Sleep timing and caffeine cutoff

Caffeine and Sleep Physiology

• Caffeine blocks adenosine receptors, delaying sleep pressure.
• Reduces slow-wave (deep) sleep and REM sleep quality.
• Can increase nighttime awakenings and reduce overall restfulness.

Half-Life and Sleep Disruption

• Average caffeine half-life: 3–6 hours in adults.
• In sensitive individuals or slow metabolizers, half-life can extend to 8+ hours.
• A late-afternoon cup may still leave stimulatory levels at bedtime.

Research Findings

• A study showed caffeine taken 6 hours before bedtime still reduced total sleep time by ~1 hour.
• Evening caffeine worsens sleep onset latency (time to fall asleep).
• Habitual use can mask sleep debt but does not eliminate long-term impairment.

Practical Cutoff Guidance

• General recommendation: Stop caffeine 6–8 hours before bedtime.
• Early risers: consider last cup by late morning.
• Slow metabolizers (CYP1A2 variants) may need even earlier cutoffs.
• Alternatives in afternoon/evening: decaf coffee, herbal teas, caffeine-free beverages.

Lifestyle Tips

• Track personal sleep quality with/without late-day coffee.
• Use lower doses (espresso over cold brew) if consuming later in day.
• Be mindful of hidden caffeine in sodas, energy drinks, chocolate.

Summary

Caffeine can significantly disrupt sleep onset, depth, and duration if consumed too late in the day. Most people should cut off caffeine 6–8 hours before bedtime to protect sleep quality, with earlier cutoffs for sensitive or slow-metabolizing individuals.

• Tags:
• Cold Brew
• Decaf Coffee