Sleep debt and coffee: the scalper's reaction time problem
Posted: Sat Oct 31, 2026 8:26 am
Scalping is one of the few trading styles where a half-second matters. Entry on a break of a level, exit on a failed retest, cancel on a news spike: all of it relies on noticing and clicking fast, and on not clicking when nothing is there. Tired traders do both badly. They are slower to notice, and they are more likely to react to something imaginary.
Coffee gets used as the patch. Reasonable in moderation, but a few points are worth testing rather than assuming. A big dose right before the open can bring jitter that shows up as fast, premature entries. Heavy afternoon caffeine can wreck the next night, which then wrecks the next morning, and the loop continues.
An easy experiment uses the existing journal. Add two columns: hours slept the previous night (rough guess is fine) and caffeine before session (none, one, two or more). After thirty or forty sessions compare average adherence to rules and net pips across the groups. Treat it as personal data, not a universal rule, and keep a skeptical eye on small samples.
If short-sleep days are clearly worse, the cheapest edge available is a rule: reduced size or no trading after a bad night.
Does your journal show a gap between rested and short-sleep sessions, and how large?
Coffee gets used as the patch. Reasonable in moderation, but a few points are worth testing rather than assuming. A big dose right before the open can bring jitter that shows up as fast, premature entries. Heavy afternoon caffeine can wreck the next night, which then wrecks the next morning, and the loop continues.
An easy experiment uses the existing journal. Add two columns: hours slept the previous night (rough guess is fine) and caffeine before session (none, one, two or more). After thirty or forty sessions compare average adherence to rules and net pips across the groups. Treat it as personal data, not a universal rule, and keep a skeptical eye on small samples.
If short-sleep days are clearly worse, the cheapest edge available is a rule: reduced size or no trading after a bad night.
Does your journal show a gap between rested and short-sleep sessions, and how large?