As long sunny days turn shorter and darker some people begin to experience seasonal depression. But, many of us are already feeling low-grade depression due to COVID-19 restrictions, which could turn fall and winter into a real mental health struggle. He said committing to an exercise program is a great place to start because exercise — just about any type — has a positive impact on mood. “We know a good biological treatment for depression is called activity scheduling,” said Dr. Bea. He said sitting in front of a therapy light for 30 minutes every day is an additional measure for fighting seasonal depression.