D-vitamin

Sun is starting to shine also in Finland and it makes me to wake up when light enters to my room through the curtains. I started to think does the light make waking up easier because during the winter getting up seems to be harder because the lack of the light. But in Spain I always woke up in a very dark room thanks to "persianas" and I do not remember to be struggling to get up from the bed. The recent debate about the importance of D-vitamin for your energy level made me think that maybe I am getting now D-vitamin more and that is why getting up from the bed is easier. Apparently I never had a lack of D-vitamin in Spain. Also one Spanish exchange student felt very tired all the time during the winter and after he started to take D-vitamin he felt that he had more energy.