For hospitalized adults with depression, exposure to bright light each day lowers the average level of cortisol in the body over a 24-hour period by about 1.37 ng/mL compared to dim light, suggesting a more regular daily rhythm of this hormone.

Pro

Against

Evidence from Studies

Supporting (1)

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The effect of bright light therapy on glycemic control and cortisol rhythmicity in depression: a randomized controlled trial.

Randomized Controlled Trial

Human

2026

Contradicting (0)

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No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

The effect of bright light therapy on glycemic control and cortisol rhythmicity in depression: a randomized controlled trial.

Score: 67

DOI: 10.3389/fpsyt.2026.1743465

Similar Assertions

For hospitalized adults with depression, exposure to bright light each day lowers the daily fluctuation in cortisol levels by about 1.27 ng/mL compared to exposure to dim light.

93%

In hospitalized adults with depression undergoing bright light therapy, decreases in blood sugar levels are linked to decreases in the average level of cortisol over a 24-hour period, suggesting that the body’s daily hormone rhythm and glucose control may be biologically connected.

85%

In hospitalized adults with moderate to severe depression, daily exposure to bright light for 30 minutes over two weeks is associated with a measurable decrease in fasting blood glucose levels compared to exposure to dim light.

77%