What factors affect the speed at which an action potential travels?

There are several factors affecting the rate and speed of an action potential:

1. Myelin sheath - This covers some of the nodes and acts as an electrical insulator where the action potential travels from one node of ranvier to the next by saltatory conduction. 

2. Diameter of the axon - the larger the diameter of an axon increases the rate and speed of conductance as there is less leakage of ions.

3. Temperature - The higher the temperature the faster the conductance. This is because enzymes work faster at a high temperature which control the sodium-potassium pump needed to create action potentials.