how many hours before bed should you stop taking caffeine

Caffeine should ideally be avoided within the 8 to 12 hours preceding bedtime to ensure that it doesn't disrupt the architecture and quality of sleep. Since the half-life of caffeine is such that it can affect sleep, even if you can fall asleep, the depth and restorativeness may be negatively impacted 1 2 3. Therefore, it is recommended to have your last caffeine intake no later than mid-afternoon, depending on your specific bedtime 1.

Your body temperature typically peaks in the afternoon, slowly declining toward nighttime. This follows the rise from the temperature minimum, which occurs 90 minutes to 2 hours before your average waking time, and reflects the circadian rhythm of body temperature 1. So if you usually wake up at 6:30 AM, your temperature minimum would be around 4:30 AM to 5:00 AM, and you would expect your temperature to peak several hours later in the afternoon.

The peak in body temperature occurs sometime between 4:00 PM and 6:00 PM, as detailed by Andrew Huberman. This is approximately 10 to 14 hours after the temperature minimum, which tends to be around 4:00 AM 1. The exact timing can vary from person to person, but this is a general pattern aligned with the circadian rhythm.