Chronic kidney disease (CKD) affects between 5-10% of the world's population, equating to ~740 million people worldwide. End stage renal disease (ESRD) is the result of a progressive loss of kidney function where the patient requires dialysis to replace the typical functions of the kidney. The quality of life of these individuals can be poor as a result of various complications associated with CKD (e.g. heart disease, diabetes, muscle wastage, decreased fitness). In an attempt to combat reduced physical fitness, many studies have applied long term exercise programmes. However, the body's response to exercise in people with CKD is not well understood and a set of guidelines that informs safe and effective exercise prescription is lacking.

Chronic kidney disease (CKD) affects between 5-10% of the world's population, equating to ~740 million people worldwide. End stage renal disease (ESRD) is the result of a progressive loss of kidney function where the patient requires dialysis to replace the typical functions of the kidney. The quality of life (QOL) of these individuals is severely impaired as a result of various complications associated with CKD (e.g. heart disease, diabetes, muscle wastage, decreased fitness). In an attempt to combat this decrease in physical fitness, many studies have applied long term exercise interventions. However, the acute response to exercise in this population is not entirely understood and a comprehensive set of guidelines that informs safe and effective exercise prescription is lacking.

The use of exercise as a therapeutic intervention in ESRD has grown in popularity, and evidence provided by numerous long term studies indicates cardiopulmonary, metabolic and inflammatory system adaptations. Despite these positive findings, the specific mechanisms through which exercise benefits these patients have not yet been fully established. In addition, the extent to which 'normal' physiology is acutely altered by dialysis treatment, and the effect that aerobic exercise may have on this, is unknown.

In patients with ESRD, this study aims to characterise the acute physiological response to exercise under different conditions. In doing so, the study aims to inform the development of guidelines for safe and effective intra-dialytic exercise training.

Participants with end stage renal disease

Inclusion criteria

• On hemodialysis for at least 3 months.
• 4 hours of dialysis 3 times per week.
• Urea reduction rate of at least 65% during the three months before enrolment.
• Age 18 years or older.
• Able to complete the CPEX and CLE test.

Exclusion criteria

• Clinically significant valvular insufficiency.
• Clinically significant dysrhythmia.
• Uncontrolled intra-dialytic blood pressure (systolic > 180, diastolic >95).
• Excessive fluid accumulation between dialysis sessions (>3 liters).
• Hemoglobin unstable (below 9.0 g/dL).
• Ischemic cardiac event (<1 month).
• Unable to exercise.
• Morbidly obese (BMI > 40).
• Clinically significant and still active inflammatory or malignant process.
• Planned kidney transplant during the duration of study.

Healthy participants

Inclusion criteria

• Age 18 years or older.
• Able to complete the CPEX and CLE test.

Exclusion criteria

• Significantly limiting disease or comorbidity which would prevent full participation in exercise testing or illicit an abnormal cardiorespiratory response to exercise.
• Chronic kidney disease.

Participants with end stage renal disease:

Patients will be recruited from the University Hospitals Coventry & Warwickshire hemodialysis unit identified by the research team and renal medical professionals.

Healthy participants:

Healthy participants will be recruited from Coventry University database of previous research participants. This group will comprise of 20 participants, age and weight matched to the patients with ESRD.