Dehydration and Hangovers
Dehydration might be the cause of your morning headaches. Although your body’s processing of liquid slows at night, you have still gone six or eight hours without consuming any water. As a result, your body is dehydrated when you wake up in the morning.
You may also have a hangover. You may not think that you consumed excessively the night before, but you may have accidentally consumed more alcohol than you thought (it’s easy to lose track when you drink, and if you’ve switched from your normal beer to a microbrew you might not realize how high the alcohol content is).