More sensitive to brighther light (night) after dim light exposure

  • I'd like to discuss the research paper about bright light being more disruptive after you've been in a dark room or without light outside.

    I want to learn more because I use very dim lights at night, topping out at around 10-15 watts or so. I find it very relaxing as I probably should, but what worries me is seeing a brighter light will be more disruptive than ... I guess if I had a brighter light on instead of dim lights. Do you have enough information and understanding about this effect to give any timing information, (such as how strong the effect might be for just a minute or so, vs 20 minutes etc) so I can understand this better?

    Thank you.

  • Yes, the system sensitizes in 1-2 hours of dim light history, and you can see up to double the magnitude of effect after it is sensitized. In this experiment they saw an additional 60% phase shift and melatonin suppression.

    The trouble is from a circadian perspective, these exposure histories have very different effects - so the brighter light exposure would already have been doing some phase shifting and melatonin suppression by the time the "bright" exposure was started. (The experiment is totally correct, but it's important to think about.)

    I think it is a good design to generally decrease light levels through the night.

    But, just as a thought experiment, if you had a broken and very bright light in your house that flashed for 10 minutes at random, should you avoid dim light conditions because that light was going to affect you more? No, I wouldn't - dim light at the right time is still good, and the composite effects of 90 lux at the eye all the time would have a bigger impact on a person than dim + occasional exposure.

    For another example, if you were working the night shift and needed to drive home - I need to think about this one. If you know the "bright light" pulse will be delivered at the same time every day, you might use more moderate levels in advance of it. Of course, you may just want to be alert driving home, and more light would be the best choice in this case regardless.

    It is a good reason to get a dimmer in your bathroom though.

  • @herf Thanks, that really helps. So, bright light will still have it's normal effect, along with this "extra effect" after dim light, so you still say dim light before that, will be better if the times aren't predictable. I'm glad I won't think too much into this effect now, but I'm glad it's on your research page.

    I'm good on the dim bathroom light, I have two I can choose from, and one gets extremely hand burning hot (I have to turn it into the socket each time) using 20 watts, and the other no where near that level of heat using 24.5 watts. I like the dimmer more orange looking light, but wow it hurts! It's more orange, the other is a gold yellow and I don't like it as much.

Log in to reply