The disruption of circadian rhythms Technology creates artificial stimuli that alter the circadian rhythms of living beings, affecting us and our pets, as well as any nearby animal that happens to live close to civilization.
I will try to summarize the case here, but if anyone is interested, I suggest looking for complete sources.
Circadian rhythms are regulated by light, food intake, physical activity, socialization, and temperature. All these stimuli result from the natural cycles of day and night.
Think of any diurnal animal, e.g., a lion: it wakes up with sunlight; it hunts and eat, and does so during the day, not at night; it is exposed to the ambient temperature, which follows a characteristic pattern as everywhere on earth the day is warmer than the night. The lion suffers stress, but it's acute (e.g. when it's hunting, or fighting with another lion to defend its position).
If you compare natural life to our artificial world, it is easy to realize that there are thousands of ways our society deregulates these biorhythms. The difference between day and night disappears, and many times, they are even turned inside out.
Examples are artificial lights and screens, television at night, snacking before bedtime, nightclubs (which put together a lot of stimuli at the wrong time: socialization, noise, physical activity, calorie intake), going to the gym after sunset, having the air conditioner too cold at work but the ambient temperature at your home (so the temperature profile is the opposite of a natural one), chronic stress instead of acute stress during the daytime, etc. These problems result from conflict both of social convections and technology with our gens. To live in society we must accept artificial timetables, artificial light, etc. Also indirectly, so that if you want to do some exercise, work at office and obligations may only leave you time to do it in the evenings.
Because there are so many aggressors and most are unavoidable, the only way to deal with them is to try to minimize them. On the one hand, try to plan your life so that the evening is a time without stress, screens, television, physical activity, food, etc. Be with your family, but not socializing with outsiders. Create contrast so that in your daytime you include the opposite: try to work nearby a window, or at least receive bright artificial light; do some exercise, receive some sun on your skin early in the morning, socialize with others, have your stressful moments here (so if you have to do some job you don’t like, or discuss with something, favor doing so here!), etc. On the other hand, try to find alternatives to the factors you can’t control. At night, use bulbs with dim light and whose spectrum is as free as blue and green light as you can (so the bulb should be reddish). If the light from the street bothers you, use dark curtains. You can also use blue or green blocking glasses instead of changing the bulbs at home, although it seems like the exposure of skin to blue light is also damaging at night. Use traditional books instead of screens. Wake up with the light coming through the window (if you can sleep with it open, but if you have a street lamp nearby it is probably better to sleep with the curtains) or use an alarm clock based on light (the cheapest way to do so isn't to buy an actual alarm-clock, which are too expensive and not very customizable; so you better buy a programmable light bulb that simulates the sunrise in real-time). For the bulbs, it's funny that you can find guidelines to minimize damage to wildlife, but we seem to forget that we are animals too--and were once wild! So there is a certification called "wildlife lighting". Two of its requisites is that light sources must emit only a long spectrum (<560 nm, so they’ll be reddish with no blue or green), and they must be the lowest intensity possible for its purpose. If you find bulbs with this certification, they are good for humans to use at night too. For more references on how to make artificial light less damaging at night, you can check: (i) https://www.environment.gov.au/system/files/resources/2eb379de-931b-4547-8bcc-f96c73065f54/files/national-light-pollution-guidelines-wildlife.pdf (ii) https://myfwc.com/conservation/you-conserve/lighting/ (iii) https://myfwc.com/wildlifehabitats/wildlife/sea-turtle/lighting/ Another goal is to avoid flickering, which also has detrimental effects on our health. Bulbs usually flicker at 100 or 120 Hz. Your eyes can't see it, but a (slow) camera may be able. Depending on the bulb design and its controller, you can find bulbs with very low flicker or none. But they are difficult to be found, as most brands don’t use that claim.
Finally, one may wonder why to take so much trouble to mimic the natural cycles of day-night. The thing is that every cell, tissue, and organ in our body needs to keep time for the same reason that large societies need clocks: to be able to carry out functions that require synchronization. Circadian rhythms impact every aspect of health. If they are not appropriate, you will be poorly rested, your immune system will be weakened, you will have low energy and low mood, and you will have a much higher risk of developing psychological, metabolic, and all kinds of chronic diseases.