Physical Activity in Dialysis: Clinical and Biological Impact

Physical inactivity is known to increase the risk of developing many diseases as cardiovascular diseases, diabetes, some cancers, and other chronic diseases. The impact of the inactivity is even higher in a fragile population as patients with Chronic Renal Failure (CRF) who need dialysis. This can lead to serious adverse events during the lifetime of these patients, such as arteriopathy which can result in amputation, deterioration of general condition, loss of independence and depression of wasting away. Despite the need to promote physical activity in this population of hemodialysis patients with CRF, little is known about the effects of a supervised physical activity conducted in these patients. With this study, the investigators propose to assess the effects of a physical activity program on several parameters, in hemodialysis subjects.

The health risk of a sedentary and inactive lifestyle is known in the general population, increasing the risk of diabetes (+ 25%), obesity, arterial hypertension, stroke, myocardial infarction and the development of certain cancers. Sedentary lifestyle therefore decreases longevity and life expectancy by 5 and 8 years respectively. At the same time, the benefits of physical activity (PA) are recognized (the list is not exhaustive): * Factor for improving physical capacity, * Preventive effect on many cardiovascular risk factors, * Improvement of psychological well-being (anxiety, depression, stress, etc.), * Cognitive functions, reduction in the rate of certain cancers (colon and breast mainly), * Reduction of oxidative stress. The High Authority of Health (HAS) recognizes physical activity as a therapy on its own in the prevention of chronic diseases after having noticed the harmful effects of physical inactivity (PI) on life expectancy. PI is believed to be responsible for 1.9 million deaths worldwide each year, increasing public health costs, estimated at 150-300 euros per year and per citizen. The population of patients with Chronic Renal Failure (CRF) on dialysis has a low physical capacity, a low level of PA decreasing as the number of years of dialysis increases. These parameters are correlated with mortality: a critical number of steps of less than 4000 per day, or activity less than 50 minutes per day without dialysis significantly worsens mortality. The association between mortality and level of PA is linear and this linearity is maintained over time. CRF and dialysis promote catabolic factors in metabolism, decline in muscle mass and strength to sarcopenia (associated with inflammation, hypoandrogenism, intakes of inadequate protein, metabolic acidosis, insulin resistance and inactivity). The decline in physical performance promotes falls, fractures, loss of autonomy, the number of hospitalizations which indirectly increases public health costs. Several studies have shown the benefit of developing a per-dialytic PA program providing benefits in quality of life, physical capacity, reduction of hypotension blood pressure, depression, and VO2 max. Resistance exercise also improves muscle mass and strength. PA acts as a cardioprotector by lowering total cholesterol, triglycerides, improving blood pressure profile, and consequently reducing the number of cardiovascular events on a follow-up of 2 years. Finally, the DOPPS 2009-2011 observational study demonstrates the link between the level of physical aerobic activity and the parallel decline in mortality. In addition, peripheral vascular and arterial complications are common in patients with CRF and dialysis. The prevalence of symptomatic Obstructive Arterial Disease of the Lower Limbs is estimated between 20% and 25% but it reaches 40% in the Japanese study of Matsuzawa, and 70% if associating the numerous asymptomatic patients. Associated with the aging of the population and increasing sedentary lifestyle, we are faced with the appearance of extremely serious ischemic trophic disorders, difficult to treat, despite taking appropriate medical, surgical and cicatricial load often resulting in amputation, deterioration of general condition, loss of independence, depression of wasting away. There is also an increased risk of associated cardiovascular mortality even in asymptomatic patients. The more severe the arterial disease is, greater the risk is. Thus, patients with critical ischemia have a one-year mortality of 25%. Despite the importance of these data, associated with the individual consequences following amputations, the medical interest in this pathology is relatively low, and there are only few studies in hemodialysis subjects. Exercise, especially walking, is recommended for patients at the stage of intermittent claudication. A meta-analysis performed in the general population showed that gait training improved walking ability by 150%. The main objective of this study is to assess the clinical benefit of a physical activity program in terms of performance on the 6-minute walk test. One of the secondary objectives of this study will be to assess the impact of a PA program on the occurrence of Obstructive Arterial Disease of the Lower Limbs. The investigators want to check whether the implementation of a program of per-dialytic physical activity would improve the microcirculation of the lower limbs and reduce the complications of arteritis.