Awesome question. The nervous system is so cool!

Neurons are some speedy guys. That’s why when we pick up a pencil, it seems as if we immediately know what the pencil feels like. What's really happening inside our bodies is a little more complex. The instant we pick up that pencil, a group of neurons in our fingers are activated, and fire, super-fast, through our spinal cord all the way up to our brain. How fast, you ask? Try around 75 meters per second fast! If you were driving in a car, that would be more than 150 miles per hour. Imagine that! But it can get even a little more complex than that.

Only TOUCH neurons will fire around 75 meters every second. Other types of neurons, like pain neurons, travel much slower, around 1 meter per second. That's like a car moving 2 miles per hour. Beep beep! So to sum up, it depends on the type of neuron.

Thanks for the great question.
Neurons transmit an electrochemical signal called the action potential. These signals travel down a part of the neuron called the axon, which is like a wire that carries the signal to other nerve cells. On average a nerve cell sends a signal at about 50 meters per second, which is over 100 miles an hour! This means that when you step on something sharp it does take some time for that signal to go from the nerves in your foot to your brain, although not very much time. In fact in taller people it takes longer for a signal to go from one area to another than in shorter people, but the difference is too fast to tell outside of a laboratory.

Depending on a number of factors, signals can be sent even faster. One important factor is how myelinated the axon is. Myelin is a fatty substance that acts as an electrical insulator, increasing the speed at which the signal is sent. A highly myelinated nerve cell can send a signal at up to 120 meters per second, or nearly 270 miles per hour, quite a bit faster than an airplane taking off! These quick speeds are the basis for everything the nervous system does, from making sense of what your eyes see to deciding what you're going to have for lunch.

Neurons transmit their signals from one part of the body to another through long nerve fibers. Depending on the job of the fiber, the speed can change a lot. For instance, some of the nerve fibers that come from your brain and tell your legs to move can travel as fast as 250 miles per hour. For a signal traveling this fast, it takes about 20 milliseconds to travel. However, some signals are much slower like the signals that tell you are being tickled and travel around 1 mile per hour. For this signal it can take a second or more for you to fully feel it.

Different nerve fibers send signals faster or slower based on how thick they are, with nerves that send signals faster being thickened. Also fast nerve fibers also have a protective jacket on them called “myelin” which also makes the signal move faster. Keep in mind that the fastest nerve signals are still about 2.5 million times slower than electricity. So nerve signals have electrical parts to them, but are not purely electrical.

The nervous system is made up of many different types of neurons that all play different roles. You have neurons that transmit commands to your muscles, that respond to touch, pressure, or cold, that respond to pain, and more!

Each neuron has its own speed it transmits impulses at. Muscle command neurons have one of the fastest speeds (80-120 m/s) which makes sense because during running or other physical activities we often need to make quick adjustments to how we are running and what are body is doing. At that speed it would take under 9/1000 (.009 or nine thousandths) of a second for a signal to get from your brain to your hand.

Other neuron speeds vary from .05-2.0 m/s for pain/warmth to 3-30 m/s for touch and pressure. If you have ever grabbed something hot on accident and it has taken a second to realize it, that was caused by the slower neuron speed of pain/warmth neurons.

The speed of the neuron likely depends on the importance of a quick response. If a muscle command neuron worked at the slower speed of a pain neuron (which happens for some medical conditions), it would be very difficult to walk or keep balance. On the other hand, the slow rate of pain neurons doesn’t result in any major loss of function, so those neurons can be slower.

Overall, each neuron type has a different speed they operate at in order for the nervous system to function.