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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.