Waiting 60–90 minutes after waking up to drink coffee can help your body's rhythms work in tandem with the coffee, rather than against them. Here are some reasons why:

• Cortisol levels - When you wake up, your body's cortisol levels naturally increase, which can help you feel alert. However, drinking coffee too soon can interfere with this process and make you feel more stressed and anxious. Waiting allows your cortisol levels to peak and start to drop, so when you do drink coffee, it won't diminish the effects of cortisol.

  
  

• Energy - Waiting gives your body time to use its own resources for energy before you consume caffeine. Some recommend starting the day with water and a balanced breakfast or snack instead.

  
  
  
  

• Circadian rhythm - Maintaining a healthy circadian rhythm is important for optimal sleep and wakefulness. Drinking coffee too soon can disrupt this rhythm.

  
  
  
  

• Afternoon slump - Waiting until later in the morning can help you avoid an afternoon slump and improve your sleep at night. It can also help extend the effects of caffeine into the early afternoon, which can counter any drop in alertness at that time.