THE FIVE: Essential Lifestyle Principles For A Life In Sync
- Yoga: Asanas (Postures) + Pranayama (Breath)
- Meditation + Mindfulness
- Psychic Sovereignty (Our Relationship To Technology)
- Sleep Hygiene
- Outdoor Rituals
Caffeine consumption is a well-loved and almost ubiquitous morning ritual—one study concluded that 85% of all Americans over the age of 2 consume at least one caffeinated beverage every day. 
Caffeine rituals certainly have their benefits (we enjoy a nice cup of coffee or Ketobasis Matcha Latte as much as anyone). If caffeine is a part of your lifestyle, though, it’s essential to understand how it affects your sleep.
Unsurprisingly, caffeine and sleep are not a great match—research has shown that caffeine typically prolongs sleep latency, reduces sleep time and efficiency, and worsens perceived sleep quality. 
Nevertheless, by understanding more about caffeine’s effects and making a few informed lifestyle choices, you can enjoy high-quality sleep without having to give up your beloved caffeine rituals.
Caffeine Blocks Circadian Sleep Signals
The brain has a remarkable system in place for ensuring proper sleep: your circadian rhythm determines the timing of your sleep-wake cycles, and your sleep pressure system enforces these cycles by making you feel tired when it’s time to sleep.
The neurotransmitter adenosine plays a critical role in this process. It acts as a kind of timekeeper; the longer you stay awake, the more of it accumulates in the brain. Adenosine is an inhibitory neurotransmitter and can act as a central nervous system depressant, so its buildup in the brain leads to an increasing feeling of sleepiness (i.e. increased pressure to sleep). 
Caffeine functions as an adenosine receptor antagonist—it blocks signals sent by adenosine receptors, in other words—so it effectively tricks your brain into thinking it’s not tired. Because this signalling is a crucial step in the body’s sleep induction process, it’s much more difficult to sleep while caffeine is still in your system. The post-caffeine crash occurs because built up adenosine will bind to receptors all at once when caffeine is cleared from the system.
Caffeine Increases Heart Rate
Caffeine activates the nervous system and inhibits phosphodiesterase enzymes, which help keep your heart rate in check. As a result, caffeine is usually associated with increased heart rate, as well as a delay in your resting heart rate (RHR) reaching its lowest point. 
These cardiovascular effects aren’t an issue during the day, but they can disrupt your process of winding down for sleep. Even subtle deviations from your normal RHR make it more difficult for your body to relax into those critical "deep sleep" states. 
Tracking your heart rate and monitoring how caffeine affects it can be a useful practice for determining your ideal caffeine consumption schedule. If your RHR is higher than normal at bedtime, try moving your caffeine cutoff time to earlier in the day.
How To Use Caffeine Intelligently (i.e. Timing + Dosage)
1. Timing - As you’ve probably already figured out, minimizing caffeine’s impact on sleep is all about proper timing.
The effects of caffeine last longer than you might think, though. Even though most people feel the maximum effects of caffeine between 30-60 minutes after consumption, it actually has a half life of 5-7 hours.  This means that 7 hours after ingestion, up to half of that caffeine is still in your system!
Other factors can lead to caffeine being broken down even more slowly. For example, 50% of the population have a gene variant that slows down the metabolism of caffeine by the liver.
Being aware of how your body processes caffeine can help you determine an ideal caffeine ritual schedule that won’t negatively impact your sleep. For most of us, this will mean cutting out afternoon and evening caffeine consumption (or at minimum, drinking your afternoon caffeine dose as early as possible).
2. Dosage - So many people continue to drink caffeine well past the point of diminishing returns. That second and third cup of coffee in the day often has a minimal (if any...) benefit for your focus/mood/alertness, but has a massive negative impact on your sleep quality. And if there is a benefit, it's often psychological rather than metabolic (meaning decaf would work just as well).
It's a good practice to cultivate a sensitivity to when you've consumed the dose that yields the maximum improvements to focus/mood/alertness, and then stop drinking there. And for those subsequent cups of coffee/tea/whatever...experiment with decaf to see if you can get much of the psychological benefit without having to ingest the extra 100-200mg of caffeine that is guaranteed to wreck your sleep quality.
_________________________________________________________ https://www.tandfonline.com/doi/pdf/10.1080/10408398.2016.1247252  https://doi.org/10.1016/j.smrv.2016.01.006