Jitters are what an overshoot feels like: shaking hands, a fast heartbeat, restlessness and a strange irritable focus. For most people it starts somewhere past 400 mg, and much lower if you rarely drink caffeine.
What is actually happening
Caffeine blocks the receptors that would normally tell you that you are tired, and pushes adrenaline up. Your body reads that as mild alarm, so you get the physical part of stress without anything to be stressed about.
What helps in the next hour
- Drink water. It will not flush the caffeine out, but dehydration makes every symptom sharper.
- Eat something. Food slows absorption of whatever is still in your stomach and steadies your blood sugar.
- Move gently. A ten minute walk burns off the adrenaline your body is sitting on.
- Breathe slowly. Longer out-breaths than in-breaths bring the heart rate down within minutes.
- Wait it out. The peak passes about an hour in, and the worst of it fades in three to four.
What does not help
Another coffee to level out, alcohol to take the edge off, or a cold shower. None of them clear caffeine any faster, and the first two make the evening worse.
If this keeps happening, the pattern is usually the same three days a week. Caffy shows you which days go over your line, and by how much.