Nutrition and Chronic Kidney Disease

Denis Fouque; Solenne Pelletier; Denise Mafra; Philippe Chauveau


Kidney Int. 2011;80(4):348-357. 

In This Article

Energy Needs and Physical Activity: A Worrying Pattern

It is cumbersome to estimate an individual's energy requirements, as energy metabolism depends on many variable factors, such as age, gender, lean body mass, climate, inflammation, thyroid and parathyroid function. Obviously, in a balanced state, energy requirements correspond to energy expenditure, thus a patient should adapt intakes to his/her expenses. Total energy expenditure is made up from three separate components: resting energy expenditure, thermic effect of meals, and physical activity energy expenditure.[87] The accurate estimation of total energy expenditure in chronic kidney patients is essential to allow an adequate provision of nutrients; however, it is a challenge to collect actual physical activity and resting energy expenditure in these patients.[88–91] There are conflicting results on resting energy expenditure during dialysis,[92] and there is no data on total energy expenditure because physical activity is hardly monitored.

We have therefore evaluated total energy expenditure during a 7-day period using a new device called SenseWear Armband (Body Media, Pittsburgh, PA), which uses sensors that continuously record movement, heat flux, and skin temperature allowing a detailed estimation of the wearer's energy expenditure, duration of physical activity, and number of steps walked.[93] We monitored 24 maintenance hemodialysis patients and compared their results to 18 age-matched healthy individuals. Total energy expenditure of maintenance hemodialysis patients was lower (29.5±6.6 kcal/kg/day) when compared with healthy individuals (31.8±7.0 kcal/kg/day), P=0.02. There was a major reduction in physical activity between patients (4810±3706 steps/day) and healthy individuals (8712±5287 steps/day), P=0.008. Total energy expenditure was positively correlated with the steps number (r=0.84, P=0.001; Figure 3).[93]

Figure 3.

Daily walking and total energy expenditure. The relationship between total daily energy expenditure (TEE) estimated by the SenseWear Armband and patient steps number (mean of 7-day recording, n=24, r=0.84, P=0.001). Healthy subjects with moderate activity usually walk more than 8000–10,000 steps per day.

We also evaluated the role of the dialysis session in daily total energy expenditure and observed that patients spent less energy (28.4±4.8 kcal/kg/day) and walked less (3629±3198 steps/day) during the dialysis days when compared with the nondialysis days (30.3±7.8 kcal/kg/day; 5323±4254 steps/day, P=0.01). This decrease in physical activity may be caused by the lack of motion during the 4-h hemodialysis procedure, the postdialysis fatigue, and the mandatory commuting time to reach the dialysis facility back and forth. As a matter of fact, Majchrzak et al.[94] also observed that physical activity was lower on dialysis days when compared with nondialysis days, suggesting targets for improving physical activity, both during hemodialysis and on nondialysis days. It is therefore mandatory to implement exercise in CKD patients, as underlined by Painter and Johansen.[95] In addition, exercise has been shown to increase nutrient utilization during intradialytic parenteral nutrition.[46] Research is also needed in order to achieve the best tolerance and identify-specific training programs (aerobic and resistance exercise) designed for CKD patients.[96]

Thus, in maintenance dialysis patients, daily energy requirements may fluctuate between 30 and 40 kcal/kg/day based on actual physical activity.[68] However, the best patient outcome will result from an increase in physical activity and a subsequent augmentation in energy intake, and this is a call for action.


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