Feeling tired due to insufficient sleep? A cup of joe answers that. One health benefit of coffee is that it makes you feel alert and energized as well.
The caffeine in coffee which acts as a stimulant will help you stay alerted and focused, aside from giving you the extra boost you need. It helps you keep going when you're lower in stamina.
So don't take your coffee for granted. It might be all that you need in your most haggard days.