MAR 31, 2022 9:00 AM PDT

Light Exposure While Sleeping is Linked to Cardiovascular Issues

WRITTEN BY: Savannah Logan

A new study published in the Proceedings of the National Academy of Sciences has shown that light exposure while sleeping impairs cardiometabolic function. The study included 20 healthy adults who were randomized to sleep in either a moderately lit room or a dimly lit room. After only one night in the moderately lit room, participants showed an increased nighttime heart rate, decreased heart rate variability, and increased insulin resistance.

Perhaps counterintuitively, increased heart rate variability, or the time between heartbeats, is linked to positive health outcomes and lower stress. In essence, higher heart rate variability is a measure of your body’s resilience and adaptability to change. Decreased heart rate variability, in combination with increased heart rate, indicates that the nervous systems of participants in the moderately lit rooms were more active than they should have been. This likely leads to less restful sleep, which could add up quickly for those who consistently sleep in moderately lit rooms.  

Insulin resistance occurs when muscle, fat, and liver cells don’t respond effectively to insulin. Insulin is a hormone that helps control the amount of glucose (sugar) in the bloodstream, so insulin resistance can lead to increased blood sugar. Over time, this can lead to type 2 diabetes and weight gain.

Light exposure at night is known to reduce sleep quality and has been implicated in several negative health outcomes. To avoid light exposure at night, be sure to close the blinds and avoid leaving lights on. Covering the light from alarm clocks may also be a good idea, and some sleep experts even recommend covering or removing clocks from the bedroom to help with insomnia. If outdoor light is unavoidable, sleep masks and blackout shades can help. One author of the study noted that if you can easily see around your bedroom at night, it is probably too light.

Sources: PNAS, Sleep Foundation, Cleveland Clinic, Clinical Advisor, Science Daily

About the Author
PhD in Biophysics
Savannah (she/her) is a scientific writer specializing in cardiology at Labroots. Her background is in medical writing with significant experience in obesity, oncology, and infectious diseases. She has conducted research in microbial biophysics, optics, and education. She received her Ph.D. from the University of Oregon.
You May Also Like
FEB 19, 2022
Health & Medicine
The Search for Genetic Links in Sudden Unexplained Child Deaths
FEB 19, 2022
The Search for Genetic Links in Sudden Unexplained Child Deaths
Sudden unexplained death in childhood (SUDC), similar to sudden infant death syndrome (SIDS), occurs when children betwe ...
MAR 08, 2022
Cardiology
Poor Sleep May Nearly Triple Heart Disease Risk
MAR 08, 2022
Poor Sleep May Nearly Triple Heart Disease Risk
Poor sleep has many negative consequences, including a serious impact on heart health.
MAY 19, 2022
Cardiology
Death from Heart Attacks More Common in US than Other High-Income Countries
MAY 19, 2022
Death from Heart Attacks More Common in US than Other High-Income Countries
The US has a high rate of heart attack mortality compared to other high-income countries.
MAY 24, 2022
Cardiology
Obesity in Pregnancy Increases Child's Risk of Heart Disease
MAY 24, 2022
Obesity in Pregnancy Increases Child's Risk of Heart Disease
Obesity and unhealthy diets cause gene expression changes that negatively impact the cardiac function of offspring.
JUL 21, 2022
Clinical & Molecular DX
Scientists Find a Potential Cause and Treatment for Shorter Life Span in Men
JUL 21, 2022
Scientists Find a Potential Cause and Treatment for Shorter Life Span in Men
Scientists are beginning to understand the significant impact of a process called hematopoietic mosaic loss of Y chromos ...
AUG 02, 2022
Technology
Coolants in Disposable e-Cigarettes Pose Significant Health Risks
AUG 02, 2022
Coolants in Disposable e-Cigarettes Pose Significant Health Risks
e-Cigarettes skyrocketed in popularity when they were first introduced, especially when flavored cartridge e-cigarettes ...
Loading Comments...