>daytime fatigue, necessitating frequent 40 to 120 minute naps Few years ago I started to feel really sleepy, even fall asleep during daytime, especially at wi

>daytime fatigue, necessitating frequent 40 to 120 minute naps Few years ago I started to feel really sleepy, even fall asleep during daytime, especially at winter. Turned out to be vitamin D. Taking it helped tremendously. Measured recently - normal, but still slightly low. Increased dose. So the advice for everyone is: do full blood panel, including vitamin D in particular.