Vitamin B12 & Exercise

Some people take vitamin B12 to enhance energy and decrease fatigue. However, unless you have a deficiency, extra B12 is unlikely to give you added energy. A deficiency in B12 may affect your ability to exercise. Consult your doctor if you think you are deficient in vitamin B12 and consume foods rich in B12 instead of turning to injections or supplementation.

Exercise (Image: Siri Stafford/DigitalVision/Getty Images)

What is Vitamin B12?

Vitamin B12, known as cobalamin, is a water-soluble vitamin part of a group of eight B vitamins. This group of vitamins, also called B-complex vitamins, is necessary for healthy skin, hair, eyes and liver. Vitamin B12 helps you maintain healthy nerve cells and red blood cells and proper immune function. It also assists in the production on DNA and RNA.

B12 Deficiency

According to, studies have shown that vitamin B12 deficiency can lead to abnormal neurologic and psychiatric symptoms. These symptoms include fatigue, shaky movements, muscle weakness, incontinence, vision problems and mood disturbance. People at risk for B12 deficiency are vegetarians, elderly people and breastfed infants. Pregnant women who have increased B12 requirements are also at risk for deficiency.


Vitamin B12 assists your body in converting carbohydrates into glucose. Your body uses this glucose for energy. Before exercise, you need to consume carbohydrates to have the energy to get through your workout. If you have a B12 deficiency, these carbohydrates will not properly be converted into energy, which will leave you feeling fatigued and unable to finish your workout.

Also, since B12 aids in immune function, you may not feel well enough to exercise or you may be more susceptible to germs from your local gym if you have a deficiency.


Your daily recommendation for vitamin B12 is 2.4 mcg. It is found in animal foods, such as, fish, shellfish, dairy products, eggs, beef and pork. An example of a day's supply of B12 is one chicken breast, one hard boiled egg and one cup plain low-fat yogurt. Adults over the age of 50 may benefit from taking a B12 supplement or eating foods fortified with vitamin B12.

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