How is Energy Used in the human body? 4 Important Ways

Energy is used in the human body in 4 different ways, like

  1. Mechanical energy
  2. Electrical energy
  3. Heat energy and
  4. Radiation energy.

Energy is critical for the body; without it, death occurs instantly.

This energy is always spent by the body, and hence, there is regular hunger for food.

But before you read further, you must know How food is converted to energy in the body.

Details on Energy Usage in the Body

1. Mechanical energy

This is the energy with which the body moves and performs physical activities.

It is derived from ATP (adenosine triphosphate) and expressed through the body’s muscles.

Mechanical Energy is used in physical activites.
A young, sporty man stretching his arms.

All the activities of limbs and other body parts come under mechanical energy.

2. Electrical energy (nerves and muscles)

This energy runs through the nerves of our body. It is generated and dissipated along the nerves.

Doctor checking for nerve conduction.
Nerve Conduction Velocity is a test of electrical signals through a nerve

It is meant for quick communication between body parts and functions.

It helps conduct signals with electric speed.

3. Heat energy.

This is energy that is formed due to metabolism.

It is essential for the functions of enzymes, maintaining body temperature, and other physiological activities.

Woman relaxing after heat exposure.
Woman sweating due to heat

It is derived from ATP through muscle activity.

4. Radiation energy.

This is the energy that dissipates into the surroundings of our body.

Have you ever noticed that you can sense someone behind you even without looking while standing in a queue?

It is due to this radiation energy.

These four types of energies are derived from food as ATP by the biological oxidation of carbohydrates in the presence of oxygen.

How is Energy Used in the human Body that we obtain from food

And also, heat energy is formed in the muscles to maintain body temperature.

Radiation energy is the one we feel as an aura around us. You can even notice someone when they stand very close to you due to this radiation energy.

How is Energy Used in the Human Body?

Physical exertion

This is how most of the body’s energy is spent in living animals and human beings.

This is done due to the intention to move, perform, or work. This may not be seen in plants, as they do not move.

The body’s energy is also consumed for muscle contractions and relaxation.

We see this during walking, running, lifting, jumping, talking, shouting, etc.

Further, body language also consumes energy.

So, you can notice that when you are hungry, your body language will be low and ineffective.

Mental exertion

This is the next way energy is used in higher animals, like humans.

A lot of energy is consumed for thinking, learning, and memorizing.

Hence, at least 20% of the blood pumped from the heart goes directly into the brain during the heartbeat.

This brain is a high-energy-demanding organ that requires more glucose and oxygen from the blood.

Besides, anxiety and other behavior-related functions need energy.

Hence, you can notice that eating more will reduce stress.

So the Body first tries to fill this energy need more than others.

Even animals do some brain and behavioral activity, but it is low, unlike humans.

Physiological functions

  • All the physiological functions in the body need energy.
  • These include heartbeat, blood flow, breath (inspiration & expiration), digestion, intestinal contractions, etc., which require constant energy.
  • These are involuntary in nature, without the intention of the animals.
  • But are always active and energy-demanding.
  • The body’s energy is mostly used due to smooth muscle contractions in the gut, blood vessels, and lungs.
  • The cardiac muscle in the heart is even more active, and high energy is demanding.

Also, blood vessels carry blood to the corners of the body and are brought back by veins by contractions and relaxations.

Body metabolic and synthetic reactions

  1. Most body cell reactions, like the formation of proteins (translation), multiplication of genes, and the formation of genes, demand energy.
  • Also, transporting salts and nutrients across the cell membrane and degrading toxic waste (metabolism) requires energy.
  • Further enzymes are the key factors involved in the above reactions.
  • These enzymes perform only at body temperature.

So, the body tries to maintain heat at a constant rate through heat generation.

The cyanide pill is so effective in causing death as it causes rapid energy failure by arresting the mitochondrial enzymes responsible for producing energy (ATP) in the body.

Energy wastage

  • The body energy formed is quite valuable, but still, it is lost.
  • Here, the energy is dissipated from the body in the form of heat.
  • The body tries to maintain a constant, fixed temperature to maintain its physiology.
  • This temperature is generated by burning calories in muscles.
  • During cold weather or atmospheric temperatures, the body loses heat.
  • So you can remember that you will feel more hungry during the winter and crave food.
  • Also, energy is lost when the material goes out of the body.
  • This we prominently see during breathing; hot air goes out, and fresh air comes in.
  • Also, heat is sometimes lost due to urination and bowel evacuation.

So, the energy formed is thus used up in four ways and lost in one way.

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