Stock Market · Risk Management & Psychology

Sleep, screen time, and decision quality

Trading is a decision-making sport. Every decision you make is a function of your physical state. Sleep, hydration, stress, screen time. Most traders ignore this entirely. They optimise their strategy but trade hungover, exhausted, and over-caffeinated.

Sleep deprivation = drunk trading

Studies show that 17 hours of sustained wakefulness causes cognitive impairment equivalent to a 0.05% blood alcohol level. After 24 hours awake, you're at 0.10%. Legally drunk in most countries.

Trading on 5 hours of sleep is trading impaired. You take worse setups, miss stop losses, and overreact emotionally.

> Your edge is your discipline. Your discipline is your nervous system. Your nervous system runs on sleep.

Screen time and decision fatigue

After 4 hours of continuous chart-watching, decision quality degrades sharply. You start seeing setups that aren't there. You break rules you wouldn't break in the first hour.

Professional traders limit screen time:

• 2-3 hours of focused analysis
• Hard breaks every 50-60 minutes
• Walk away when not in active positions

The physical checklist

Before every trading session:

• Slept 7+ hours? Yes / No
• Eaten recent, balanced meal? Yes / No
• Hydrated (water, not coffee)? Yes / No
• Free from significant stress/distraction? Yes / No

If 2 or more are 'No'. Reduce position size by 50% or skip trading entirely.

Caffeine

Moderate caffeine improves focus. Excessive caffeine (4+ cups) increases anxiety, which biases you toward overtrading and panic exits. Stay below 2-3 cups before market hours.

Tired traderexpensive trader

Rested traderdisciplined trader

Takeaway. Trading on 5 hours of sleep is cognitively similar to trading drunk. Limit screen time to prevent decision fatigue. Run a pre-session physical checklist, if multiple items fail, reduce size or don't trade.