The goal of this randomized intervention trial is to determine the effect of bright light therapy on sleep disturbance, as well as to investigate the impacts of bright light therapy on biological age measured by clinical biomarkers. The main questions it aims to answer are:

• Does bright light therapy improve sleep patterns (i.e., sleep onset latency, sleep disturbance, and sleep efficiency) in lung cancer patients?
• Can bright light therapy slow the rate of aging measured by biological age in lung cancer patients? Researchers will compare bright light therapy group to control group to see if bright light works to reduce sleep disturbance and decelerate biological aging.

Participants will:

• Receive bright light exposure or usual light exposure every day for 4 weeks
• Get blood draw at the baseline and at 4 weeks for clinical biomarkers tests
• Complete self-reported sleep, fatigue and stress surveys at the baseline and at 4 weeks
• Keep a daily sleep log

Inclusion Criteria:

• >=18 years of age
• Stage Ib to IIIb primary lung cancer diagnosis
• >=2 months after completion of primary therapy, patient can continue to be on maintenance/immunotherapy
• ECOG performance status is 0 or 1
• Experience problematic sleep (scores of >=8 on the Insomnia Severity Index)
• Able to understand, speak, and read English
• Sighted and mentally competent to consent

Exclusion Criteria:

• Pregnant women
• Have metastatic cancer
• on oxygen therapy
• Current diagnosis of seasonal affective disorder or substance abuse
• Engage in shift work or travel across >3 time zones within 2 weeks prior to the study
• Are currently being treated for sleep apnea, restless legs syndrome, or narcolepsy
• Take prescribed sedative hypnotics or antipsychotics
• Have eye conditions (glaucoma or retinal disease), problem triggered by bright light (e.g., migraine), or take photosensitizing medications (e.g., some porphyrin drugs, antipsychotics, antiarrhythmic agents)
• Participants with an Insomnia Severity Index <8
• Participants with cognitive impairment (sores of <3 mini-cog test)