Full body spasms can be caused by things such as muscle overuse and muscle fatigue, dehydration, and electrolyte abnormalities.
In rare cases the full body spasms could be caused by other things that are more serious and should be checked out by a doctor.
If the full body spasms happen too often or seem to get worse you should go to urgent care, the emergency room or see a doctor about the full body spasms just to be safe.
I sometimes will get full body spasms a few times per month and sometimes I go months without the full body spasms and in my case it's nothing serious but if it continues too often or gets worse then see a doctor about it.