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Biomedical subjects

B D Levine

Publications and source records attributed to B D Levine.

At least 37 records · Page 2Linked to original sources
PubMed2000

Characteristics of inactive primary care patients: baseline data from the activity counseling trial. For the Activity Counseling Trial Research Group.

BACKGROUND: Although many primary care patients are inactive, being able to classify even small amounts and intensities of activity and factors associated with these activity levels could be helpful for physicians who are trying to motivate their patients to become more physically active. METHODS: Sociodemographics, physical activity, fitness, other cardiovascular risk factors, and psychosocial measures were measured at baseline in the 874 patients in the Activity Counseling Trial. Patients were categorized into three groups: (1) no moderate-to-vigorous physical activity (MVPA), (2) some moderate but no vigorous activity, and (3) some vigorous activity. Multiple logistic regression was used to determine factors cross-sectionally associated with activity intensity. RESULTS: One or more cardiovascular risk factors in addition to physical inactivity were present in 84% of participants. Maximal oxygen uptake averaged 25.2 ml/kg/min; 85% had poor to fair aerobic fitness. Physical activity averaged 32.7 kcal/kg/day, with 13.5 min of MVPA/day; 26% engaged in some vigorous activity, 11% engaged in no MVPA. In unadjusted analyses, gender, age, race, education, income, employment, smoking, alcohol use, and exercise self-efficacy were associated with activity intensity (P = 0.05-0.001). A greater percentage engaged in moderate than in vigorous activity in all subgroups. In multiple logistic regression analyses, odds ratios (95% confidence intervals) for engaging in vigorous activity were 0. 39 (0.28, 0.56) for women, 0.38 (0.19, 0.75) for 65+ compared with 35- to 44-year-olds, and 1.14 (1.06, 1.22) for 10-unit increases in performance self-efficacy score. CONCLUSIONS: Most primary care patients who are physically inactive have additional cardiovascular risk factors, particularly overweight and obesity. All subgroups pursue moderate-intensity activity more often than vigorous activity. Women, older persons, and those with lower exercise self-efficacy are less likely to engage in vigorous activity.

Adult↗
PubMed2000

Spontaneous fluctuations in cerebral blood flow: insights from extended-duration recordings in humans.

To determine the dependence of cerebral blood flow (CBF) on arterial pressure over prolonged time periods, we measured beat-to-beat changes in mean CBF velocity in the middle cerebral artery (transcranial Doppler) and mean arterial pressure (Finapres) continuously for 2 h in six healthy subjects (5 men and 1 woman, 18-40 yr old) during supine rest. Fluctuations in velocity and pressure were quantified by the range [(peak - trough)/mean] and coefficients of variation (SD/mean) in the time domain and by spectral analysis in the frequency domain. Mean velocity and pressure over the 2-h recordings were 60 +/- 7 cm/s and 83 +/- 8 mmHg, associated with ranges of 77 +/- 8 and 89 +/- 10% and coefficients of variation of 9.3 +/- 2.2 and 7.9 +/- 2.3%, respectively. Spectral power of the velocity and pressure was predominantly distributed in the frequency range of 0.00014-0.1 Hz and increased inversely with frequency, indicating characteristics of an inverse power law (1/f(alpha)). However, linear regression on a log-log scale revealed that the slope of spectral power of pressure and velocity was steeper in the high-frequency (0.02-0.5 Hz) than in the low-frequency range (0.002-0.02 Hz), suggesting different regulatory mechanisms in these two frequency ranges. Furthermore, the spectral slope of pressure was significantly steeper than that of velocity in the low-frequency range, consistent with the low transfer function gain and low coherence estimated at these frequencies. We conclude that 1) long-term fluctuations in CBF velocity are prominent and similar to those observed in arterial pressure, 2) spectral power of CBF velocity reveals characteristics of 1/f(alpha), and 3) cerebral attenuation of oscillations in CBF velocity in response to changes in pressure may be more effective at low than that at high frequencies, emphasizing the frequency dependence of cerebral autoregulation.

Adolescent↗
PubMed2000

Effects of whole body heating on dynamic baroreflex regulation of heart rate in humans.

The purpose of this project was to identify whether dynamic baroreflex regulation of heart rate (HR) is altered during whole body heating. In 14 subjects, dynamic baroreflex regulation of HR was assessed using transfer function analysis. In normothermic and heat-stressed conditions, each subject breathed at a fixed rate (0. 25 Hz) while beat-by-beat HR and systolic blood pressure (SBP) were obtained. Whole body heating significantly increased sublingual temperature, HR, and forearm skin blood flow. Spectral analysis of HR and SBP revealed that the heat stress significantly reduced HR and SBP variability within the high-frequency range (0.2-0.3 Hz), reduced SBP variability within the low-frequency range (0.03-0.15 Hz), and increased the ratio of low- to high-frequency HR variability (all P < 0.01). Transfer function gain analysis showed that the heat stress reduced dynamic baroreflex regulation of HR within the high-frequency range (from 1.04 +/- 0.06 to 0.54 +/- 0.6 beats. min(-1). mmHg(-1); P < 0.001) without significantly affecting the gain in the low-frequency range (P = 0.63). These data suggest that whole body heating reduced high-frequency dynamic baroreflex regulation of HR associated with spontaneous changes in blood pressure. Reduced vagal baroreflex regulation of HR may contribute to reduced orthostatic tolerance known to occur in humans during heat stress.

Adult↗
PubMed2000

Effect of head-down-tilt bed rest and hypovolemia on dynamic regulation of heart rate and blood pressure.

Adaptation to head-down-tilt bed rest leads to an apparent abnormality of baroreflex regulation of cardiac period. We hypothesized that this "deconditioning response" could primarily be a result of hypovolemia, rather than a unique adaptation of the autonomic nervous system to bed rest. To test this hypothesis, nine healthy subjects underwent 2 wk of -6 degrees head-down bed rest. One year later, five of these same subjects underwent acute hypovolemia with furosemide to produce the same reductions in plasma volume observed after bed rest. We took advantage of power spectral and transfer function analysis to examine the dynamic relationship between blood pressure (BP) and R-R interval. We found that 1) there were no significant differences between these two interventions with respect to changes in numerous cardiovascular indices, including cardiac filling pressures, arterial pressure, cardiac output, or stroke volume; 2) normalized high-frequency (0.15-0.25 Hz) power of R-R interval variability decreased significantly after both conditions, consistent with similar degrees of vagal withdrawal; 3) transfer function gain (BP to R-R interval), used as an index of arterial-cardiac baroreflex sensitivity, decreased significantly to a similar extent after both conditions in the high-frequency range; the gain also decreased similarly when expressed as BP to heart rate x stroke volume, which provides an index of the ability of the baroreflex to alter BP by modifying systemic flow; and 4) however, the low-frequency (0.05-0.15 Hz) power of systolic BP variability decreased after bed rest (-22%) compared with an increase (+155%) after acute hypovolemia, suggesting a differential response for the regulation of vascular resistance (interaction, P < 0.05). The similarity of changes in the reflex control of the circulation under both conditions is consistent with the hypothesis that reductions in plasma volume may be largely responsible for the observed changes in cardiac baroreflex control after bed rest. However, changes in vasomotor function associated with these two conditions may be different and may suggest a cardiovascular remodeling after bed rest.

Adult↗
PubMed2000

Nine months in space: effects on human autonomic cardiovascular regulation.

We studied three Russian cosmonauts to better understand how long-term exposure to microgravity affects autonomic cardiovascular control. We recorded the electrocardiogram, finger photoplethysmographic pressure, and respiratory flow before, during, and after two 9-mo missions to the Russian space station Mir. Measurements were made during four modes of breathing: 1) uncontrolled spontaneous breathing; 2) stepwise breathing at six different frequencies; 3) fixed-frequency breathing; and 4) random-frequency breathing. R wave-to-R wave (R-R) interval standard deviations decreased in all and respiratory frequency R-R interval spectral power decreased in two cosmonauts in space. Two weeks after the cosmonauts returned to Earth, R-R interval spectral power was decreased, and systolic pressure spectral power was increased in all. The transfer function between systolic pressures and R-R intervals was reduced in-flight, was reduced further the day after landing, and had not returned to preflight levels by 14 days after landing. Our results suggest that long-duration spaceflight reduces vagal-cardiac nerve traffic and decreases vagal baroreflex gain and that these changes may persist as long as 2 wk after return to Earth.

Adult↗
PubMed1999

Exercise-related syncope in the young athlete: reassurance, restriction or referral?

A common event in young adults, syncope is usually benign and only rarely requires more than simple reassurance. However, exercise-related syncope always requires investigation because it may be the only symptom that precedes a sudden cardiac death. Syncope that occurs during exercise tends to be more ominous than that occurring in the postexertional state. During the physical examination, the cardiovascular system should be evaluated carefully. An electrocardiogram is mandatory and requires close scrutiny, with further testing ordered as indicated. The investigation of syncope should specifically exclude known pathologic diagnoses before a complete return to activity is permitted. In cases where a diagnosis is not clearly established, consultation or referral may be warranted.

Adult↗
PubMed1999

Fractal fluctuations in cardiac time series.

Human heart rate, controlled by complex feedback mechanisms, is a vital index of systematic circulation. However, it has been shown that beat-to-beat values of heart rate fluctuate continually over a wide range of time scales. Herein we use the relative dispersion, the ratio of the standard deviation to the mean, to show, by systematically aggregating the data, that the correlation in the beat-to-beat cardiac time series is a modulated inverse power law. This scaling property indicates the existence of long-time memory in the underlying cardiac control process and supports the conclusion that heart rate variability is a temporal fractal. We argue that the cardiac control system has allometric properties that enable it to respond to a dynamical environment through scaling.

Adult↗
PubMed1999

The role of the right ventricle during hypobaric hypoxic exercise: insights from patients after the Fontan operation.

OBJECTIVES: The principal objective of this study was to examine the importance of the right ventricle for maximal systemic oxygen transport during exercise at high altitude by studying patients after the Fontan operation. BACKGROUND: High-altitude-induced hypoxia causes a reduction in maximal oxygen uptake. Normal right ventricular pump function may be critical to sustain cardiac output in the face of hypoxic pulmonary vasoconstriction. We hypothesized that patients after the Fontan operation, who lack a functional subpulmonary ventricle, would have a limited exercise capacity at altitude, with an inability to increase cardiac output. METHODS: We measured oxygen uptake (VO2, Douglas bag), cardiac output (Qc, C2H2 rebreathing), heart rate (HR) (ECG), blood pressure (BP) (cuff), and O2 Sat (pulse oximetry) in 11 patients aged 14.5+/-5.2 yr (mean +/- SD) at 4.7+/-1.6 yr after surgery. Data were obtained at rest, at three submaximal steady state workrates, and at peak exercise on a cycle ergometer. All tests were performed at sea level (SL) and at simulated altitude (ALT) of 3048 m (10,000 ft, 522 torr) in a hypobaric chamber. RESULTS: At SL, resting O2 sat was 92.6+/-4%. At ALT, O2 sat decreased to 88.2+/-4.6% (P < 0.05) at rest and decreased further to 80+/-6.3% (P < 0.05) with peak exercise. At SL, VO2 increased from 5.1+/-0.9 mL x kg(-1) x min(-1) at rest to 23.5+/-5.3 mL x kg(-1) x min(-1) at peak exercise and CI (Qc x m(-2)) increased from 3.3+/-0.7 L x m(-2) to 6.2+/-1.2 L x m(-2). VO2 peak, 17.8+/-4 mL x kg(-1) x min(-1) (P < 0.05), and CI peak, 5.0+/-1.5 L x m(-2) (P < 0.05), were both decreased at ALT. Remarkably, the relationship between Qc and VO2 was normal during submaximal exercise at both SL and ALT. However at ALT, stroke volume index (SVI, SV x m(-2)) decreased from 37.7+/-8.6 mL x min(-1) x m2 at rest, to 31.3+/-8.6 mL x min(-1) x m2 at peak exercise (P < 0.05), whereas it did not fall during sea level exercise. CONCLUSIONS: During submaximal exercise at altitude, right ventricular contractile function is not necessary to increase cardiac output appropriately for oxygen uptake. However, normal right ventricular pump function may be necessary to achieve maximal cardiac output during exercise with acute high altitude exposure.

Adolescent↗
PubMed1999

Effect of increasing central venous pressure during passive heating on skin blood flow.

Whole body heating in humans increases skin blood flow (SkBF) and decreases central venous pressure (CVP). This study sought to identify whether elevations in SkBF are augmented during passive heating if CVP is increased during the heat stress. Seven subjects were exposed to passive heating. Once SkBF was substantially elevated, 15 ml/kg warm saline were rapidly infused intravenously. Whole body heating significantly increased cutaneous vascular conductance and decreased CVP from 7.7 +/- 0.6 to 4.9 +/- 0.5 mmHg (P < 0.05). Saline infusion returned CVP to pre-heat-stress pressures (7.9 +/- 0.6 mmHg; P > 0.05) and significantly increased cutaneous vascular conductance relative to the period before saline administration. Moreover, saline infusion did not alter mean arterial pressure, pulse pressure, or esophageal temperature (all P > 0.05). To serve as a volume control, 15 ml/kg saline were rapidly infused intravenously in normothermic subjects. Saline infusion increased CVP (P < 0.05) without affecting mean arterial pressure, pulse pressure, or cutaneous vascular conductance (all P > 0.05). These data suggest that cardiopulmonary baroreceptor unloading during passive heating may attenuate the elevation in SkBF in humans, whereas loading cardiopulmonary baroreceptors in normothermia has no effect on SkBF.

Adult↗
PubMed1998

Usefulness of isometric hand grip exercise in detecting coronary artery disease during dobutamine atropine stress echocardiography in patients with either stable angina pectoris or another type of positive stress test.

Dobutamine atropine stress echocardiography (DASE) detects coronary artery disease (CAD) by increasing myocardial oxygen demand causing ischemia. The sensitivity of the test for detection of CAD is reduced in patients with submaximal stress. We hypothesized that increasing cardiac work load by adding isometric exercise would improve the detection of ischemia during DASE. We studied 31 patients, mean age 57+/-11 years, with angiographically documented CAD. Patients underwent DASE using incremental dobutamine doses from 5 to 40 microg/kg/min, followed by atropine if peak heart rate was <85% of predicted maximal. Hand grip was then performed for 2 minutes at 33% of maximal voluntary contraction, while dobutamine infusion was maintained at the peak dose. The addition of hand grip during dobutamine stress was associated with a significant increase in systolic blood pressure (143+/-21 vs 164+/-24 mm Hg, p = 0.001) and left ventricular end-systolic circumferential wall stress (72+/-30 x 10(3) dynes/cm2 vs 132+/-34 x 10(3) dynes/cm2, p = 0.004). Wall motion score index increased from 1.0 at rest to 1.15+/-0.18 with dobutamine (p = 0.0004 vs rest), and increased further to 1.29+/-0.22 with the addition of hand grip (p = 0.004 vs dobutamine). Ischemia was detected in 19 patients (62%) with dobutamine-atropine stress alone and in 25 (83%) after the addition of hand grip (p <0.05). The addition of hand grip during DASE is feasible, and improves the detection of myocardial ischemia.

Adult↗
PubMed1998

Transfer function analysis of dynamic cerebral autoregulation in humans.

To test the hypothesis that spontaneous changes in cerebral blood flow are primarily induced by changes in arterial pressure and that cerebral autoregulation is a frequency-dependent phenomenon, we measured mean arterial pressure in the finger and mean blood flow velocity in the middle cerebral artery (VMCA) during supine rest and acute hypotension induced by thigh cuff deflation in 10 healthy subjects. Transfer function gain, phase, and coherence function between changes in arterial pressure and VMCA were estimated using the Welch method. The impulse response function, calculated as the inverse Fourier transform of this transfer function, enabled the calculation of transient changes in VMCA during acute hypotension, which was compared with the directly measured change in VMCA during thigh cuff deflation. Beat-to-beat changes in VMCA occurred simultaneously with changes in arterial pressure, and the autospectrum of VMCA showed characteristics similar to arterial pressure. Transfer gain increased substantially with increasing frequency from 0.07 to 0.20 Hz in association with a gradual decrease in phase. The coherence function was > 0.5 in the frequency range of 0.07-0.30 Hz and < 0.5 at < 0.07 Hz. Furthermore, the predicted change in VMCA was similar to the measured VMCA during thigh cuff deflation. These data suggest that spontaneous changes in VMCA that occur at the frequency range of 0.07-0.30 Hz are related strongly to changes in arterial pressure and, furthermore, that short-term regulation of cerebral blood flow in response to changes in arterial pressure can be modeled by a transfer function with the quality of a high-pass filter in the frequency range of 0.07-0.30 Hz.

Adult↗
PubMed1998

Deterioration of cerebral autoregulation during orthostatic stress: insights from the frequency domain.

To determine whether dynamic cerebral autoregulation is impaired during orthostatic stress, cerebral blood flow (CBF) velocity in the middle cerebral artery (transcranial Doppler) and mean arterial pressure (MAP; Finapres) were measured continuously in 12 healthy subjects during ramped maximal lower body negative pressure (LBNP) to presyncope. Velocity and pressure were averaged over 6-min periods of stable data at rest and during LBNP to examine steady-state cerebral hemodynamics. Beat-to-beat variability of velocity and pressure were quantified by a "variation index" (oscillatory amplitude/steady-state mean value) and by power spectral analysis. The dynamic relationship between changes in pressure and velocity was evaluated by the estimates of transfer and coherence function. The results of the study were as follows. Steady-state MAP remained relatively constant during LBNP, whereas CBF velocity decreased progressively by 6, 15, and 21% at -30, -40, and -50 mmHg LBNP, respectively (P < 0.05 compared with baseline). At the maximal level of LBNP (30 s before presyncope) MAP decreased by 9.4% in association with a prominent reduction in velocity by 24% (P < 0.05 compared with baseline). The variation index of pressure increased significantly from 3.8 +/- 0.3% at baseline to 4.5 +/- 0. 6% at -50 mmHg LBNP in association with an increase in the variation index of velocity from 6.0 +/- 0.6 to 8.4 +/- 0.7% (P < 0.05). Consistently, the low- (0.07-0.20 Hz) and high-frequency (0.20-0.30 Hz) power of variations in pressure and velocity increased significantly at high levels of LBNP (P < 0.05) in association with an increase in transfer function gain (24% at -50 mmHg, P < 0.05). We conclude that the damping effects of autoregulation on variations in CBF velocity are diminished during orthostatic stress in association with substantial falls in steady-state CBF velocity. We suggest that these changes may contribute in part to the development of presyncope.

Adult↗
PubMed1998

Individual variation in response to altitude training.

Moderate-altitude living (2,500 m), combined with low-altitude training (1,250 m) (i.e., live high-train low), results in a significantly greater improvement in maximal O2 uptake (V(02)max) and performance over equivalent sea-level training. Although the mean improvement in group response with this "high-low" training model is clear, the individual response displays a wide variability. To determine the factors that contribute to this variability, 39 collegiate runners (27 men, 12 women) were retrospectively divided into responders (n = 17) and nonresponders (n = 15) to altitude training on the basis of the change in sea-level 5,000-m run time determined before and after 28 days of living at moderate altitude and training at either low or moderate altitude. In addition, 22 elite runners were examined prospectively to confirm the significance of these factors in a separate population. In the retrospective analysis, responders displayed a significantly larger increase in erythropoietin (Epo) concentration after 30 h at altitude compared with nonresponders. After 14 days at altitude, Epo was still elevated in responders but was not significantly different from sea-level values in nonresponders. The Epo response led to a significant increase in total red cell volume and V(O2) max in responders; in contrast, nonresponders did not show a difference in total red cell volume or V(O2)max after altitude training. Nonresponders demonstrated a significant slowing of interval-training velocity at altitude and thus achieved a smaller O2 consumption during those intervals, compared with responders. The acute increases in Epo and V(O2)max were significantly higher in the prospective cohort of responders, compared with nonresponders, to altitude training. In conclusion, after a 28-day altitude training camp, a significant improvement in 5,000-m run performance is, in part, dependent on 1) living at a high enough altitude to achieve a large acute increase in Epo, sufficient to increase the total red cell volume and V(O2)max, and 2) training at a low enough altitude to maintain interval training velocity and O2 flux near sea-level values.

Acclimatization↗
PubMed1997

Effect of high-altitude exposure in the elderly: the Tenth Mountain Division study.

BACKGROUND: More than 5 million people/year over age 60 visit high altitude, which may exacerbate underlying cardiac or pulmonary disease. We hypothesized that the elderly would exhibit an impaired functional capacity at altitude, with increased myocardial ischemia compared with sea level (SL). METHODS AND RESULTS: Twenty veterans (68+/-3 years) were studied at (1) SL, (2) acute simulated altitude to 2500 m, and (3) after 5 days of acclimatization to 2500 m. With acute altitude, PaO2 and oxyhemoglobin saturation decreased and pulmonary artery pressure increased 43%, associated with sympathetic activation. VO2peak decreased 12% acutely but normalized after acclimatization. The best predictor of VO2peak with acute altitude was VO2peak at SL (r=.94). The double product that induced 1-mm ST depression during exercise with acute altitude was 5% less than SL but normalized after acclimatization. One patient with severe coronary disease sustained a myocardial infarction after an exercise test. CONCLUSIONS: Moderate altitude exposure in the elderly is associated with hypoxemia, sympathetic activation, and pulmonary hypertension resulting in a reduced exercise capacity that is predictable based on exercise performance at SL. Patients with coronary artery disease who are well compensated at SL do well at moderate altitude, although acutely ischemia may be provoked at modestly lower myocardial and systemic work rates. The elderly acclimatize well with normalization of SL performance after 5 days. A prudent policy would be for elderly individuals, particularly those with coronary artery disease, to limit their activity during the first few days at altitude to allow this acclimatization process to occur.

Age Factors↗
PubMed1997

Cardiac atrophy after bed-rest deconditioning: a nonneural mechanism for orthostatic intolerance.

BACKGROUND: The cardiovascular adaptation to bed rest leads to orthostatic intolerance, characterized by an excessive fall in stroke volume (SV) in the upright position. We hypothesized that this large fall in SV is due to a change in cardiac mechanics. METHODS AND RESULTS: We measured pulmonary capillary wedge pressure (PCWP), SV, left ventricular end-diastolic volume (LVEDV), and left ventricular mass (by echocardiography) at rest, during lower-body negative pressure, and after saline infusion before and after 2 weeks of bed rest with -6 degrees head-down tilt (n=12 subjects aged 24+/-5 years). Pressure (P)-volume (V) curves were modeled exponentially by P=ae(kV)+b and logarithmically by P=-Sln[(Vm-V)/(Vm-V0)], where V0 indicates volume at P=0, and the constants k and S were used as indices of normalized chamber stiffness. Dynamic stiffness (dP/dV) was calculated at baseline LVEDV. The slope of the line relating SV to PCWP during lower-body negative pressure characterized the steepness of the Starling curve. We also measured plasma volume (with Evans blue dye) and maximal orthostatic tolerance. Bed rest led to a reduction in plasma volume (17%), baseline PCWP (18%), SV (12%), LVEDV (16%), V0 (33%), and orthostatic tolerance (24%) (all P<.05). The slope of the SV/PCWP curve increased from 4.6+/-0.4 to 8.8+/-0.9 mL/mm Hg (P<.01) owing to a parallel leftward shift in the P-V curve. Normalized chamber stiffness was unchanged, but dP/dV was reduced by 50% at baseline LVEDV, and cardiac mass tended to be reduced by 5% (P<.10). CONCLUSIONS: Two weeks of head-down-tilt bed rest leads to a smaller, less distensible left ventricle but a shift to a more compliant portion of the P-V curve. This results in a steeper Starling relationship, which contributes to orthostatic intolerance by causing an excessive reduction in SV during orthostasis.

Adaptation, Physiological↗
PubMed1997

Comparison of single versus multiple lifestyle interventions: are the antihypertensive effects of exercise training and diet-induced weight loss additive?

Although aerobic exercise training and diet-induced weight loss each have been shown to individually lower elevated blood pressure (BP), it is currently not known whether their combined use produces an additive antihypertensive effect. In this randomized clinical trial we therefore compared the effect on resting BP of exercise training only and dietary modification only with that of exercise training plus dietary modification in 55 sedentary, overweight patients with high normal BP or stage 1 or 2 hypertension. After baseline testing, patients were randomized to 1 of the following 3 interventions for 12 weeks: exercise training only (aerobic exercise; 30 to 45 minutes; 3 to 5 days/week; 60% to 85% of maximal heart rate), dietary modification only (aimed primarily at weight loss via restriction of energy intake and dietary fat), or exercise training plus dietary modification. Forty-eight patients completed the study. In these patients, exercise training plus dietary modification elicited a greater reduction (p < or = 0.001) in body weight (-7.1 +/- 2.9 vs -1.0 +/- 1.8 kg) than exercise training only, and a greater increase (p < or = 0.05) in maximal oxygen uptake (4.3 +/- 2.6 vs 1.9 +/- 2.0 ml/kg/min) versus dietary modification only. However, the reduction in BP with exercise training plus dietary modification (-12.5 +/- 6.3/7.9 +/- 4.3 mm Hg) did not differ significantly from that with exercise training only (-9.9 +/- 6.4/5.9 +/- 4.6 mm Hg) or dietary modification only (-11.3 +/- 12.1/7.5 +/- 4.3 mm Hg). These data indicate that the antihypertensive effects of exercise training and diet-induced weight loss are not additive. This finding has important public health and clinical implications for the millions of overweight persons with high normal BP or stage 1 or 2 hypertension.

Adult↗