The Science of How Temperature and Lighting Impact Our Productivity

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Recently I sat down with Brendan Baker, one of the smartest people I’ve come across here in Silicon Valley. Clearly his brainpower exceeds mine by far and Brendan started explaining about a few things that I somehow always deemed true, but could never quite back up with great arguments or put my finger on:

“Your environment has a huge impact on how productive you are. That means the temperature in your room, the colour of your walls and the noise happening around you. There are lots of great academic papers on this, I’ll send them to you.”

Right then, after chatting with Brendan, we went away to make a lot of changes in the Buffer office. We rearranged furniture, bought new lights, heaters and more. I knew that the insights would lead to me making a lot of changes to my environment.

Turning this all into a blogpost with the most interesting aspects seemed only natural to me. So without further ado, here are the insights on how we can adjust our environment for better lighting and temperature to be more productive:

Natural lighting vs. artificial lighting: How our bodies and brains react differently

One of the most striking discoveries I’ve recently had was the difference between daylight and artificial light. Of course, I could only talk about this from my own experience without having any research to back it up.

So in an incredibly interesting recent study scientist Mirjam Muench tried to find out about exactly that. They compared two groups of people, one being exposed to daylight, the other to artificial light over the course of several work days. Here is the outcome:

“Compared to the afternoon, people who had DL (Daylight) were significantly more alert at the beginning of the evening, and subjects who were exposed to AL (Artificial light) were significantly sleepier at the end of the evening.”

On top of “sleepiness”, which most of us could probably deal with is the fact that our cortisol levels drop significantly under artificial or poor lighting conditions. That means that we’ll be more stressed, and have less ability to stabilize our energy levels. Here is how a normal cortisol level flow should look like:

 

So, being exposed to dim light as well as too much artificial light makes both sleepy and also more stressed in the long run. I believe that’s one of the most powerful things to remember. Similar to the science about sleep, paying attention to these rhythms can transform your productivity for the better, not just give you a slight advantage.

 

Why are cold working environments so harmful for our productivity?

The last thing anyone thinks of when trying to get more done every day is to turn up your thermostat. And yet, that might just be the answer. If I think back, being in a cold environment is definitely one of the memories I remember myself the least productive.

And an awesome study from Cornell examined exactly that, coming to a frightening conclusion. They tested different office temperatures at a large Florida insurance company and this is what they found:

“When temperatures were low (68 degrees or 20 degrees Celsius) employees made 44% more mistakes than at optimal room temperature (77 degrees or 25 degrees Celsius).”

Now, the problem isn’t just that if you are cold you feel uncomfortable, the study points out. The problem is that you are distracted. If you are feeling cold, you are using a substantial amount of your energy to, well, keep warm.

A lot less of your energy goes towards concentration, inspiration and focus. And yet, that’s not all.

 

Warm environments don’t just make us more productive – they also make us happier

A warmer environment doesn’t just make us more productive, it also makes us genuinely happier:

“People were asked to rate the efficacy of heating pads or ice packs and then answer questions about their employer or a hypothetical company. Those who got their hands warm expressed higher job satisfaction and greater willingness to buy from and work at the made-up companies.”

The reason is quite obvious in hindsight. Our brain has difficulty in differentiating physical sensations with psychological ones. This becomes even more clear when considering Bargh’s research of our brain after cold and warm encounters:

“The warmed subjects were also more likely than the cold ones to offer to a friend the prizes they received for participation, suggesting a possible overlap between the neural centers of trust and physical comfort.”

This is extremely interesting I thought. Our brain really doesn’t see a difference between any physical warmth and psychological warmth. It definitely made me turn up the heat slightly, just as I was writing this. On top of just turning up the heat though, what can we do to take advantage of these findings?

3 best ways to control your environment for more natural light and warmth

 With all this evidence about how more natural light and better room temperature can help us be more productive, it seems that most of this isn’t quite in our reach to change. If we are working in a large office, how can we just change the whole room to a spot where more natural light reaches us? And yet, there are fortunately still a great amount of things we can do to take advantage:

  • Wake up before the sun rises: Muench’s research shows that even just getting a few extra hours in natural daylight can help our cortisol levels to be more naturally adjusted. We often forget that we wake up a few hours after sunrise. If you wake up at 8am in the summer, that’s 2-3 hours of daylight that you don’t let your body consume. Try switching it up and wake up just before the sun rises so you can grab more of the precious daylight.
  • Bring your own moveable heater: A lot of the time, even if you have the ability to change the thermostat in your office, chances are that the warmth doesn’t get evenly distributed across the room. Bringing your own, small moveable heater lets you erase the problem once and for all. In fact, having a small heater at the Buffer office made a big difference as some people sit closer to the central heater than others.
  • Focus on lensed-indirect light: Of course our first choice should be optimizing our home and office for natural lighting. In case that’s not possible, trying to get away from direct light and focusing on lensed-indirect light instead can make a big difference for your productivity and alertness. It means a bright, almost daylight-like lighting environment, that still doesn’t strain your eyes with direct light. Here is the difference in pictures from a Cornell study:

 

Quick last fact: A long hot bathe helps us become a warmer and more welcoming person

As a quick last fact, that I found incredibly interesting when researching for this article was this:

“People who take long, hot showers or baths may do so to ward off feelings of loneliness or social isolation.” John Bargh, Yale University

The reason is very interesting. We can substitute social warmth, that we might be lacking on a given day, with physical warmth, meaning a hot shower. Our brain sees little difference between the two, says John Bargh in a most amazing study at Yale.

Over to you now. How is the lighting and temperature situation in your office or home? Have you made any adjustments in the past that helped boost your productivity levels? I’d love to hear your findings on this, especially as I’ve started to experiment a lot more with this at home and at the Buffer offices.

Photo credit:  mjp*
Idea credit: Brendan Baker

 

  • garden

    It would be interesting to compare the effects of different types of lighting. The spectrum of Incandescent light, for example, is closest to the “natural” black body radiation of the sun. Are there corresponding health benefits to using incandescent over fluorescent light? Is this topic a taboo because of green trends?

  • http://www.qualitylogoproducts.com/blog Mandy Kilinskis

    I find the part about temperature to be extremely interesting. I have no scientific facts to back this up, but I always feel less productive when it’s too warm in the office. I get drowsy and and very lethargic and thus, not as productive. Is it possible that there’s a Goldilocks “just right” temperature for productivity?

    • http://twitter.com/alexcliff0rd Alex Clifford

      When it gets too warm you might get dehydrated which could lead to you feeling sleepy.

    • mcshady

      Me too. They did the study in Florida. Try making it 77 in an office north of Maryland and people will start sweating and dropping like flies.

      • Jeff

        I live/work in Florida – and no way is 77 optimal (way too warm to be comfortable working in an office) – because if the room is 77 degrees, the temperature is all I can think about instead of tasks at hand..

    • Guest

      Yep, I am exactly the same. Warm means sleepy, lethargic and less productive. Nothing to do with dehydration either, I basically monitor my pee for that and drink plenty of water. Maybe the study involved the sort of geriatrics who constantly complain it’s too cold and wear five cardigans. They should try studying people from naturally colder climates, as this assumes we all feel cold at 25 degrees and that none of us prefer feeling cold to feeling warm. An incorrect assumption.

    • guest

      I totally agree, for me, my body tends to generate a lot more heat than people around me, so I always have to have the temperature a few notches below room temp – otherwise, I get really sleepy or extremely irritated. Dehydration doesn’t seem to be the problem, even when I’m well hydrated and not sweating it’s still there. But, that’s just me, most people I know are generally more comfortable at higher temperatures than me. Nonetheless, the article gives great insight.

    • Kees C. Bakker

      25 degrees Celsius is way too high for a Dutch office. We keep it at 21. I think temperature is very personal. I perform better at 19 degrees and a sweater on… keeps the head cool. I guess is also depends on where you grew up?

    • DK

      Wow, what a great post. I’ve been quite sensitive to all of these environmentals for as long as I can remember. I wanted to respond to Mandy by saying that in most circumstances, due to a lack of sophistication on the part of HVAC controllers, “warmth” us usually achieved with lack of air circulation. Basically, if you want to set the thermostat to 77, that means you get zero FRESH AIR until people’s body heat warms up the room to that threshold. Then once it’s reached, you get a minute of recycled air coming from somewhere else in the building (but not fresh air from the outside). Perhaps Buffer can dig up a research study to prove this, but I firmly believe that people are getting sleepy because they’re literally suffocating and lack oxygen. It’s unfortunate that in most offices, heat is being mistakenly associated with sweating and sleepiness. Just think of how comfortable most people are OUTSIDE in a 77 degree weather… It hardly feels hot. By turning down the thermostat we get better ventilation since the a/c kicks in more frequently, but as Leo’s post aptly stated, it forces a sub-optimal temperature for most people to function.

  • http://www.colinwinter.com/ Colin Winter

    Minor correction: “On top of “sleepiness”, which most of us could probably deal with is the fact that our cortisol levels drop significantly under artificial or poor lighting conditions. That means that we’ll be more stressed, and have less ability to stabilize our energy levels.” — I think it meant to say “cortisol levels DON’T drop significantly under artificial/poor lighting”. Everything else made sense and it’s an important article for night owls like myself. I’d just add, cortisol levels dropping throughout day/sunlight is why bodybuilders lift in the afternoon. Exercise in general helps the body limit cortisol too. Here’s a supporting quote from livestrong article http://www.livestrong.com/article/article/86687-exercise-cortisol-levels/#ixzz2Kv3tTdp1

    “Cortisol increases available fuels by stimulating gluconeogenesis (the production of new glucose) in the liver, increasing storage of glycogen (the form in which the body stores glucose, or sugar) and by inhibiting the action of insulin, preventing glucose uptake into the muscle and increasing blood glucose. Additionally, cortisol increases protein breakdown in the muscle and fat in the adipose tissue; both processes deplete stored energy and release fuel into the bloodstream for quick use. …. The more training you do, the better your body will become at dealing with physical stresses and decrease the need to release cortisol. This effect is not limited to exercise; people who are regularly active show a decreased cortisol response to an emotional crisis when compared to sedentary controls.”

  • AverageJoe

    I’m also curious about the “Goldilocks” temp Mandy’s asking about.

    I work from home and find it interesting that on especially isolated days I’d sometimes take two showers a day….just had an urge in the middle of the afternoon. It makes perfectly logical sense after reading this that I only feel like the 2nd shower when I’m working on reports and not when I’m recording the podcast or working on phone/email/texting projects with others.

  • http://twitter.com/CavemanKLAUS Klaus Bravenboer

    Awesome article Leo. You’ll also want to check out Flux http://stereopsis.com/flux/ it adjusts the colour of your screen to match time of day, I can recommend.

  • Guest

    Leo,

    This is arguably one of the best blog posts I’ve ever read. I’ve always wondered about the effects of environment on focus, creativity, and concentration. The takeaways are super actionable. In fact as I write this I’m realizing my feet are really cold. Time to turn up the temperature.

    Keep ‘em coming!

  • Ramu Tremblay

    Leo,

    This is arguably one of the best blog posts I’ve ever read. I’ve always wondered about the effects of environment on focus, creativity, and concentration. The takeaways are super actionable. In fact as I write this I’m realizing my feet are really cold. Time to turn up the temperature.

    Keep ‘em coming!

  • http://www.cometton.com/ Tom Conte

    Leo,

    Great post, I found it very informational and will look to accomplish this type of setting in my own office one day.

    Question – in your research, did you come across research discussing how color of a room affects our productivity?

  • Gordon

    LED Lighting changes everything!

  • Shea

    Nice article. Been friends with Baker for about 10 years now – definitely a smart guy. My insight on “productivity: is simple. Silence. Pure silence. Where you can cut out everything around you. For 4-6 hours flat. This does not just increase “productivity” but, more importantly, drives insight and creativity. Without that space and time, true innovation does not happen.

    • Brittany

      I entirely agree Shea. While most people listen to music to avoid the silence, I’ve found I work wonderfully with no noise. I have a white noise from the hvac in the lab at work and it drives me nuts. Haha. I find myself unconsciously pausing from my work to listen to it. (The cold temperature and yellow lighting dont help much either) :/ Setting is crucial.

  • http://twitter.com/Still29 Jeff Warner

    One thing to consider in offices that don’t have access to natural light is “daylight” bulbs – standard fluorescent tubes with a temperature rating of 5000 Kelvin, as opposed to the more standard temps of 4100K (warm white) and/or 3500K (cool white).

    • Sam

      you have it a little backwards Jeff, the lower Kelvin temperatures are the warmer colors and the higher temperatures are the cooler colors….. 4100K is the color of the moon and the best color for visibility. The true answer is to get away from ALL fluorescent lighting and use Full-Spectrum LED Lighting.

  • http://www.latersbaby.net/ Crissy and Mags

    No wonder I”m always complaining about being cold at work!

  • http://www.facebook.com/hachevi Heriberto Vizcarra

    How serendipitous. Today I went on a long diatribe with an acquaintance on how companies save on energy cost with those fluorescent lamps but lose way more since that poor, unnatural lighting reduces productivity and employee health significantly. I need to go deep into that screen-indirect lighting.

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  • Kitotam

    Populations are so important in studies. Maybe in this study what is affecting “sleepiness” is not the temperature, but the artificial inducement of temperature. Maybe there’s something about machine processing of air to make it colder or warmer that changes how it affects the body. A colder environment in Florida has to involve more air passed through a machine rather than outdoor air. Likewise, a warm office in mid-winter Michigan is an office filled with machined air.

  • http://www.enmast.com/ Devan Perine

    Wow, LOVE this post, Leo. So great to see the stats and actual research.

    Work environment really affects me, though I could never really figure out why. My last office I worked in had terrible fluorescent lighting, and it was either as cold as the north pole or a sauna, and it was miserable. The offices were this ugly off white and there was no color in the office at all. I hated coming to the office — I feed off my environment and the office sucked the life out of me. We never got much natural lighting either. I’m now in an office that has tons of natural light and color. And I love coming to the office to work. It’s enjoyable, comfortable and energizing.

    I had a friend who turned down a job (mostly because of the position was not super ideal), but also because the office was terrible — stale with a massive room of cubicles in a room with no windows. It would be a terrible environment to work in and couldn’t deal with living half her life there. I would’ve done the same.

  • Jen

    Actually, high cortisol levels indicate stress, not the opposite.

  • http://www.andydesoto.com/ Andy DeSoto

    I hope you didn’t spend too much company money on your changes! Some of these effect sizes are awfully small. For example, Slide 26 on that Florida mistakes-with-temperature study doesn’t show much of a performance improvement as a function of temperature.

    And some of the science you mention is under serious debate by other academics. You would be very hard-pressed to replicate Bargh’s work (i.e., the Yale shower one) according to many psychologists. Take a look at this post for some more info: http://blog.dansimons.com/2014/01/replication-retraction-and.html

    Thanks for taking about behavioral science on the blog, though!

  • Teario

    I’ve definitely noticed an increase in my productivity since I started working from my bath outside in the garden.

  • Sairam

    LEED certification for buildings takes into consideration whether the building is sufficiently lighted by natural sunlight or artificial? Microsoft, Google and Wells Fargo buildings are leed certified ..

  • http://www.redbearded.com/ Cody

    Great article. I currently work from home most days so trying to get my office right has been a challenge. This has some pretty great info. The only thing I have a hard time with is 77 being optimal. I would be sweating something bad if I let it get that hot.

  • Kai

    As far as I am concerned, our brain will work productively with the temperature at 17 degrees celsius.

  • Keith

    The manager asked us as afternoon workers to shut all lights off as we moved from room to room. The building was mostly darkened after the sun set. I told the foreman to tell the manager to basically to f… o. I was going to book off sick and apply for workers compensation for depression. That protocol evaporated for all of us very quickly. Take care of your health because no one cares.

  • Sara V

    What about extreme warmth like 85-95 degree F in a classroom? What does the study say about that? These are rooms without air conditioners so we have no control over the temperatures.

  • John Smith

    So, if warm environments make us more productive, then how come countries with an overall cold environment, like Norway or the Netherlands, are so rich, while countries with a warm environment, like Africa, are so poor? My personal experience with this is that in a cold environment I work more, because I can’t go to the beach for example. In a warm environment I work less, because I feel like doing other stuff and working is more exhausting. This might just be because when I go on vacation I usually go to a place with a warm environment.

    • JRV

      I believe there’s a difference between warm and hot when mentioning Africa.

  • Jr.

    This makes total sense! Sometimes when im making music in my room, i have little blocks when i cant think of anything, and i have just realised its night time, grey or cold outside when i have problems with productivity! ill keep that in mind!

  • John

    NASA used to keep the Space Shuttle internal temperature at 72degrees F believing this to be the perfect working/living temperature.

  • Bono

    I think over heat is even worst than working in a cold working environments.
    I feel I cannot think while sitting next to the opening window and fans but 30 degrees outside at the same time….

  • G2

    “Optimal room temperature is 25C.” My body’s right!

    I easily get cold and noticed that I couldn’t focus when the temperature’s low.

    At home, my parents would tell me not to use the aircon if I’m just gonna set the thermostat to 25C. (I live in a tropical country and it’s really hot outside the house/office.) But 25C feels just right!

  • Kurt Larson

    And sound.

  • Laurence

    explains why I’m so not productive in my new job, I’m freezing under the AC vent!

    • http://blog.bufferapp.com Kevan

      Oh no! I think I’ve been in the same spot before, too! Hopefully a new desk opens up. :)

  • deshy

    Bit late to the discussion but I found the piece on lighting confusing. ” our cortisol levels drop significantly under artificial or poor lighting conditions. That means that we’ll be more stressed, and have less ability to stabilize our energy levels. ”

    Cortisol is a “stress hormone” and released in response to stress to provide ‘energy’ for the body. If unnatural light reduces cortisol I am not sure how this causes stress? I can understand how the body may not be able to respond (…less ability to stabilize…) to stress with lower cortisol but cause it seems a bit of a jump.