Can light affect sleep, digestion and mental health?

Exposure to light is essential for the body to carry on the bodily functions. From knowing when to wake up, to when to eat, the light informs the body of the processes, exposure to light also helps in regulating blood pressure, body temperature and the chemical reactions in the body. Also read | From better sleep to enhanced mood: 6 amazing health benefits of morning sunlight

Resetting the circadian rhythm:

According to an article published in The Conversation, light helps in setting the internal clock of the body, also known as the circadian rhythm. It is a network of genes and proteins that help in regulating each other. This loop has a rhythm of 24 hours that helps in maintaining the bodily functions properly.

The central clock of the body is present in the hypothalamus region of the brain, and each cell of the body consists of its individual internal clock. These clocks work together to adapt to the daily cycle of light and dark.

However, the internal clock is not precise, and every morning, it needs to be restarted. Hence, the exposure to light helps in resetting the clock for the whole day. Also read | Exposure to artificial light at night is associated with risk of diabetes: Study

Effect of light on sleep:

The body produces melatonin, a hormone that helps us to fall asleep. When there is light outside, the body stops making this hormone. Closer to bedtime, it produces the hormone which can help us fall asleep. Sleep is also partially controlled by the genes that are part of the internal clock. These genes influence our sleeping patterns.

When the body is exposed to light at night, especially when we should be sleeping, can have negative implications on our health. It can disrupt the heart rate, affect sugar metabolism and even lead to psychiatric disorders such as depression, anxiety and bipolar disorder. In worst cases, it can increase the risk of premature death. Also read | Light exposure during sleep linked to blood pressure, diabetes, and obesity in older adults: Study

Light’s effect on gut:

Digestion follows a circadian rhythm. Muscles in the colon that help in movement of the waste are more active during the day. The gut’s circadian rhythm is influenced by its own clock and the body’s internal clock. It also depends on our meal timings.