What is the 2 hour coffee rule?
Quick answer: the 2 hour coffee rule suggests waiting at least two hours after waking up before drinking your first cup of coffee. This guideline aligns with the body’s cortisol levels, aiming to optimize both the effects of caffeine and the body’s natural wakefulness cycle. According to emerging research in circadian biology and neuroscience, waiting about 90 minutes before having caffeine can improve focus, mood, and nighttime sleep quality. It’s not about giving up your morning brew — just about timing it to align with your body’s natural cortisol rhythm.The caffeine in coffee affects your levels of adenosine and melatonin, two key players in making you sleepy. Because of this, drinking coffee late at night likely isn’t a good idea. In fact, it may be beneficial to try to avoid consuming caffeine within 6 hours of bedtime.After waking, cortisol—a hormone that boosts alertness—peaks within 30–45 minutes. Drinking coffee during this peak can reduce caffeine’s effectiveness and increase tolerance. Waiting 90–120 minutes allows cortisol to decline and adenosine to build, making caffeine more impactful than coffee to keep you wake.