Turns out, for a 50% chance of death via caffeine, you need to consume -
[Your Mass] *  mg of caffein.
So for a 75 kg person like me, it'll take about - (75 * 150) mg = 11,250 mg of caffeine ~ 75 cups of latte to put me at a 50% risk of dying.
That's a lot of coffee!
There's no way you could drink a cup of latte for every kilogram of mass you have, in a significantly short interval of time (or even in a day for that matter!).
So thankfully, you cant get a caffeine overdose via coffee.
How coffee keeps you up
Before breaking down how coffee works, it's important to know that a molecule called 'adenosine' binds to the receptor cells in our brains which slows down brain activity.
This is our body's way of telling us to slow down, or get some sleep. So the longer you are awake, the concentration of adenosine goes up and eventually you feel tired, fatigued and sleepy.
Right after you wake up, the concentration of adenosine goes down and you feel more active.
Caffeine present in coffee, has a strikingly similar structure to adenosine.
So once you grab that cup-a-joe, here's what happens in your body -
Caffeine travels to your brain via your bloodstream and starts blocking the receptor cells before adenosine could get in.
The receptor cells bond with caffeine due to it's structure being similar to adenosine.
This stops adenosine to calm you down and stimulates the production of adrenaline, which increases heart rate, blood flow and makes you feel active.
This also helps your brain absorb more dopamine, which makes you feel happy.
Since caffeine has a half life of about 6 hours, you start to feel half the affects dropping off by this time. And so, you are tempted to go for another mug.
Now as a long term side affect of consuming caffeine, your brain responds by creating more adenosine receptors. which makes you drink more coffee to feel the buzz!
So, is drinking coffee addictive?
Good news - caffeine does not technically meet the definition of an addictive drug like cocaine or heroine.
It does cause some physical dependence but the withdrawal symptoms are nothing more than a few hours or a day of headache compared to the activation of 'brain rewards' circuits which other drugs lead to.
Drinking coffee the right way!
Now that we know coffee is not so devilish, it's safe to go on a quest to learn about better drinking habits.
From what I learned, our body clock (called the circadian rhythm) has certain timing to release a hormone called 'cortisol' - the stress hormone.
When you drink coffee during the peak cortisol release hours, caffeine's effects are greatly diminished. In the long run, this makes your body more resistant to caffeine and you want to consume more.
The cortisol peaks thrice a day -
8 am - 9 am
12 noon - 1 pm
5:30 pm - 6:30 pm
So the best timing to drink your coffee?
9 am to 12 noon, and
1 pm to 5:30 pm.
Post 6:30 pm, it could affect your night sleep. And before 8am, it's okay as long as you drink it an hour after you wake up (for generally high cortisol levels to go down).
Coffee is world's favourite drink for a reason. Understanding how it affects your body gives you an option to regulate when and how much you drink to make it work best for you.