that is how i describe the jittery feeling. it feels like i haven't eaten in awhile or like i just finished lifting weights and the lactic acid in makes my body shakey. That's why i don't lift weights anymore.
this is JMO, but i think the jittery feeling comes from muscles tensing and then relaxing and then tensing again. i think it does release lactic acid in your system. and then when you don't eat enough, i think it makes it worse.