There is a ton of advice out there about how to strengthen your productivity, things like eating more vegetables to making more lists. Everyone claims to have the answers. But knowing what will really work takes more than just reading; it takes scientific inquiry, and proven studies.

I’ve put together this list of scientifically proven methods of boosting your productivity for those of you who want the facts, and just the facts. Utilize these methods in confidence, knowing you’re giving your body and mind what it needs to do your best work.

1. Work in natural light.

According to a study done in the neuroscience program at Northwestern University, there is a strong relationship between workplace daylight exposure and office workers' sleep, activity and quality of life.

According to the study, employees who worked in natural light slept on average 46 more minutes per night, slept more soundly and efficiently and reported higher quality of life scores than those who did not. Windowless workers had lower scores in measurements of physical problems and vitality than those who worked near daylight. They also had poorer outcomes in measures of overall sleep quality, sleep disturbances, and daytime dysfunction.

It’s well documented that a lack of natural light can disrupt they body's circadian rhythms, which can cause abnormal sleep patterns and also seasonal affective disorder, causing depression and lethargy, among other symptoms. All of the ways lack of light affects the body can greatly reduce your productivity and energy.

If you don’t work in an office that has windows, you can buy a natural light lamp that simulates natural light or find a new job where you can see the light.

Related: It's Time to Check In on These 5 Healthy Habits You Resolved to Keep

2. Work for 1.5 hours at a time.

Working in chunks of time instead of working for hours at a singular task has been proven to stimulate the brain making you more productive in the long run.

Research has shown that our brains get very sleepy in the mornings, almost every 90 minutes. So you can work more efficiently when you break your time into a ratio of 90:20 -- 90 minutes working before taking a 20-minute break. This allows you to get into what’s called a “flow state” when creativity is running at it’s optimum, and then rest your brain when it’s tired so you’re fresh for the next 90 minutes.

Related: 7 Essential Habits of a Healthy Entrepreneur

3. Get happy.

Though most people think success will create happiness, it turns out that very much the opposite is true. A leading researcher in happiness, Sonja Lyubomirksy, studies the correlation between happiness and productivity in her book, "The How of Happiness."

What she concluded was happiness has many positive outcomes that no one could predict -- outcomes beyond joy, love and contentment. When we’re happy, we experience more energy, higher engagement with work, better relationships, higher self-esteem and stronger mental and physical health.

In sum, creating your own happiness translates to a better life, which translates to higher productivity. The happier and healthier you are, the more you can do.

Related: 7 Healthy Habits That Maximize Your Productivity Every Day

4. Take a nap.

You may think naps are only for the very young and the very aged, but science has proven that naps are incredibly good for productivity. Here’s a short list of all science-backed proof that naps are the answer:

  • Naps keep you from burning out. David K. Randall writes in his book "Dreamland" that research subjects who napped showed greater emotional resilience, improved cognitive function and much more.
  • A Harvard researcher says that napping makes people more effective problem solvers. His research has shown that napping helps people “separate important information from extraneous details,” especially when taken midday to help get over afternoon fatigue.
  • NASA research shows that a short, 26-minute nap enhances performance by 34 percent and overall alertness by 54 percent.

Your productivity can change for the better; you have control over it. There are many tips and tricks available to you. But don’t take my word for it. Try these scientifically backed ideas and see if they work for you.