Have you ever felt completely worn out after a long day at school, even though you were just sitting and listening? It seems strange, right? How can learning be so exhausting? Let’s dive into why this happens.
Our bodies need energy to function, and we get this energy from the food we eat. Interestingly, about 30% of the calories we consume are used to maintain our muscles. But here’s the surprising part: even though our brain only makes up about 2% of our body weight, it uses a whopping 20% of our energy!
Most of this energy is used when brain cells, or neurons, send signals to each other. This process requires a lot of glucose, which is a type of sugar that comes from the food we eat. When we think hard, like during a tough test, our neurons need even more glucose and oxygen, which can lower the glucose levels in our blood.
Research has shown that when we engage in challenging mental tasks, our brains consume more glucose. A study published in the journal Physiology & Behavior found that after intense mental activity, there was less glucose in the bloodstream. This suggests that our brains are working hard and using up energy.
Another study in Human Factors: The Journal of the Human Factors and Ergonomics Society discovered that people feel more tired when they use both their minds and bodies compared to just physical activity. This is because the prefrontal cortex, a part of the brain involved in thinking and decision-making, shows increased activity and lower oxygen levels after combined tasks.
Since our brains use glucose for energy, you might wonder if eating sugary foods can help us think better. A review in the European Journal of Pharmacology found that glucose can indeed improve memory, but it depends on how much you consume and the person.
While it’s clear that mental tasks make our brains work harder, the question remains: do they actually make us tired? The answer isn’t straightforward. A small study in Psychosomatic Medicine found that people who did memory and attention tests burned 200 more calories than those who were just relaxing. However, it might not be just the mental effort causing fatigue.
Some scientists, like Claude Messier from the University of Ottawa, suggest that stress might play a role. Stress can make us feel tired and even lead to stress eating. Additionally, Matt Lieberman points out that high carbon dioxide levels in classrooms might slow down our thinking, adding to the feeling of exhaustion.
So, while learning and thinking hard can make us feel tired, it’s a combination of factors like energy use, stress, and even the classroom environment that contribute to this feeling. Understanding how our brains and bodies work can help us find ways to stay energized and focused during our studies.
Conduct a simple experiment to understand how your body uses energy. Track your food intake and physical activity for a day. Then, research how many calories are used by different activities, including mental tasks. Compare your findings with the article’s information about energy use in the brain and muscles.
Take part in a class activity where you engage in a challenging mental task for 20 minutes, followed by a short break with a small snack. Discuss how you feel before and after the snack, and relate it to the article’s discussion on glucose and brain performance.
In groups, create a short skit that demonstrates how the brain uses energy during learning. Include characters like neurons, glucose, and oxygen. Perform your skit for the class to illustrate the concepts of energy consumption and mental fatigue.
Keep a journal for a week, noting your stress levels, mental tasks, and feelings of fatigue. At the end of the week, analyze your entries to see if there’s a pattern. Share your findings with the class and discuss how stress might contribute to mental fatigue, as mentioned in the article.
Work in teams to assess your classroom environment. Measure factors like noise levels, lighting, and air quality. Discuss how these might affect your concentration and energy levels, connecting your observations to the article’s points about classroom conditions and mental fatigue.
Here’s a sanitized version of the provided YouTube transcript:
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After I took the SAT, I was so exhausted I wanted to sleep for days, but I just sat there for hours. How can sitting there and thinking wear you out?
Hey Brainiacs, Julia here for DNews. Have you ever been really tired after spending all day sitting around at school? How can you be so exhausted from literally just sitting all day? Why is learning so tiring?
Let’s start with the body’s energy usage. About 30% of the calories you consume go to maintaining your current muscle mass. While our brain only makes up 2% of your body weight, it uses up 20% of the energy you take in. One study published in the Proceedings of the National Academy of Sciences found that two-thirds of the energy the brain uses goes to the firing of cells. The remaining third is primarily for brain maintenance.
So where does that energy come from? Most of the energy the brain consumes is in the form of glucose from the foods we eat. When neurons fire, they require extra oxygen and glucose from nearby capillaries. Scientists believe that when performing a difficult mental task, neurons consume more glucose, leading to lower glucose levels in the bloodstream after tasks like a tiring test. Some studies support this idea.
Another study published in the journal Physiology & Behavior found that there was less blood glucose in the bloodstream, which researchers linked to neurons firing at a high rate. A more recent study published in Human Factors: The Journal of the Human Factors and Ergonomics Society found that people feel more exhausted when engaging both physical and mental faculties compared to just working out. The researchers noted strong activity in the prefrontal cortex and lower blood oxygen levels in that area after combined physical and mental tasks compared to just physical work.
Following this line of thought, consuming foods high in glucose should improve performance. A review published in the European Journal of Pharmacology found that glucose can enhance memory, but its effectiveness depends on the dose and the individual.
So, there is something about mental tasks that makes our brains work a little harder and use up more glucose. But does it actually make us tired? The results are mixed. One small study published in the journal Psychosomatic Medicine found that people who completed memorization and attention tests consumed 200 more calories than those who were just relaxing. However, it might be more than just mental exertion.
One scientist, Claude Messier from the University of Ottawa, suggests that it could be related to stress, as students might be stress eating. So while test-taking might be draining your energy, perhaps it’s also the classroom environment. Matt Lieberman explains how carbon dioxide levels in classrooms might contribute to slower cognitive function.
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This version removes informal language and maintains a more neutral tone while preserving the original content’s meaning.
Learning – The process of acquiring new knowledge or skills through study, experience, or teaching. – Students use learning techniques to understand complex biology concepts.
Energy – The ability to do work or cause change, often produced by chemical reactions in living organisms. – Plants convert sunlight into energy through the process of photosynthesis.
Glucose – A simple sugar that is an important energy source in living organisms and a component of many carbohydrates. – After eating, glucose levels in the blood rise, providing energy to cells.
Neurons – Specialized cells in the nervous system that transmit information through electrical and chemical signals. – Neurons in the brain communicate with each other to process information and control behavior.
Fatigue – A state of physical or mental weariness resulting from exertion or stress. – After a long day of studying, students often experience mental fatigue.
Stress – A physical, mental, or emotional factor that causes bodily or mental tension. – Stress can affect the body’s ability to fight off illness and maintain health.
Memory – The ability to store, retain, and recall information and experiences. – Memory plays a crucial role in learning and retaining new information.
Brain – The organ in the head of humans and other animals that controls thought, memory, emotion, and activity. – The brain processes information from the senses and coordinates responses.
Oxygen – A gas that is essential for the survival of most living organisms as it is used in cellular respiration to produce energy. – Oxygen is transported by the blood to cells where it is used to release energy from food.
Environment – The surrounding conditions in which an organism lives, including air, water, and other living things. – The environment can greatly influence the growth and development of organisms.
