Human body energy consumption

human physical body consumption.
while you are resting or sitting, you are still active and consuming considerable amounts of energy, and not like ‘not doing anything’.

Here are some AI (ChatGPT4o) made figures based on what there is:

How are these values calculated?

Energy expenditure is typically measured in kilocalories (kcal) and is calculated based on metabolic equivalents (METs), which represent the energy cost of physical activities as multiples of resting metabolic rate (RMR).

1. Resting Metabolic Rate (RMR): This is the amount of energy expended while at rest, usually estimated at around 1 kcal per kilogram per hour. For a 70 kg person, this would be about 70 kcal per hour while resting or doing minimal activities like sleeping.
2. MET Values: Each physical activity has an associated MET value. The MET value indicates how many times more energy is used during the activity compared to resting. For example, sleeping has a MET of about 0.9, sitting while working might have a MET of 1.5-2.0, and running can range from 7-10 METs.
3. Formulas:Calories Burned (kcal)=MET×weight in kg×duration in hours\text{Calories Burned (kcal)} = \text{MET} \times \text{weight in kg} \times \text{duration in hours}Calories Burned (kcal)=MET×weight in kg×duration in hoursResearchers calculate MET values through studies that track oxygen consumption during various activities. The more oxygen consumed, the more energy the body is using.

For specific activities, MET values have been established through clinical and physiological studies using methods like indirect calorimetry, where oxygen and carbon dioxide levels are measured to determine energy expenditure. ​

Breakdown:

1. Calories Burned (kcal): This is the end result we’re calculating for different activities.
2. MET Values: Represent the intensity of activities relative to rest, based on measured oxygen consumption.
3. Resting Metabolic Rate (RMR): The base energy expenditure (around 1 kcal/kg/hour), which serves as a starting point for calculating energy use in more intense activities.
4. Activity Oxygen Consumption: Experimental measurements of oxygen used during activities.
5. CO2 and O2 Levels: These are measured during respiration to determine how much energy the body is using.
6. Respiratory Exchange Ratio (RER): The ratio of carbon dioxide exhaled to oxygen consumed, used to calculate energy expenditure.
7. Calorimetry (Indirect): A method used in experiments to measure oxygen consumption and carbon dioxide production, allowing us to calculate energy expenditure.
8. 1 kcal/kg/hour: The standard base value for energy used at rest, known through experimental measurements.