Sleeping in light damages the heart and increases insulin resistance

There are two types of people, those who can sleep with some light in the room and those who need total darkness to fall asleep. Now, a Northwestern University study sheds light on why it’s best to lower the blinds at bedtime, finding that even a small amount of ambient light in the bedroom could impair cardiovascular function during sleep, as well as increase insulin resistance to The next morning.

The research, published in the journal PNAS, analyzed the heart rate and insulin resistance of a group of 20 adults, half of whom slept in moderate light in their room and the other half in a dimly lit room. There is already evidence indicating that exposure to light during the day is capable of increasing heart rate, as it activates the sympathetic nervous system, speeding up the heart and putting the body on alert to face any situation that may arise during the day.

“The results of this study demonstrate that a single night’s exposure to moderate room lighting during sleep can affect glucose and cardiovascular regulation, which are risk factors for heart disease, diabetes, and metabolic syndrome.” Dr. Phyllis Zee, lead author of the study.

Light activates the autonomic nervous system

Therefore, the body does not rest well when there is light in the room, because, although it is asleep, when there is light the autonomic nervous system is activated. This is not natural, because when we sleep the heart rate and other cardiovascular parameters decrease and increase during the day.

The researchers also found evidence that people who slept in moderate light had higher insulin resistance the next morning. This health problem occurs when cells in muscle, fat, and living cells don’t respond properly to insulin, so they don’t have the ability to use blood glucose for energy. In order to compensate for this, the pancreas begins to produce more insulin and over time, the blood sugar level is increased.

“The brain detects it and acts like someone whose sleep is light and fragmented. Sleep physiology isn’t resting like it’s supposed to.”

The participants declared that they were not aware of the biological changes in their bodies during the night, however, Dr. Daniela Grimaldi, co-author of the research, has stated that “the brain detects it and acts like that of someone who is a light sleeper. and fragmented. Sleep physiology isn’t resting like it’s supposed to.” To avoid this, Zee has released some tips such as:

• Do not turn on lights: if they are required for safety, for example, in the case of the elderly, it is best to have a dim light and to be close to the ground.

• The importance of color: Red, orange or amber colored lights are less stimulating to the brain. Put aside those that are blue or white, they are the ones that most disturb sleep.

• Options if you can’t control the light: there are spaces where you can’t control the light, for example in hotels that don’t have blinds or blackout curtains, in these cases, Dr. Zee recommends masks.

Light is still an environmental problem and although it may not seem like it, it is also a form of pollution. Therefore, “these findings are particularly important for those who live in modern societies where exposure to indoor and outdoor nightlight is increasingly widespread,” Zee concludes.