Hemodialysis increases the preference for salt in soup.

Eighteen hemodialysis patients rated 7 concentrations of salt in soup immediately before dialysis and 24 h later. Preference ratings were higher after dialysis. Patients over 65 years old did not increase their ratings. Hypertensive patients increased their preference for salt after dialysis like normotensives, but rated lower concentrations of salt as more intense and were less able to discriminate the intensity of salt taste. The findings suggest that humans may respond to reductions in bodily sodium with a delayed increase in preference for salt.

Bone loss in patients with chronic renal disease: prediction with quantitative bone scintigraphy with SPECT.

PURPOSE: To determine whether quantitative bone scintigraphy (QBS) with single-energy photon emission computed tomography (SPECT) can help predict which patients with chronic renal disease will show bone mineral density (BMD) loss. MATERIALS AND METHODS: In 18 patients, the percentage of injected dose of technetium-99m methylene diphosphonate per cubic centimeter of bone was measured with QBS SPECT in the lumbar vertebrae and femoral neck. The differences in BMD over an average of 20 months were measured and compared with SPECT measurements. QBS values were also compared with serum bone turnover markers. RESULTS: There was a negative correlation (r = -.54, P < .05 for the lumbar spine and r = -.60, P < .01 for the femoral neck) between QBS values and bone loss. Positive and negative predictive values, sensitivity, and specificity of QBS for bone loss in the lumbar spine were 78%, 71%, 78%, and 71%, respectively, and in the femoral neck, 82%, 100%, 100%, and 78%, respectively. Differences between predictive values of serum bone turnover markers were not statistically significant. CONCLUSION: QBS with SPECT enabled prediction of rapid bone loss in patients with renal disease.

Influence of the time of day on physical performance in patients with coronary artery disease.

The exercise training workload for cardiac patients is determined from the peak heart rate achieved safely during a stress test. Circadian rhythms may play a key role in changing physiological responses to the stress test. Therefore, the purpose of this study was to evaluate the influence of the time of day on cardiopulmonary and metabolic responses in highly trained men with coronary artery disease. A group of 15 patients with coronary artery disease [53.5 (SD 6) years] performed two sessions of graded tests to exhaustion: one session was performed at 10 a.m. and the second at 5 p.m. in randomized order. Treadmill velocity was kept constant at a speed of 4.8 km h-1 starting with an elevation of 0% which was increased thereafter by 2.5% every 3 min. At rest the results revealed that only oxygen uptake was significantly lower (P < 0.05) in the morning compared to that observed in the evening [2.9 (SD 0.4) compared to 3.5 (SD 0.5) ml O2.kg-1.min-1, respectively]. During exercise, differences due to time of day were found in the variables of maximal oxygen uptake which were significantly higher (P < 0.05) in the evening than in the morning [34.2 (SD 2.6) and 40.8 (SD 2.5) ml O2.kg-1.min-1, respectively]. These data indicated that in these well-trained coronary artery disease patients there was a significant time of day effect associated with metabolic responses following stress-testing.

Exercise tolerance of end-stage renal disease patients.

The purpose of this study was to evaluate the exercise tolerance of end-stage renal disease patients, and to examine pulmonary function and blood lactate as its possible limiting factors. Ten end-stage renal disease patients (age 30 +/- 11) were tested at rest and in a subsequent graded treadmill test to exhaustion. Velocity was 4.8 km/h and the grade was incremented by 2.5% every 4 min. One minute of rest, used for blood sampling, separated successive stages. Pulmonary functions (FVC, FEV1) at rest were both 76% of predicted. Resting heart rate, systolic and diastolic blood pressures, and ventilatory equivalent values were higher than normal. At peak exercise, heart rate, oxygen uptake, oxygen pulse and blood lactic acid were lower than normally predicted for maximal exercise, while ventilatory equivalent and diastolic blood pressure were higher. Only six patients reached blood lactate levels beyond 4 mM.l-1 (onset of blood lactic acid), at which point they utilized 88 +/- 5% of their respective peak Vo2. The results suggest that the low exercise tolerance demonstrated in end-stage renal disease patients is not limited by the somewhat compromised pulmonary capacity or by excessive blood lactate levels.

Effect of running versus isometric training programs on healthy elderly at rest.

Left ventricular function and hemodynamic alterations at rest were measured echocardiographically following running or isometric training in 40 healthy elderly. They were randomly assigned into two groups. Twenty (67 +/- 4 years) were engaged in running and 20 (67.8 +/- 3.8 years) in isometric training programs. All subjects underwent a 12-week program, 3 times a week 30 min each session. The running exercise (REX) group had an aerobic exercise conditioning program at 70% of their VO2max. The program for the isometric exercise (IEX) group included weight lifting utilizing large muscle mass at 30% of their maximal voluntary contraction. After training, the REX group increased significantly (p less than 0.05) their VO2max from 2.08 +/- 0.37 to 2.36 +/- 0.41 liter/min and ejection fraction 56 +/- 5.9 to 62 +/- 6.1%. They decreased significantly their heart rate, from 73 +/- 7 to 65 +/- 7 beats/min. No change occurred in the IEX group in left ventricular function and hemodynamic parameters. These data suggest that left ventricular responses at rest differ between the two groups following a short-term training with a favorable response after REX training. In addition, this study demonstrated that a controlled aerobic training program is a better way to improve physical capacity than is a weight lifting program for trained healthy elderly.

Aging and the effect of increased after-load on left ventricular contractile state.

Hemodynamic and contractile states were studied echocardiographically in 10 young (28 +/- 3 yr) and 10 elderly (67 +/- 4 yr) male subjects at rest and during upright isometric exercise which involved the hands, hips, legs, and lower back muscle groups (deadlift) at 30% of maximum voluntary contraction for 3 min. During deadlift, both groups showed similar and significant increases in blood pressure and heart rate, compared to the resting values. Ejection fraction at rest did not differ significantly between the two groups. During deadlift, it remained unchanged in the elderly white ejection fraction increased significantly in the younger subjects. No significant changes in left ventricular end-diastolic volume occurred in either group during deadlift. End-systolic volume remained unchanged in the elderly while it decreased significantly in the younger subjects. These data indicate that cardiovascular responses and contractile state in normal young men and normal exercise-trained elderly subjects were augmented during upright sub-maximal isometric deadlift exercise, utilizing large muscle mass. However, left ventricular contractility increased less in the elderly subjects compared to the younger subjects.

Cardiovascular response during upright isometric dead lift in young, older, and elderly healthy men.

Isometric exercises raise the mean arterial blood pressure and impose serious stress on left ventricular function. It may be more dangerous for older than for younger people. The effect of aging on blood pressure response was studied in 75 subjects, 25 normal young men aged 25 +/- 4 years, 25 older men aged 51 +/- 3.2 years, and 25 elderly men aged 68 +/- 4 years, during upright isometric dead lift at 30% maximal voluntary effort for 3 min. The heart rate, systolic blood pressure, and diastolic blood pressure were measured during the 3rd min of dead lift contraction. Tension exerted was significantly lower in the older group (33 +/- 4 kg) and lowest in the elderly group (26.9 +/- 6 kg) compared with the young group (43 +/- 8 kg). All groups showed similar and significant increases in heart rate, systolic and diastolic blood pressure during dead lift (p less than 0.01). These data indicate a similar pattern of blood pressure response to acute pressure overload in young, older, and elderly normal men.

Left ventricular and hemodynamic responses during upright isometric exercise in normal young and elderly men.

Cardiovascular responses were studied echocardiographically in 10 young (23 +/- 3 years) and 10 elderly (67 +/- 4 years) men, during upright isometric handgrip and deadlift. During handgrip and deadlift both groups showed significant increases in systolic and diastolic blood pressure. Those responses were significantly greater in both groups during deadlift. Heart rate was significantly higher in both groups during deadlift than resting and handgrip values. Oxygen uptake increased progressively and significantly across conditions, and was significantly higher for the younger subjects. Ejection fraction remained unchanged during handgrip in both groups. During deadlift it remained unchanged in the elderly while it increased significantly in the younger. Both groups increased significantly heart volumes from rest to handgrip. During deadlift end systolic volume was significantly lower from resting and handgrip values only in the young group. These data indicate a similar cardiovascular response to acute pressure overload in both groups.

Externally applied abdominal vibration as a method for improving efficiency of peritoneal dialysis.

We studied the effect of externally applied vibration onto the abdominal wall on the efficiency of peritoneal dialysis (PD). Ten patients were studied. Three consecutive PD exchanges (control sessions, CS) were compared with vibration sessions (VS). Samples of blood and dialysate were analyzed for urea nitrogen (UN), creatinine (Cr) and potassium (K). Mean clearance was calculated. We found that vibration increased significantly the mean UN, Cr and K clearances.