It’s a common belief that mental activities like studying or thinking hard can actually burn a significant number of calories. The idea is that when your brain is working hard, it requires extra energy, which translates into calories being burned. This claim has become popular among students and knowledge workers looking for ways to passively boost their calorie expenditure throughout the day. But is there any truth to the idea that you can “burn calories” just by studying? Let’s take a detailed look at the evidence.
Yes, mental activities like studying do burn some extra calories, but the effect is generally small. Most research finds that activities like reading, writing, and problem-solving burn only around 10-15% more calories than rest. For the average person, that’s just 10-30 calories per hour of studying. So while you can burn a few extra calories studying, it’s not a major calorie-burning activity in itself. The brain does use energy when active, but not a huge number of calories.
How Many Calories Does the Brain Use?
The brain is an energetic organ that relies on a constant supply of fuel in the form of glucose and oxygen from blood. It’s estimated that although the brain accounts for just 2% of body weight, it uses around 20% of the body’s metabolic energy when at rest. During intense mental work, the brain may use up to 25% more energy than when at rest. Just how many calories does this represent?
Calories Used at Rest
Research suggests the brain uses around 320 calories per day in an average adult at rest. So if you were to lay in bed motionless all day, your brain would burn through about 13 calories per hour. This varies based on brain size, age, and other factors.
Calories Used During Mental Work
During intense mental exertion, like taking a test or attending a lecture, the brain may use up to 15-25% more energy. That translates to around 15-30 extra calories burned per hour of studying for the average adult. The calories burned also depends on the type of mental activity, with more demanding tasks like math problems burning slightly more calories than passive study sessions.
Studies on Calories Burned Studying
A number of controlled studies have measured how many calories are actually burned during common studying and learning activities:
- One study found that doing math problems burned around 20% more calories than rest.
- Another study showed that simply reading a textbook burned 14% more calories.
- During a lecture, college students burned 10-15% more calories than watching TV.
- Completing memory tests has been found to burn 12% more calories.
Based on these and similar results, it’s estimated that a typical study session burns 10-30 calories per hour more than resting quietly. That’s not insignificant, but far less than more active tasks like walking or exercising.
Calories Burned by Task
|Calories Burned Per Hour
|Resting / watching TV
|Attending a lecture
|Completing math problems
As you can see, the difference studying makes is real but modest for most people. Studying burns 10-30 calories more per hour compared to complete rest.
Why the Brain Burns More Energy When Studying
The increase in energy use by the brain during study sessions is related to a few key factors:
- Active neurons require more energy: Large networks of neurons activate during intense thinking and studying. This requires more energy to power ion channels, neurotransmitters and action potentials.
- Cerebral blood flow increases: More oxygen is delivered to the brain via increased blood flow when focused and active. This allows the brain to metabolize more energy.
- Neurochemical production: Focus and learning lead to more synthesis of stimulating neurotransmitters like dopamine. Making these chemicals expends energy.
In essence, the brain ramps up its activity levels when engaged in intense cognition, which directly translates into higher calorie and energy use.
Tips to Burn More Calories While Studying
While studying doesn’t burn nearly as many calories as heavy exercise, there are some tips to maximize the amount of energy your brain uses while hitting the books:
- Study intensely and avoid distractions – Passively reading won’t burn many calories, but intensely focusing and engaging will ramp up brain energy use.
- Tackle challenging material – Working through complex concepts leads to greater neural activation. Choose demanding study topics to burn more calories.
- Switch topics frequently – Switching between math, reading, writing etc. recruits different brain networks, burning more energy.
- Work for longer study sessions – The calories burned accumulates over hours of focused study. Study for at least 2-3 hours at a time.
- Stay hydrated and fed – Having proper nutrients supports greater brain energy expenditure. Eat and drink during long study periods.
Making small adjustments like these can help burn slightly more calories through increased mental exertion.
Other Benefits of Studying and Mental Work
Beyond the modest amount of calories burned, regularly engaging in intense study and other mental activities provides other key benefits:
- Improves memory and cognition – Just like physical exercise, frequent mental exercise improves brain function by building new connections and capacity.
- Reduces cognitive decline – People who regularly challenge their mind have been shown to be less prone to age-related cognitive decline.
- Boosts productivity – Hours spent studying hard are an investment that often translates into greater career and academic success down the line.
- Creates positive mental stimulation – For many people, intensely focusing on learning new skills or information provides enjoyment and stimulation.
So while the calories burned from studying alone may be minimal, the long term cognitive and productivity benefits make it a worthwhile use of time for most students.
Limitations of Calculating “Calories Burned” from Studying
The concept of “calories burned” during mental work does have some limitations to consider:
- Estimates are rough – The true number of calories burned can vary considerably based on the individual, intensity, nutrition status and other factors.
- Hard to accurately quantify – Unlike physical exercise, it’s difficult to accurately measure variables like exertion level during mental tasks.
- Mental work has other effects – Studies show thinking and learning impacts things like mood, stress and focus that all influence calorie use.
- Long term adaptations – The brain can become more efficient at cognitive tasks over time, reducing the energy needed and calories burned.
So while we know studying does burn extra calories through increased brain activation, the actual number can be challenging to quantify accurately on an individual level. The estimates provided here are rough averages.
Based on the research, it’s clear that activities like intense studying do in fact increase the calories burned by the brain. However, for most people the effect is fairly small, in the range of just 10-30 extra calories burned per hour. While not negligible, this is modest compared to more strenuous physical and mental activities. The extra energy used by the brain during study sessions is mainly attributed to increased neural activation, blood flow, and neurochemical production. There are some techniques people can use to potentially maximize the amount of calories burned while hitting the books. But in general, the biggest benefits of studying come from the long term gains in cognition, memory, productivity and overall mental function. While the concept of “calories burned” studying is real, it shouldn’t be thought of as a major source of calorie expenditure for most individuals. The cognitive boosts are usually far more valuable.