The Effects of Exercise Training Combined With NR Supplementation on Metabolic Health in Older Individuals

The number of age-related chronic diseases (like obesity, type 2 diabetes and cardiovascular diseases) is increasing rapidly worldwide, reaching pandemic proportions. These age-related chronic diseases are associated with metabolic disturbances and mitochondrial dysfunction(definition) in humans. Nicotinamide adenosine dinucleotide (NAD) levels play an important role in energy metabolism and mitochondrial functioning and indeed it has been shown that high concentrations of NAD+ as well as a high NAD+/NADH ratio are strongly associated with metabolic and mitochondrial health. In contrast, decreased NAD+ bioavailability is reported in both ageing and obese humans as well as in diabetic mice. These findings fueled the idea of influencing NAD+ bioavailability in order to improve metabolic disturbances and mitochondrial dysfunction in humans. Supplementation with nicotinamide riboside (NR), a naturally occurring form of vitamin B3, may provide a way to boost cellular NAD+ levels. However, in contrast to animal studies, NR supplementation in humans has so far been unsuccessful in improving skeletal muscle mitochondrial function, exercise capacity or insulin sensitivity. Recently, it has been suggested that a situation where NAD+ levels become limited, is needed for NR supplementation to exert beneficial health effects. This situation could be achieved by combining exercise and NR supplementation. However, studies combining NR and exercise are lacking, which is why we would like to perform such a study here.