You’re tired all the time
If you aren’t getting enough vitamin D, you may feel completely exhausted, even if you get plenty of sleep. “There is mounting evidence that vitamin D deficiencies are associated with fatigue and sleep disorders,” says Catherine G. R. Jackson, PhD, a professor of kinesiology and exercise science at California State University in Fresno. A study in the North American Journal of Medical Sciences found that people who felt tired had low levels of vitamin D, but raising their vitamin D to normal levels significantly reduced feelings of fatigue. Not the problem for you? You may have one of these other 13 medical conditions for feeling tired all the time.