I sleep at least 6 hours a night but still persistently fatigued. what can i do to feel rested ?

Sleep more: Study after study confirms the human need for 8 hours per night for optimal health and performance. Try getting a few days back to back of 8 hours per night. If you don't notice an increase in alertness after that you should consult your physician to check for dietary deficiencies or metabolic issues or even a sleep study to rule out sleep apnea or other malady. Buenos suerte!