Mitochondrial function should not be confused with mitochondrial disease.
Mitochondria are energy, there are different types of cell in the body (brain, muscle etc), the energy supplied to them is the same by mitochondria.
If mitochondria is not working properly then all muscle function is impaired. This includes the heart and can lead to huge problems with blood circulation problems and cold limbs, poor temperature regulation. Low cardiac output can lead to chronic fatigue symptoms. Low blood pressure.
I have often read postings on curezone asking why do I have cold limbs, often put down to circulation problems, it is the mitochondria not working properly that is the answer.
Biocare sell preparations targeting the mitochondria. A good antioxadant is Cellguard forte.
Antioxidants are very important if you suffer from mitochondrial dysfunction.
Toxins can effect the mitochondria too, bacterial or viral, peptide complexes,
Dysbiosis can effect your mitochondria.
Mitochondria have very specific nutritional requirements. Biotin, B vitamins, vit c, co Q 10 alc, d ribose etc...