We know exercise is a crucial component in reaching your body goals, but it shouldn’t be leaving you constantly seeking out a warm bath. If your muscles don’t seem to be recovering even on your days off, this might be explained by a thyroid problem. Your thyroid gland secretes hormones that control your metabolism—the body’s way of converting the food you eat into fuel. Fewer metabolism-controlling hormones mean a slower metabolism and a disruption in how your body burns energy, which can affect how your muscles feel. To counteract these symptoms, choose low-impact exercises like elliptical-stepping or swimming and increase the consumption of fish in your diet. Fish like salmon are a good source of omega-3 fatty acids, which are known to decrease the inflammation that might be contributing to your muscle and joint pain.
A vitamin is an organic compound needed in small quantities that cannot be made in cells. In human nutrition , most vitamins function as coenzymes after modification; for example, all water-soluble vitamins are phosphorylated or are coupled to nucleotides when they are used in cells.  Nicotinamide adenine dinucleotide (NAD + ), a derivative of vitamin B 3 ( niacin ), is an important coenzyme that acts as a hydrogen acceptor. Hundreds of separate types of dehydrogenases remove electrons from their substrates and reduce NAD + into NADH. This reduced form of the coenzyme is then a substrate for any of the reductases in the cell that need to reduce their substrates.  Nicotinamide adenine dinucleotide exists in two related forms in the cell, NADH and NADPH. The NAD + /NADH form is more important in catabolic reactions, while NADP + /NADPH is used in anabolic reactions.