually been shown to improve cognition scores, impulse control, serotonin levels, and support focus and attention. In response to our muscles being exerted past what’s easily doable, when they are being stressed or pushed during intense exercise or physical activity, we are literally producing other talents.

What happens to those who sit on their talent of physicality and live a sedentary life? Research, and systematic review of research, has found that physical frailty and physical inactivity have a relationship to cognitive impairment—including Alzheimer’s disease. A systematic review of 15 studies observed that poor grip strength was associated with more risk of cognitive decline and dementia.2 Those with poorer strength had more risk of Alzheimer’s disease.3

The good news is that it’s not too late to use our talent of physicality. By gradually increasing the intensity, speed, duration, and load, our little can become much.

  1. Claire J. Steves, Mitul M. Mehta, Stephen H.D. Jackson, Tim D. Spector; Kicking Back Cognitive Ageing: Leg Power Predicts Cognitive Ageing after Ten Years in Older Female Twins. Gerontology 1 February 2016; 62 (2): 138–149. https://doi.org/10.1159/000441029
  2. Robinson, T.L., Gogniat, M.A. & Miller, L.S. Frailty and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis of Cross-Sectional Studies. Neuropsychol Rev 32, 274–293 (2022). https://doi.org/10.1007/s11065-021-09497-1
  3. Cui M, Zhang S, Liu Y, Gang X, Wang G. Grip Strength and the Risk of Cognitive Decline and Dementia: A Systematic Review and Meta-Analysis of Longitudinal Cohort Studies. Front Aging Neurosci. 2021 Feb 4;13:625551. https://pmc.ncbi.nlm.nih.gov/articles/PMC7890203/