When babies don’t grow properly early in life, it can affect how their brains develop and work as they get older. Scientists wanted to know if intense exercise could help fix these brain problems. They studied mice that had growth problems as babies and gave some of them a tough exercise program while others stayed inactive. Surprisingly, even though the exercise made the mice healthier in other ways, it didn’t fix the brain changes caused by early growth problems. This suggests that early growth issues may have lasting effects on the brain that exercise alone can’t reverse, and doctors might need to find different ways to help.

The Quick Take

  • What they studied: Whether intense exercise training could improve brain function and growth in mice that had growth problems when they were babies.
  • Who participated: Laboratory mice that were either born with growth restrictions or born normally. Half of each group did intense exercise for 4 weeks, and half stayed inactive.
  • Key finding: Intense exercise improved the mice’s overall health and body weight, but it did not improve the brain proteins related to learning and memory in the mice that had early growth problems.
  • What it means for you: This research suggests that early-life growth problems may create lasting changes in the brain that can’t be fixed by exercise alone. If you or someone you know had growth problems as a baby, this doesn’t mean exercise isn’t helpful—it just means other treatments might also be needed to support brain health.

The Research Details

Scientists created two groups of mice: some that had growth problems when born (because their mothers didn’t eat enough protein) and some that grew normally. All mice were fed healthy food starting at 3 weeks old. At about 6 weeks old, half of each group started doing intense exercise on a treadmill 5 days a week for 4 weeks. The exercise involved running hard for 8 minutes, then slower for 2 minutes, repeated several times. The other half of the mice didn’t exercise. After the study ended, the scientists looked at the mice’s brains to measure special proteins that help the brain learn and remember.

This type of study is called an ‘animal model study.’ Scientists use mice to test ideas before trying them with people because mice brains work similarly to human brains in some ways. The researchers carefully controlled everything—what the mice ate, how much they exercised, and exactly when they measured the brain proteins.

The study was designed to test whether intense exercise could reverse brain changes caused by early growth problems. The researchers measured four different brain proteins that are known to be important for learning, memory, and brain flexibility.

Understanding whether exercise can fix brain problems caused by early growth issues is important because many children around the world experience growth problems. If exercise could help, it would be a simple and safe way to improve brain health. However, if exercise can’t fix these problems, doctors need to develop other treatments. This research helps scientists understand the limits of what exercise can do and guides them toward finding better solutions.

This study was published in a well-respected scientific journal focused on sports medicine and exercise science. The researchers used careful scientific methods to measure brain proteins and controlled the mice’s environment tightly. However, this is animal research, so the results may not work exactly the same way in humans. The study doesn’t tell us the exact number of mice used, which would help us understand how reliable the results are. The findings are surprising because previous research suggested exercise should help, so more research is needed to confirm these results.

What the Results Show

The main finding was unexpected: intense exercise did not improve the brain proteins in mice that had early growth problems. The mice with early growth problems had lower levels of important brain proteins (TrkB, Bdnf, and Gap-43) compared to mice that grew normally, even after exercise training.

However, the exercise did have some positive effects. Both groups of mice that exercised lost weight and became healthier in their bodies. This shows that the exercise program was intense enough to create physical changes, but these physical improvements didn’t translate into brain improvements for the growth-restricted mice.

The mice that grew normally showed a similar pattern—their brains didn’t show increased levels of the measured proteins after exercise, though they did get healthier overall. This suggests that the type of exercise used in this study may not be the best way to boost these particular brain proteins, or that early growth problems create brain changes that are very difficult to reverse.

The study revealed that early growth problems create lasting differences in brain chemistry. The growth-restricted mice had consistently lower levels of brain proteins related to learning and memory throughout the study, even after they were fed healthy food for weeks. This suggests that the damage from early growth problems may be permanent or very difficult to reverse. The fact that exercise improved physical health but not brain proteins suggests that different types of treatment might be needed to help the brain versus the body.

Previous research had shown that intense exercise increases a brain protein called BDNF (brain-derived neurotrophic factor) in healthy animals and people. Scientists expected this study would show the same effect in growth-restricted mice. However, this study found that growth-restricted mice didn’t show this response to exercise. This is an important finding because it shows that early growth problems may change how the brain responds to exercise, making it harder for exercise to help the brain in the way it normally does.

This study has several important limitations. First, it was done in mice, not humans, so we can’t be sure the results apply to people. Second, the study doesn’t tell us exactly how many mice were used, which makes it harder to know how confident we should be in the results. Third, the study only tested one type of exercise program, so other types of exercise might work better. Fourth, the study only measured brain proteins at one point in time (at the end), so we don’t know if the proteins might have changed at different times. Finally, the study doesn’t explain why exercise didn’t work as expected, so more research is needed to understand the reasons.

The Bottom Line

Based on this research, we cannot confidently recommend intense exercise as a treatment for brain problems caused by early growth restriction. However, this doesn’t mean exercise is bad—it still provides many health benefits for the body. If you or someone you know had growth problems as a baby and is concerned about brain health, talk to a doctor about what treatments might help. This research suggests that doctors may need to develop new approaches beyond just exercise to address brain changes from early growth problems.

This research is most relevant to doctors and scientists who work with children who had growth problems early in life. Parents of children with early growth restriction may find this helpful to understand that exercise alone might not fix brain-related issues, and other treatments might be needed. People interested in how early life experiences affect lifelong health should also find this interesting. This research is less directly relevant to people who grew normally as children.

This study doesn’t tell us about realistic timelines for humans because it was done in mice over just 4 weeks. In humans, brain changes from early growth problems likely develop over months or years, and any treatment would probably take months to show effects. If you’re considering treatments for brain health related to early growth problems, ask your doctor about realistic timelines for seeing improvements.

Want to Apply This Research?

  • If you’re interested in exercise and brain health, track your weekly exercise minutes and note any changes in memory, focus, or mood over 8-12 weeks. Record the type of exercise (intense intervals, moderate steady exercise, etc.) and how you feel afterward.
  • Start with a sustainable exercise routine that includes both intense intervals and moderate activity. While this study suggests intense exercise alone may not fix early brain problems, regular physical activity still supports overall brain health. Aim for 150 minutes of moderate activity or 75 minutes of intense activity per week.
  • Track exercise consistency, energy levels, sleep quality, and cognitive function (memory, focus) monthly. If you have concerns about brain health related to early growth problems, work with a healthcare provider to monitor progress and adjust your approach as needed. Consider combining exercise with other brain-healthy habits like good sleep, nutrition, and mental stimulation.

This research was conducted in mice and may not directly apply to humans. The findings suggest that intense exercise alone may not reverse brain changes caused by early growth problems, but this doesn’t mean exercise isn’t beneficial for overall health. If you or your child experienced growth problems early in life and have concerns about brain development or cognitive function, consult with a qualified healthcare provider for personalized medical advice. Do not use this information to replace professional medical diagnosis or treatment. Always speak with a doctor before starting any new exercise program, especially if you have health concerns.