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- A new study shows exercise improves memory even without ketone production.
- Genetically changed mice without ketones still gained brain benefits from 8 weeks of exercise.
- Regular aerobic activity boosts brain cell power plants (mitochondria) and BDNF, improving mental performance.
- The brain can use other fuel sources during exercise besides glucose or ketones.
- These findings may change treatment ideas for Alzheimer’s, liver disease, and diabetes.
Exercise and Brain Health: Can It Work Without Ketones?
If you’ve ever thought that not having ketones or having problems with metabolism made exercise less good for your brain, think again. New research shows that moving your body can still improve memory and thinking even when your body’s usual metabolic backups—like ketones—aren’t there. If you have liver problems, diabetes, or are just trying to move past the keto trend, this could be really good news for your brain.
The New Findings: Memory Protection Without Ketones
A recent study changed how we thought about ketones and thinking, especially where exercise meets brain health. In this study, researchers used mice that were genetically changed so their bodies could not make ketones as a backup energy source when under metabolic stress. These mice could not make any ketones. But they still did eight weeks of exercise on a treadmill. And they still showed clear improvements in memory when compared with mice that did not exercise.
These results add strong proof to the idea that the brain benefits linked to moving aren’t only because of ketones. Improvements were clear in tasks that tested memory for where objects were placed and recognizing objects. Both of these are good ways to measure the health of the hippocampus, the part of the brain very important for making memories López et al., 2024.
Insight: Exercise helps memory even without ketone metabolism working.
This study goes against some old ideas. It strongly suggests that your brain’s ability to change, especially when you move your body regularly, matters more than having ketones for keeping memory sharp.
Ketones 101: What They Are and Why They Matter
To understand this important finding, let’s talk about ketones first. These are energy molecules—like beta-hydroxybutyrate (BHB), acetoacetate, and acetone. The liver makes them mainly when there isn’t much glucose available. This happens when you are fasting, exercising for a long time, or eating a ketogenic diet. Think of them as a different fuel source instead of glucose. They are especially good at powering parts of the body that need a lot of energy, like the brain.
For years, people thought ketones were very important for keeping your thinking clear when your body was under metabolic stress. Studies showed they helped make energy factories in the brain work better and lowered cell damage. Both are important for thinking well and keeping the brain healthy over time Jensen et al., 2020. This led many people to use ketogenic diets for brain problems like epilepsy, Alzheimer’s, and even depression.
But the latest findings suggest that while ketones are useful, you don’t absolutely need them. Your brain has systems that do much more than just use ketones. It can get mental strength from other things that happen when you move your body. This new information changes ongoing talks about memory and exercise. It also changes the growing talk about ketones and thinking.
Liver-Brain Energy Axis: A Key Team
Your liver is a main chemical factory for your body. It also acts like a remote control for how much energy goes to your brain. The liver helps control glucose levels. And it makes ketones when there isn’t enough energy. This liver-brain energy team is very important when you are fasting, sick, or under metabolic stress. This is when the brain’s main fuel—glucose—is low.
But if someone has liver problems or insulin resistance, they might make fewer ketones. This can affect how well the brain gets the energy it needs. This matters a lot for diseases like Alzheimer’s. In Alzheimer’s, the brain doesn’t take in glucose well. People thought ketones could help make up for this lack of energy. And traditionally, people thought not having this backup energy source would make thinking problems get worse faster.
But the recent study by López shifts this idea. It shows the brain can change from the inside. And it can still handle energy problems through things that happen because of moving your body. Simply put, exercise may “fill the energy gap” that happens when the liver-brain metabolic team isn’t working well.
The Study Design That Changed the Talk
Let’s look at how this important study was done.
Scientists changed the genes of mice. They made it so the mice didn’t have a key enzyme needed to make ketones. These mice could not make ketones at all. This was true even if they were fasting or exercising hard. The mice in the study and a control group were put on the same treadmill running plan. This plan was like moderate aerobic exercise for people. It lasted eight weeks.
Afterward, the mice were tested on memory tasks involving location and recognizing objects. The mice that couldn’t make ketones did just as well as the control mice. Key areas of the brain for thinking, like the hippocampus and prefrontal cortex, stayed healthy. These results clearly show that the brain benefits from regular exercise do not depend on having high ketone levels López et al., 2024.
Takeaway: Exercise helps the brain get better using other ways besides ketones.
This finding not only helps us understand memory and exercise more, but it also opens up new ways to help people who cannot rely on ketones for health benefits.
Exercise as a Brain Helper: The Cell Factory Boost
So, if ketones aren’t behind these good brain changes, what is?
The answer is how exercise changes cells. The main ways are by making more mitochondria and increasing levels of brain-derived neurotrophic factor (BDNF). Mitochondrial biogenesis means making new mitochondria. These are like tiny energy factories inside your cells. In the brain, having more mitochondria means brain cells have more power. This helps them work better, communicate better, and be stronger.
Exercise also increases BDNF. People often call BDNF “fertilizer for the brain.” BDNF helps new brain cells grow, stay alive, and connect. High BDNF levels are linked to better learning, memory, and thinking flexibility Erickson et al., 2011.
These cell and molecule responses to moving your body create a strong environment that protects the brain. Ketones mainly act as energy molecules. But exercise affects both energy AND the structure of the brain. This two-way approach may explain why moving is consistently linked more strongly to a strong brain than just diet.
How the Brain Can Use Different Fuel During Exercise
One of the brain’s great abilities is that it can use different fuel sources depending on what is available. Normally, glucose is the main energy source. But when you exercise, fast, or don’t have much energy, the brain can switch to using ketones, lactate, and even certain amino acids.
Lactate was often seen as just a waste product. But now we know it’s a good brain fuel during exercise. Muscles send lactate into the blood during aerobic activity. The brain easily takes it in to use for energy. This way of getting energy works better with regular exercise.
Also, regular exercise increases things like glucose transporters and other enzymes that help metabolism. This helps the brain take in and use available energy better—no matter what form it is in. This flexible energy plan helps the brain keep thinking well even when the usual metabolic supports (like ketones) are not easy to get.
Being flexible, not depending on just one thing, shows how an active brain adjusts in hard times.
What This Means for People With Liver Disease or Metabolic Problems
If you have liver disease, diabetes, metabolic syndrome, or changes in metabolism from aging, you might worry about how well your brain can work. These problems make it harder for the liver to make ketones. This puts the usual ways the brain gets energy for thinking at risk.
But the good thing about this research is the good news it brings: regular physical activity starts up completely different brain processes to improve thinking. This means even without reliable ketone production, your brain can still get better at memory, focus, and processing speed just by exercising.
This opens up new ways to help people
- Doctors can suggest exercise as a main treatment even for patients whose metabolism isn’t working well.
- People can protect their own thinking without big diet changes or supplements.
- People who help others with wellness can highlight movement as a basic part of clear thinking and mental strength.
No matter your metabolic condition, exercise helps your mental health.
Changing How We Talk About Ketone Hype for Brain Health
In the world of wellness, ketones have become a popular term. People see them as a fast fix for clear thinking, anti-aging, and top performance. From ketone drinks you can buy to more extreme keto diet methods, the idea has been that to think your best, you almost have to raise your ketones.
But this idea seems narrow now that we have these new findings. Ketones are important for protecting the brain—especially for helping control epilepsy and maybe managing Alzheimer’s symptoms. But they are not the only way to improve thinking.
What we should focus on more is physical activity. This is a behavior we can change. It has consistent, doable, and well-proven benefits for mental function. Linking your benefits only to ketone levels is like thinking a hybrid car runs only on its electric battery—you are ignoring how well the machine can adjust.
Instead of the next keto supplement, go for your next aerobic workout—your brain will like it better.
How This Could Help Prevent Alzheimer’s and Dementia
One of the most important things these results mean is for preventing diseases where brain cells break down, especially Alzheimer’s disease. A main sign of Alzheimer’s is that the brain doesn’t use glucose well. Earlier ideas suggested increasing ketones could be a way around this. But if patients cannot make ketones naturally—because of liver damage, aging, or insulin resistance—then that solution doesn’t work.
Here is where exercise comes in.
Many studies have shown that regular physical activity slows down the decline in thinking, improves mood, and increases connections between brain cells. This new study shows that exercise makes brain health stronger even when metabolism isn’t working perfectly. This removes a key limit for doctors planning ways to help people who are at risk.
This means that
- Fitness programs based on lifestyle could be as important as medicines for brain care.
- Family members and caregivers can offer easier, more available tools for prevention.
- More different groups of people, including those with metabolic problems, can take part in ways to keep their brains healthy.
How Much Exercise is Enough? (Simple Advice)
You don’t need to train like a top athlete to get the mental benefits from moving. In the mouse study, the amount of exercise for people would be like moderate aerobic exercise—like taking a fast walk, riding a bike easily, or joining a dance class.
For the best brain health, try for
- 30–60 minutes of moderate aerobic activity
- At least 3 to 5 days per week
- Add different kinds of activity, like cycling, swimming, or hiking
- Add strength training two times per week for more brain blood vessel benefits
What matters more than how hard you go is doing it regularly. Brain health doesn’t come from one long run. It builds workout by workout, week after week. Pick activities you like so it’s easy to stick with them.
Doing it often is the exercise secret for a strong brain.
Your Brain’s Best Friend Might Be a Jog, Not a Ketogenic Diet
Ketones are interesting and play an important role in how the brain gets energy. But saying they are the only way to get top thinking performance is too much. This new evidence makes us think differently. Exercise causes strong biological changes—like more BDNF, new mitochondria, and the ability to use different fuels—that happen no matter what your ketone level is.
So next time someone talks up the benefits of ketosis for brain health, you will have a more complete picture. The way to clear thinking, focus, and good memory may be just as well made by moving your body regularly and on purpose.
Moving your body may be the most reliable thing to improve your thinking that you can’t buy.
Want to take better care of your brain? Start with regular, moderate exercise. And if you want to learn more about mitochondria, brain flexibility, or how the brain changes, find more from The Neuro Times.
Citations
- López, A. M., et al. (2024). Even when ketogenesis was genetically disrupted in mice, eight weeks of treadmill exercise improved memory performance in object location and object recognition tasks. These mice showed similar memory outcomes to control mice with normal liver ketone production.
- Jensen, N. J., et al. (2020). Ketone bodies play a critical role in brain energy metabolism during fasting or prolonged exercise. Journal of Neurochemistry, 152(3), 313-330.
- Erickson, K. I., et al. (2011). Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences, 108(7), 3017–3022.
