DAILY ENERGY-REQUIREMENTS IN HEART-FAILURE PATIENTS

Diminished body cell mass in heart failure patients contributes to poo r prognosis and decreased quality of life, The level of daily energy i ntake needed to maintain body cell mass and optimal physiological func tion in heart failure patients is unknown, Thus, we examined daily ene rgy expenditure in free-living heart failure patients to estimate dail y energy requirements. Daily energy expenditure (doubly labeled water) and its components (resting and physical activity energy expenditures ) were measured in 26 heart failure patients (25 men and one woman age d 69 +/- 7 years) and 50 healthy controls (48 men and two women aged 6 9 +/- 6 years). Resting energy expenditure was measured by indirect ca lorimetry; physical activity energy expenditure from the difference be tween daily and resting energy expenditure; body composition by dual-e nergy x-ray absorptiometry; leisure time physical activity from a ques tionnaire; and peak oxygen consumption ([peak (V) over dot o(2)] n = 1 6 heart failure patients) from a treadmill test to exhaustion. Plasma markers of nutritional status were also considered. Daily energy expen diture was 17% lower (2,110 +/- 500 v 2,543 +/- 449 kcal/d) and physic al activity energy expenditure 54% lower (333 +/- 345 v 728 +/- 374 kc al/d) in heart failure patients compared with healthy controls. Daily energy expenditure was related to physical activity energy expenditure (r = .79, P < .01), resting energy expenditure (r = .63, P < .01), le isure time physical activity (r = .63, P < .01), and peak (V) over dot o(2) (r = .58, P < .01) in heart failure patients. Stepwise regressio n analysis showed that daily energy requirements in heart failure pati ents were best estimated by a combination of resting energy expenditur e and reported leisure time physical activity (total R-2 = 61%; standa rd error of the estimate, +/-333 kcal/d). Daily energy requirements pr edicted from equations derived in healthy elderly were inaccurate when applied to heart failure patients, deviating -10% to +30% from measur ed daily energy expenditure, We conclude that despite low levels of ac tivity, markers of physical activity predicted daily energy needs in h eart failure patients, We provide a new equation to estimate energy ne eds in free-living heart failure patients based on measurements of dai ly energy expenditure. Copyright (C) 1997 by W. B. Saunders Company.