The prevalence of chronic kidney disease (CKD) is increasing, with approximately 10% of adults worldwide at some stage of the disease and 1.2 million deaths per year [1,2]. In Brazil, data from the last census indicate more than 144 thousand patients living with CKD in 2020, of which 93.6% undergo hemodialysis treatment [3].

Patients on hemodialysis commonly have a poor quality of life, which portends an increased risk of hospitalization and mortality [4]. Indeed, poor quality of life is associated with symptoms of depression, recurrent infections, pain, anaemia, post-HD weakness, and poor adherence to medication use [5]. Many strategies have been studied to improve the quality of life of these patients, and among them is practising physical exercise [6].

The National Kidney Foundation has recommended physical exercises for patients with CKD similar to the general population, with 30 min of aerobic exercise per day most days [7]. However, it is known that patients under dialysis usually have low levels of physical activity and tend to have a sedentary lifestyle, which is associated with an increased risk of mortality in this population [8]. Data show that HD patients have a low number of steps per day and, in addition, physical activity is lower on dialysis days than on non-dialysis and weekend days [9].

The practice of exercise provides favourable effects in treating and preventing several diseases. In CKD, “exercise as medicine” has been used for improved health-related outcomes, such as hypertension, cachexia, and functional capacity [10]. In addition, reducing sedentary behaviour can improve health-related quality of life [11].

The present pilot study hypothesizes that physical exercise may improve the quality of life and aerobic fitness in patients with CKD undergoing HD. Thus, this study aimed to evaluate the effect of a 12-week intradialytic aerobic exercise program on the quality of life, aerobic fitness, and dialysis adequacy of patients with CKD on hemodialysis.