**6.1 Muscle structure and function**

After a six-month exercise programme in HD patients, histological testing revealed a 51% increase in type II fibres and a 29% increase in average fibre area. There was also an increase in capillary density and mitochondrial regeneration [58]. Cross-sectional fibre area increased by 46% after 6 months of AE treatment, although another study found a drop in the percentage of atrophic fibre types I, IIa, and x as a result (from 51, 58, and 62% to 15, 21, and 32%, respectively). The therapy also improved the capillary network in the muscles. After a 12-week intradialytic progressive RE, there was a rise in thigh muscle volume [59]. The increased mitochondrial number and greater rate of protein synthesis that come with strength PE may also result in an increase in aerobic capacity. PE A rise in calcium levels in the cell cytoplasm, a surge in ATP production, and the creation of reactive oxygen species are all associated with endurance training, according to research [60]. Changes in mitochondrial function can occur after a few weeks of physical exertion (PE), and the degree of change is inversely proportional to PE intensity.

When looking at the effects of PE on adult CKD patients, a systematic review found that it had a significant favourable impact on metrics such as walking capacity, CV dimensions, and physical fitness [14]. Studies on exercise's positive effects on cardiopulmonary function, muscle strength, and walking ability in people with CKD revealed a meta-analysis [61].

A recent systematic review and meta-analysis found that resistance training, rather than aerobic training, significantly increased leg mass. After undergoing RE, my grip and knee extension strength significantly increased. AE claims to have enhanced the STS short form, but there is not enough proof to back them up. The 6-minute walking test score and the median version of the STS test in the physical performance dimension were both improved by AE and RE [62]. High-intensity resistance (RE) training on dialysis patients may increase muscular growth and strength, especially in the trained muscles. If dialysis patients desire to improve their physical performance, they can use AE and RE.
