Women who drank more than 4 cups of coffee per day, had a 20 per cent lower risk of becoming depressed. The reason being the caffeine, a natural stimulant which stimulates the central nervous system and increases dopamine levels  . An increase in dopamine levels removes the symptoms of depression and anxiety  . And due to this people are less likely to commit suicide .
As noted here, numerous studies have highlighted the potential health benefits of caffeine. Meanwhile, centuries of caffeine consumption and extensive study of the ingredient further reinforce its safety. In other words, the billions of people who routinely consume caffeine can continue to do so with confidence and the knowledge that the ingredient may even enhance health.
Don’t you know that drinking black coffee is powerful for your nervous system performance? It is able to stimulate the nervous system which gives command to break down fat during the metabolism process and convert them into energy. This is the reason why black coffee can improve our workout performance which is good for your effort to lose weight. In addition, black coffee will also activate the nervous system to release dopamine and serotonin, hormones which help you to feel happy and fights against depression.
I never fully understood how K-Cups worked until I got my own machine. Each little pod is basically a small packet of coffee grounds. The machine pokes a hole in the top and bottom of the packet that the water drips through, just like a mini version of a big coffee maker. The small serving size and ease of clean-up makes for the perfect cup with no hassle. We even take our machine camping sometimes!
The method of preparing these three black coffees, namely Black eye, Red eye and Dead eye, are similar except the proportion of espresso added in each. These 3 black coffees are prepared by adding shots of espresso with dripped coffee and do not contain sugar or milk. In “Black Eye Coffee” two shots of espresso are added with dripped coffee; in Red eye, a single shot of espresso is added with dripped coffee and in Dead eye coffee, three shots of espresso are added with dripped coffee.
Some health benefits of coffee come from the beverage's caffeine content and not necessarily from the coffee itself. For example, the review of studies published in Australian & New Zealand Journal of Psychiatry determined there was also a nonlinear association between caffeine and a lower risk of depression, in addition to the link with coffee itself. Caffeine, a stimulant, also has a beneficial effect on athletic performance, with research published in 2016 in the Journal of Sports Science determining that dosing with caffeine prior to physical activity increased "vigor" and decreased fatigue. To use this to your benefit before working out, drink a cup of black coffee about 30 to 45 minutes before you begin exercising.