One of the first signs of a vitamin B12 deficiency is frequent mental and physical fatigue regardless of how much sleep the person is getting. If an individual consistently gets a full eight hours of sleep every night and is still falling asleep during lunchtime, then a lack of vitamin B12 could be to blame. Much like muscle fatigue, too little oxygen in the red blood cells can lead to chronic lethargy.
This site offers information designed for educational purposes only. You should not rely on any information on this site as a substitute for professional medical advice, diagnosis, treatment, or as a substitute for, professional counseling care, advice, diagnosis, or treatment. If you have any concerns or questions about your health, you should always consult with a physician or other healthcare professional.