Just this past Tuesday, you were on fire! You got two projects finished before noon, conducted a short working lunch, and put in another five solid hours of productive work in the afternoon—with none of that post-lunch lag. You hit the gym on your way home, cooked healthy meals for the week and even did your dishes and laundry.

But on Wednesday, you weren’t the same person. You had a hard time getting started. Shopping discounts in your inbox and your nosy office mate distracted you. You couldn’t really get into a zone until 11 am, and by the time the day was done, you hadn’t accomplished much. Still, you felt drained. You went home, watched a few sitcoms and DVR, ignored your mother’s voice mail, and called it a night.

Your motivation ebbs and flows. You may have thought about it as just one of those inexplicable things, but science has uncovered the source of motivation. It’s an inner part of the brain known as the nucleus accumbens. Neurotransmitters, like little messengers, send chemical signals to other areas of your body, like your legs, arms, and hands. One of these signals is dopamine, which releases from one brain neuron, floats between empty spaces known as synapses and bumps against various receptors, before passing information to the next neuron.

Here’s where it gets interesting. When we get a surplus of dopamine in the nucleus accumbens, our brains trigger feedback for predicting rewards. In other words, our brains recognize something important is about to happen, and the dopamine goes to work. This chemical is what motivates us to overcome the tendency to procrastinate and be productive at work. It also motivates us to seek pleasure and avoid pain outside of work.

Researchers have found that highly productive people normally have higher levels of dopamine in the reward and motivation portions of the brain than do “slackers.” Fortunately, there are ways for all of us to get that dopamine flowing, and to have more productive days as a result.

Here are five ways to get yourself back into that zone you were in on Tuesday:

Recognize and Fight Sources of Resistance

There are three internal sources of resistance, or negative thinking patterns, that we must battle before we can accomplish anything:

1. “I can’t do this.”
2. “I don’t feel right about this.”
3. “I have to do this, but I don’t want to do this.”

These thinking patterns are not necessarily rooted in any truths. In other words, that vague feeling you experience as “I can’t do this,” has no bearing on your actual abilities. To combat this, think of previous instances when you have accomplished the same, or a similar task. Similarly, fight the feelings of “not feeling right about this” or “not wanting to do this” by recognizing that you have the power to reverse them. Focus on the rewards of successfully accomplishing your goals to get yourself in a state of mind to overcome these sources of resistance.

Get Happy

Psychology Today reports that there is evidence that people with extraverted, or uninhibited personality types tend to have higher levels of dopamine than people with introverted personalities. This may explain why many gregarious people are successful. This idea of getting happy first, before getting motivated is actually a reversal of the normal dopamine process (if you want to get a hit of dopamine, set a goal and achieve it). Since happiness also triggers the dopamine response, and it can be easier to generate, listen to music you love, talk to someone who makes you laugh, or eat your favorite fruit to get that happy feeling. Once the dopamine kicks in, get to work!

If you are the type of person who experiences prolonged bouts of unhappiness, it’s important to recognize that it is much harder to pull yourself out of a funk than it is to maintain happiness. Keep yourself out of this “danger zone” by routinely doing things that elevate your happiness (and dopamine levels, as well as other “happy” brain chemicals like oxytocin and endorphin). Avoid the critical “self-talk” that is highly associated with prolonged bouts of unhappiness. Do daily affirmations if that’s your style. Remember, you’re good enough, you’re smart enough, and doggone it, people like you. So listen to light background music while you’re writing reports and dance when you’re collating them!

Reduce the Feeling of Pressure

Maintaining daily to-do lists is a hallmark of organizational ability, but it can actually prevent some people from being productive. If you have struggled periodically with motivation in spite of being organized with to-do lists, consider that your lists may be a source of pressure. Long to-do lists can seem insurmountable, triggering the feelings of “I can’t do this” and “I have to do this, but I don’t want to do this.”

Consider cutting your to-do lists in half. If you have been paralyzed into inaction on days when your list has ten items or more, then take on your tasks incrementally. List three at a time, focus on one task at a time (known as single-tasking), get them done, and then put together another list.

Another way to reduce the feeling of pressure is to work collaboratively, or with a partner, when possible. If you find yourself under continuous pressure, consider doing what it takes—from talking with your boss to getting a new job—to find a way to share more of your responsibilities with others. You may also find more happiness in the collaborative process than in working solo, which triggers dopamine and raises your level of motivation, while reducing the feeling of pressure.

Changing your diet is another way to increase motivation and productivity that deserves its own post, and we’ve done just that. The more we understand how our brains and body work, the more we can address the root causes of our struggles and successes.