We're entering the time of year when burnout strikes. Whether you're busy, tired or your motivation is just shot, we've all been there. That doesn't mean you have to stay there. While you can't control everything that happens to you, you can intentionally work toward increasing the chemicals in the brain that are associated with happiness.

Four main hormones trigger feelings of happiness. Understanding these chemicals and how they work can help you find ways to boost their production and give yourself the mood lift you've been looking for. 

To explain exactly how these "happiness" chemicals work, I spoke to Loretta Breuning, founder of the Inner Mammal Institute and author of Habits of a Happy Brain.

Happy chemicals: The secret to a happy brain 

Almost everything that makes you feel "happy" is linked to one of the four happiness hormones: dopamine, serotonin, endorphin and oxytocin. Here are some ways you can boost them naturally.

Dopamine

The hormone dopamine is associated with motivation and reward. It's why you feel gumption when you set an exciting or important goal, and why it feels good to reach that goal. On the flip side, if you have low dopamine (which experts say can occur with depression), it can explain feelings of low motivation or loss of interest in something you used to enjoy.

"Approaching a reward triggers dopamine. When a lion approaches a gazelle, her dopamine surges and the energy she needs for the hunt is released. Your ancestors released dopamine when they found a water hole," Breuning says. "The expectation of a reward triggers a good feeling in the mammal brain, and releases the energy you need to reach the reward." 

How to boost dopamine

Some not-so-healthy habits increase dopamine like drinking caffeine, eating sugar or taking certain recreational drugs. You can find ways to kick this hormone up without turning to potentially unhealthy or addictive substances. 

"Embrace a new goal and take small steps toward it every day. Your brain will reward you with dopamine each time you take a step. The repetition will build a new dopamine pathway until it's big enough to compete with the dopamine habit that you're better off without," Breuning says. 

You may already have goals set around your career, work or how much money you'd like to make. Don't forget personal goals. Committing to a rewarding hobby or sport can be just as gratifying as professional goals. Don't just set a few big goals that will take longer to complete -- also adopt shorter-term goals so you stay motivated.

"Set a short-run, long-run, and middle-term goal so you will always be approaching one when another is blocked. Focus on things you have control over and don't wait for others to set your goals for you," Breuning says.

Serotonin

Serotonin is a neurotransmitter that plays a role in mood, but it also helps regulate other functions in your body like digestion, sleep and bone health. When it comes to happiness and how you feel every day, serotonin is important for reducing depression and regulating anxiety.

How to boost serotonin

"Confidence triggers serotonin. Monkeys try to one-up each other because it stimulates their serotonin. People often do the same," Breuning says. You've probably never thought about confidence on a neurochemical level, but according to Breuning, if you don't prioritize confidence, your serotonin levels could take a hit. 

If you are trapped in a cycle of low self-esteem or have had others undermine your confidence, it can be hard to build it back up. It may sound strange, but don't ignore your need for respect and status. 

"You can develop your belief in your own worth. If you focus on your losses you will depress your serotonin, even if you're a rock star or a CEO. You can build the habit of focusing on your wins. Your serotonin will suffer if you don't," Breuning says. 

Besides focusing on what you've achieved in life, you can also build confidence in other ways. One way to do this is by working out or adopting a new exercise routine, which helps bolster your confidence when you stick to it over time. Something else you can try is finding ways to get out of your comfort zone each day. Every day that you challenge yourself to adapt to something new, even if it feels uncomfortable at first, you build more confidence. 

Oxytocin

Oxytocin is sometimes called the "love" hormone and is associated with how people bond and trust each other. Certain activities like kissing, hugging and having sex can trigger the release of oxytocin in the brain. 

It explains why you feel happy when you pet or cuddle with your pets. It's important in childbirth since oxytocin helps the mother's uterus contract to deliver the baby, and oxytocin plays a role in breastfeeding too. It also helps parents bond with a baby after birth.

How to boost oxytocin

You can boost oxytocin by being physically intimate with others. Besides the physical aspect, it's important to know that there's an emotional connection to how oxytocin is released.

"Social trust is what triggers oxytocin. If you hug someone you don't trust, it doesn't feel good. Trust comes first. You can build social trust by taking small positive steps toward people," Breuning says. 

You can reach out to a friend or contact you'd like to get to know better. Send someone a thank you note or a card just to tell them you're thinking about them. "Take a small step toward someone each day, and they may reciprocate months later, but if you keep doing it you will build trust networks," Breuning says. 

Endorphins

Endorphins are notoriously linked with exercise: It's the phenomenon that explains the runner's high or post-workout endorphin "rush." They function as "natural painkillers" that help minimize pain and maximize pleasure. This chemical experience can explain why a runner may be able to push through a race with an injury that they don't notice until it's over.

"In the state of nature, it helps an injured animal escape from a predator. It helped our ancestors run for help when injured. Endorphins evolved for survival, not for partying. If you were high on endorphins all the time, you would touch hot stoves and walk on broken legs," Breuning explains.

How to boost endorphins

Laughter is one way to boost endorphins naturally; so is eating dark chocolate, watching your favorite drama on Netflix, working out and meditating. 

Endorphins are released in response to pain, but that doesn't mean you should seek out ways to cause yourself harm (like by overexercising or pushing yourself beyond your limits) just to feel good. 

"Inflicting harm on yourself to stimulate endorphins is a bad survival strategy. Fortunately, there are better ways: laughing and stretching. Both of these jiggle your innards in irregular ways, causing moderate wear and tear and moderate endorphin flow," she says.