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Submaximal exercise as an adjunct to intravenous refeeding
0.41 EFFECT OF DAILY SUBMAXIMAL EXERCISE ON CELLULAR MEHBRANE FUNCTION DURING INTRAVENOUS REFEEDING IN NORMALNAN. J.P. Mlnei, G.A. Fantini, Y. Fang; J.D. Albert, D.G. Hesse, K.J. Tracey, S.F. Lowry and G.T. Shires. Department of Surgery and Clinical Research Center, New York Hospital-Cornell Medical Center, New York City, U.S.A.
Hormonal and substrate backgrounds have been shown to contribute to the --in viva modulation of cellular membrane function in skeletal muscle. The purpose of this study was to assess the extent to which daily submaximal exercise (35% VO max) during intravenous refeeding may impact upon cellular membrane function, thr&gh hormonal mechanisms or otherwise. IJsing a modified Ling-Gerard microelectrode, the resting transmembrane potential (Em) was measured in the tibialis anterior muscle of 7 male volunteers (age 24-30) in the postabsorptive state (PA), after 10 days of starvation (STARV), and following 10 days of refeeding (0.30 gm N/Kg-day; 30 non-protein Kcal/Kgday) with exercise (IVF+RX). Plasma samples (at the time of Em measurement) were analyzed for insulin (INS), eplnephrine (EPI), cortisol (CORT) and glucagon (GLUC). Em (4lV)
PA ?%ARv IVF + EX “p < 0.05
INS (uU/ml ) 23
74 T 1' vs
PA; F*p
(pg/ml) 87 + 13
EPI
26 ++ 4*"
79 T+ 1* 1 74
53 T a*
13**
50 + 10"
110 T 17
< 0.05
CORT (nghl)
vs TVF + EK by ANOVx/Newman-Keuls;
GLUC (pghl)
100 + 23
95 + 26
94 + 27
125 5 20
110 T 20 mean + SEM
120 z 25
These data indicate that the use of daily submaximal exercise during intravenous refeeding does not acutely impact upon resting Em in skeletal muscle, as these Rm data are not different from those previously reported during intravenous refeeding without exercise. Hormonal profiles are consistent with the previously advanced concept that during intravenous feeding, sole elevations of plasma Insulin are not sufficient for membrane repolarization; rather, a stress hormonal milieu may be required.
0.42
SUBMAXIMALEXERCISE AS AN ADJUNCT TO INTRAVENOUS REFEEDING. Y. Fong, K.J. Tracey, D.G. Hesse, J.D. Albert, A. Legaspi, S.F. Lowry, Department of Surgery, New York HospitalCornell Medical Center, New York City, USA The peripheral nitrogen wasting and loss of functional capacity caused by immobilization and malnutrition of hospitalization and disease are not readily corrected by refeeding alone. In order to assess submaximal exercise as an adjunctive anabolic stimulus to intravenous refeeding in the depleted subject, 14 volunteers (age 27.0 f 1.0 yr) were studied in the post-absorptive state(PA); after 10 days of total starvation(STV); and then after 10 days of intravenous refeeding(IVF) (30 non-protein calories/kg/day, O.SOgN/kg/day). Subjects were randomized into a control group(IVF-EX)and agroup(IVF+EX) that performed 1 hour of submaximal (35% V02max)stationary bicycle exercise daily during the period of intravenous refeeding. Urinary nitrogen balance(NBal), resting energy expenditure(REE), and maximal oxygen consumption(V02max) were determined. Extremity plasma total amino acid(TAA) flux was determined by simultaneous sampling of arterial and femoral venous blood and determination of extremity blood flow(EBF) b electrocapacitance plethysmography. Flux (nmol/min/lOOcct~issue)= EBF(l- Hct)([AAf art-[AA]ven). Results are mean f SEM; * = ~~0.05 vs. PA; t = ~~0.05 vs. STV. PA (n=14) -0.12+0.01 NBal (gmN/kg/day) -950?150 TAA flux 20.4kO.9 REE(Kcal/kg/day) V02max(change vs. PA)
STV (n=14) -0.095+0.009* -7OOt160 19.8kO.8 -10 + 3
IVF-EX (n =7)
IVF+EX(n=7)
0.12*0.01*t +30?160*t 24.4*0.90*t -2o+ 7
0.11~0.01"t -39* 48"t 24.5c1.3*1 -2224
Although there were no significant differences between the IVF-EX and the IVFtEX groups, daily submaximal exercise did not seem detrimental during the recovery phase from moderate malnutrition. In contrast to previous reports of exercise-induced improvements in nitrogen accrual and functional capacity in weight-stable subjects, it appears other anabolic stimulae in addition to submaximal exercise during refeeding are required for such improvements indepleted subjects. 29
Hormonal and substrate backgrounds have been shown to contribute to the --in viva modulation of cellular membrane function in skeletal muscle. The purpose of this study was to assess the extent to which daily submaximal exercise (35% VO max) during intravenous refeeding may impact upon cellular membrane function, thr&gh hormonal mechanisms or otherwise. IJsing a modified Ling-Gerard microelectrode, the resting transmembrane potential (Em) was measured in the tibialis anterior muscle of 7 male volunteers (age 24-30) in the postabsorptive state (PA), after 10 days of starvation (STARV), and following 10 days of refeeding (0.30 gm N/Kg-day; 30 non-protein Kcal/Kgday) with exercise (IVF+RX). Plasma samples (at the time of Em measurement) were analyzed for insulin (INS), eplnephrine (EPI), cortisol (CORT) and glucagon (GLUC). Em (4lV)
PA ?%ARv IVF + EX “p < 0.05
INS (uU/ml ) 23
74 T 1' vs
PA; F*p
(pg/ml) 87 + 13
EPI
26 ++ 4*"
79 T+ 1* 1 74
53 T a*
13**
50 + 10"
110 T 17
< 0.05
CORT (nghl)
vs TVF + EK by ANOVx/Newman-Keuls;
GLUC (pghl)
100 + 23
95 + 26
94 + 27
125 5 20
110 T 20 mean + SEM
120 z 25
These data indicate that the use of daily submaximal exercise during intravenous refeeding does not acutely impact upon resting Em in skeletal muscle, as these Rm data are not different from those previously reported during intravenous refeeding without exercise. Hormonal profiles are consistent with the previously advanced concept that during intravenous feeding, sole elevations of plasma Insulin are not sufficient for membrane repolarization; rather, a stress hormonal milieu may be required.
0.42
SUBMAXIMALEXERCISE AS AN ADJUNCT TO INTRAVENOUS REFEEDING. Y. Fong, K.J. Tracey, D.G. Hesse, J.D. Albert, A. Legaspi, S.F. Lowry, Department of Surgery, New York HospitalCornell Medical Center, New York City, USA The peripheral nitrogen wasting and loss of functional capacity caused by immobilization and malnutrition of hospitalization and disease are not readily corrected by refeeding alone. In order to assess submaximal exercise as an adjunctive anabolic stimulus to intravenous refeeding in the depleted subject, 14 volunteers (age 27.0 f 1.0 yr) were studied in the post-absorptive state(PA); after 10 days of total starvation(STV); and then after 10 days of intravenous refeeding(IVF) (30 non-protein calories/kg/day, O.SOgN/kg/day). Subjects were randomized into a control group(IVF-EX)and agroup(IVF+EX) that performed 1 hour of submaximal (35% V02max)stationary bicycle exercise daily during the period of intravenous refeeding. Urinary nitrogen balance(NBal), resting energy expenditure(REE), and maximal oxygen consumption(V02max) were determined. Extremity plasma total amino acid(TAA) flux was determined by simultaneous sampling of arterial and femoral venous blood and determination of extremity blood flow(EBF) b electrocapacitance plethysmography. Flux (nmol/min/lOOcct~issue)= EBF(l- Hct)([AAf art-[AA]ven). Results are mean f SEM; * = ~~0.05 vs. PA; t = ~~0.05 vs. STV. PA (n=14) -0.12+0.01 NBal (gmN/kg/day) -950?150 TAA flux 20.4kO.9 REE(Kcal/kg/day) V02max(change vs. PA)
STV (n=14) -0.095+0.009* -7OOt160 19.8kO.8 -10 + 3
IVF-EX (n =7)
IVF+EX(n=7)
0.12*0.01*t +30?160*t 24.4*0.90*t -2o+ 7
0.11~0.01"t -39* 48"t 24.5c1.3*1 -2224
Although there were no significant differences between the IVF-EX and the IVFtEX groups, daily submaximal exercise did not seem detrimental during the recovery phase from moderate malnutrition. In contrast to previous reports of exercise-induced improvements in nitrogen accrual and functional capacity in weight-stable subjects, it appears other anabolic stimulae in addition to submaximal exercise during refeeding are required for such improvements indepleted subjects. 29