Light - I think I'm quite sensitive to the changes in natural daylight and have found that my energy levels are impacted by the darker mornings and evenings of late. I usually like to wake early and start my day with my morning routine that includes some mindfulness, reading, journaling and movement - but I find it harder to wake up so early in the winter. When the mornings are lighter, I'll often do some form of movement in the garden, allowing my eyes to take in some natural daylight, which I'm sure helps strengthen my sleep patterns. Now that I'm doing my morning movement indoors, I try to replace the daylight with some bright indoor lighting and then make a point of accessing natural daylight a little later in the day.