Most people spend most of their time indoors, where artificial and natural light are combined. Artificial light has brought many opportunities to humanity, but it has also created some challenges for the body, which has evolved over thousands of years to respond naturally to sunlight during the day and darkness at night. This response is called the circadian rhythm or cycle, and is a 24-hour biological process that is common to almost all living things. Circadian rhythms are primarily influenced by light, although temperature and other stimuli also play a role.

If we spend most of our time indoors with artificial light, how can we ensure proper circadian rhythms? How can we use artificial lighting to support healthy circadian rhythms and a healthier lifestyle? Experts recommend creating conditions that mimic natural circadian light cycles. In the morning and afternoon, it is recommended to use more intense lighting to stimulate the body so that it is active and alert. In the evening, the light should be more subdued to promote relaxation and preparation for sleep.
Failure to follow these guidelines can result in disruption of circadian rhythms, which can cause sleep problems, lead to decreased energy during the day, and trigger other health problems.

A study conducted by the University of Toronto found that exposure to bright light increases the initial emotional response to a stimulus, and the effect can be either positive or negative.
Color temperature also has a significant impact on a person’s psychophysiological state. It is measured in Kelvin (K), where higher values indicate more intense and colder light. The terms “warm” and “cold” in this context describe the spectral characteristics of light, not its physical temperature. Warm light helps create a comfortable and relaxing environment, which creates a feeling of coziness and calm. Cold light, on the contrary, stimulates psychophysiological processes, increasing the level of wakefulness and concentration, which has a positive effect on cognitive functions and productivity.

Blue light reduces the level of melatonin, which is associated with sleep, making a person feel more alert. That is why it is not recommended to actively use mobile phones, computers, and watch TV before going to bed. These screens actively emit blue light, which interferes with falling asleep and can make sleep worse. However, it can be useful in other situations when the brain needs to be active and concentration high.
Warm yellow shades correspond to dawn or dusk, when a person is relaxed and not engaged in active daytime activities. Subdued warm light is optimally used in cafes and restaurants, bedrooms or other recreation areas.

Experts recommend making the most of natural light during the day, before going to sleep avoid cold shades and bright light, and in the evening give preference to warm yellowish shades. These simple tips can help you get your circadian rhythms back on track and help you recover, which can improve your well-being.