We all cry for different reasons. For some of us, it takes a tragedy to set us off. For others, a scene from "The Notebook" is enough to bring on the bawling. But one thing is for sure: Crying is part of what makes us human. Although some animals do shed tears, humans are the only ones who cry for emotional reasons.
It's not only emotional triggers that start the waterworks, though. There are actually three different types of tears. First, there are the ones that sit in our eyes all the time for protection, called basal tears. Then, there are reflex tears that come in response to a physical irritation -- think onion-chopping. Finally, there are the tears that set us apart from other animals -- the emotional ones.
Whether it’s due to onions or a funeral, sometimes you find yourself tearing up more often than usual and you just don't know why. Here are five sneaky reasons you're crying all the time.
1. You're tired.
Babies aren't the only ones who cry when they're sleepy. Adults do it, too. You may suddenly find a cereal commercial bringing tears to your eyes. This abnormal blubbering could be a sign that you're not getting enough sleep. A study conducted by researchers at the University of Pennsylvania showed that regularly logging only 4.5 hours of sleep each night led to negative changes in mood, ranging from irritability to sadness.
To combat sleepy sniffling, make sure to get enough Zzs each night. While there's no magic number for how many hours each person is supposed to get, somewhere between seven and eight hours of sleep is usually a good place to start, according to the National Sleep Foundation.
2. You have stuff in your eyes.
Chopping onions often comes to mind when we think of reflex tears, which are tears produced to protect your eyes from irritants. Nerves in your cornea tell the brain stem that there's something bugging your eyes. The brain stem then sends hormones to your eyelids, which produce tears to help wash out whatever is irritating them. But it's not only onions that cause this reflex. Other irritants include smoke, dust or even a strong gust of wind. The fastest way to eliminate this type of tear is to prevent the irritant, whether that means wearing sunglasses on particularly breezy days or less onion-chopping.
3. You have two X chromosomes.
Women are biologically built to cry more often than men, The Wall Street Journal reports. Men's tear ducts are actually larger than women's, meaning that it takes less liquid to spill over a woman's eye than it does a man's. So when guys tear up, it's easier for them to blink the blubbering away, while women's tears are more likely to start streaming down their cheeks.
In addition, somewhere between 20 and 40 percent of women report experiencing premenstrual syndrome in the days before their menstrual cycle begins. In addition to bloating and headaches, crying spells are one of the most common symptoms of PMS, according to the Mayo Clinic.
But women's predisposition to tears doesn't all stem from the way they're made. It also has to do with social conditioning. Research published in the journal Cross-Culture Research looked at crying differences between genders across different countries, all of which had varying levels of wealth and freedom of expression. The gender divide between the amount of tears cried was most dramatic in wealthier, democratic and feminine countries.
4. You're stressed out.
While no one has done a study directly looking at crying and stress, higher levels of anxiety are connected to more waterworks, Lauren Bylsma, a postdoctoral scholar researching childhood depression at the University of Pittsburgh, tells The Huffington Post. "We do find that conflict situations tend to be a big elicitor of tears, and that is a form of interpersonal stress," says Bylsma. "Sometimes in these situations the crying can help facilitate a resolution to whatever the conflict was that caused the tearful reaction in the first place. So crying also has some interpersonal functions, including eliciting help or support from others."
But does crying actually help relieve some of that stress? Some people feel better after a good cry, while others don't, says Bylsma. Several factors come into play, including the situation in which it took place, the reaction of onlookers, mental health factors and even the reason for crying in the first place. "There is also some limited evidence that stress hormones may be secreted by the tears when crying in response to stress or negative emotions, compared to non-emotional tears," Bylsma says. "But other research needs to examine this further before we can make definitive conclusions."
5. You may be depressed.
Although with extreme levels of depression there is less crying and more emotional numbing, an increase in crying could be a sign of depression, Bylsma says. About 9 percent of Americans are affected by depression. Feeling sad or numb all the time, a loss of appetite or energy, and other symptoms are all signs of the mood disorder. Depression often gets worse if left untreated. If you suspect you may be depressed, contact your doctor as soon as possible to get the help you need.