My body is strong and my mind is calm.

Calm is not measured by whether you get alarmed. Everybody gets alarmed. It is measured by how long it takes to come back down.

Run for a bus and your heart climbs the same as anyone's; the difference between the fit and the unfit shows up in the ninety seconds afterwards. Minds appear to work the same way. The bad email still lands. The question is whether the rest of the afternoon survives it.

Recovery rate is trainable, which is the useful part — not by becoming harder, but by giving the system more practice at coming back.