(Mira Miller/ Very Well Health) — Getting enough sunlight during the day is critical for good health. But when it’s time to wind down, bright light exposure can suppress melatonin production and even increase the risk of cancer.
Research has repeatedly shown that bright light exposure at night—especially blue light—increases the risk of prostate, colorectal, and particularly breast cancer.
“Bright light exposure at night can suppress the body’s production of melatonin, a hormone that regulates sleep and possesses anti-cancer properties, thereby potentially increasing the risk of breast cancer,” Yong Zhu, PhD, the assistant director of the Yale Cancer Center for Global Cancer Epidemiology, told Verywell.
The International Agency for Research on Cancer (IARC) classifies night shift work, which involves exposure to high levels of light at night, as a probable carcinogen.
A 2017 study found that long-term rotating night shift work was associated with a higher risk of breast cancer, particularly among women who performed shift work during young adulthood.4 Another analysis from 2018 concluded that night shift work increases the risk of breast cancer in pre-menopausal women, particularly those with high intensity and long duration of exposure.(…)