PHYSICAL FITNESS FAVORABLY MODIFIES HEMOSTATIC RISK FACTORS

Bo Fernhall, PhD; Linda M. Szynanski; Craig M. Kessler; Exercise Science Department, Syracuse University and Hematology Research Laboratory, Georgetown University Medical Center

Recent data questions the cardioprotective effects of hormone replacement therapy (HRT) in postmenopausal women; thus, alternatives to modify risk factors are needed. This cross-sectional study evaluated physical exercise as an option by comparing hemostatic profiles in 48 healthy postmenopausal women (mean age = 57.5 years), categorized by fitness and HRT user status into 4 groups (n = 12 per group): unfit nonusers, fit nonusers, unfit users, and fit users. Tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) activities and antigens in addition to prothrombin fragment 1+2 (F1+2) were determined at rest and after maximal treadmill exercise (see Table).

Table. No caption available.TPA is expressed as IU/mL and PAI-1 as AU/mL

Higher tPA and lower PAI-1 activities were seen in HRT users and fit groups (P < .05) and fit groups showed greater changes with exercise (P < .05). tPA and PAI-1 antigens were lower in HRT and fit groups (P < .05), but not after correction for BMI. F1+2 was lower in the fit groups (P < .05), regardless of HRT status. Fibrinogen was similar in all groups. Favorable hemostatic profiles were observed in physically fit compared to unfit women, especially in HRT nonusers. Regular exercise may be a viable option to modify hemostatic risk factors in postmenopausal women, particularly those unable or unwilling to take HRT.

MODULATION OF OXYGEN UPTAKE KINETICS BY MYOCARDIAL ISCHEMIA DURING EXERCISE

Hitoshi Adachi, MD; Norimichi Koitabashi, MD; Takuji Toyama, MD; Shigeto Naito, MD; Hiroshi Hoshizaki, MD; Shigeru Oshima, MD; Koichi Taniguchi, MD; Gunma Prefectural Cardiovascular Center

Rational and Objectives:

Myocardial ischemia is known to reduce the cardiac contractility. It is assumed that the degree of cardiac dysfunction depends on the extent of myocardial ischemia. Because cardiac function is one of the major regulating factors of oxygen uptake kinetics during exercise, diminishment of cardiac function would affect on the oxygen uptake kinetics. However, it is not well observed how myocardial ischemia influences on the kinetics of oxygen uptake during exercise. Therefore, we investigated the effect of myocardial ischemia on oxygen uptake kinetics.

Methods:

Twenty-three patients with known coronary arteriosclerosis were assigned into two groups according to the coronary lesion site. Patients whose coronary lesion was located at the proximal site in the coronary artery were assigned into group A (n = 10, age 58.3 years). Those with distal lesion were into group B (n = 13, age 61.2 years). Cardiopulmonary exercise testing (CPET) was performed to assess the oxygen uptake kinetics.

Results:

All patients showed the significant ST depression during CPET. There was no difference in severity of lesion stenosis between two groups (86.7% vs 83.8%). Culprit lesions of groups A and B were as follows: group A #6 (n = 4), #1 (n = 4), and #11 (n = 2); group B #7 (n = 5), #8 (n = 1), diagonal branch (n = 6), and #4 AV (n = 1) in AHA classification. There was no significant difference in peak oxygen uptake between two groups (19.2 vs 19.2 mL/min/kg). DVO₂/DWR before the onset of myocardial ischemia was not different between two groups (group A: 8.0 +/- 1.0 mL/watt, group B: 8.6 +/- 2.3). When it was compared after the onset of myocardial ischemia, it was smaller (P = .018) in group A (6.2 +/- 2.5) than that in group B.

Conclusion:

These data indicate that the oxygen uptake kinetics during exercise is depressed when myocardial ischemia occurs in patients with broad myocardial ischemia.

INTENSITY THRESHOLD FOR POSTEXERCISE HYPOTENSION

Carl Foster; Christy Smelker; Margaret A. Maher; Ray Martinez; John P. Porcari; University of Wisconsin-La Crosse

Hypertension is a modifiable risk factor for heart disease. Acute exercise causes a reduction in blood pressure for several hours following the exercise bout, referred to as postexercise hypotension (PEH). The magnitude of the exercise stimulus necessary to produce PEH is not established. This study evaluated the effects of different intensities of exercise on PEH in mild hypertension. Subjects (n = 10) were apparently healthy, mildly hypertensive individuals. Each subject completed four randomly ordered 120-minute trials (involving 25 minutes of exercise between 0 and 30 minutes) and one 120-minute control (eg, nonexercising) trail. The four trials consisted of cycle ergometer exercise at intensities of 70%, 80%, 90%, and 100% of the VO₂ at the ventilatory threshold (VT) (eg, ranging from quite easy to rather hard). BP was measured at 0, 30, 60, 90, and 120 minutes of each trial. The data were analyzed with repeated-measures ANOVA. There was a significant reduction in SBP at 30, 60, 90, and 120 minutes for 100% VT, at 60, 90, and 120 minutes for 90% VT, at 90 and 120 minutes for 80% VT, and at 120 minutes for 70% VT. There was no significant change in DBP. Mean BP was significantly reduced at 120 minutes for 70% VT, at 60, 90, and 120 minutes for 90% VT, and at 90 minutes for 100% VT. We conclude that exercise can lower BP in mildly hypertensive individuals and that a higher intensity exercise session may have a greater effect on PEH.

DEVELOPMENT AND EVALUATION OF PHYSICAL FITNESS FIELD TESTS FOR ADULTS AGED 55 TO 75 YEARS

Carrie Ritchie, PhD; Dr Stewart Trost; Prof Wendy Brown; University of Queensland

Rationale:

Decreases in balance, strength, and functional capacity occur with age and can be improved with appropriate physical activity. Valid and reliable laboratory tests exist that assess these factors, and results can help guide recommendations for physical activity and provide incentives for continuation. However, these tests are costly, time-consuming, and require appropriately trained assessors. Hence, access to these tests is limited.

Objectives:

The purpose of this study was to develop and evaluate field tests to assess balance, strength, and functional capacity that were valid, reliable, time efficient, cost effective, and easy to administer. Valid and reliable field tests already exist that measure other factors such as flexibility and body composition.

Methods:

Twenty-two subjects aged 55 to 75 years participated in three testing sessions. Two field test sessions were completed 7 days apart and included: assessment of balance, 60 seconds lift and reach (eg, upper body strength), 60 s sit to stand (eg, lower body strength), multiple level step test (eg, functional capacity), and a single timed chair rise (eg, rate of force development). A single laboratory session included: changes to center of gravity using a force platform (eg, balance), one repetition maximum (1RM) bench press (eg, upper body strength), 1RM leg press (eg, lower body strength), submaximal bicycle ergometer test (eg, functional capacity), and a timed plyopower squat (eg, rate of force development).

Results:

Intraclass correlation showed good reliability for the lift and reach (R = 0.87), sit to stand (R = 0.84), and step tests (R = 0.92), and not the balance (-) and single timed chair rise (R = -.28). Pearson correlation showed a significant correlation for the sit to stand and 1RM leg press (P < .05), and the step test and PWC 140/kg (P < .001). The lift and reach and 1RM bench press approached signficance.

Conclusion:

Some of the field tests evaluated were shown to be valid and reliable. These tests were inexpensive, easy to administer, and required a short amount of time (eg, approximately 20 minutes total). These types of tests may be useful in settings such as outpatient cardiac rehabilitation, secondary prevention programs, community activity programs, GP programs, and rural programs seeking measures of physical function in older adults.

LEFT VENTRICULAR GEOMETRIC PATTERN IS ASSOCIATED WITH EXERCISE CAPACITY IN PATIENTS WITH HYPERTENSION.

Lee M. Pierson; Simon L. Bacon; Michael R. Santise; Elizabeth D. Gullette; Andrew Sherwood; Alan L. Hinderliter; Robert Waugh; James A. Blumenthal Duke University Medical Center

Rationale:

Previous research has shown that hypertensive patients with left ventricular hypertrophy (LVH) have an impaired exercise tolerance. LVH may exist as concentric or eccentric hypertrophy, as defined by relative wall thickness of the left ventricle (RWT), with distinct clinical and functional consequences.

Objectives:

The purpose of this study was to determine the relationship between left ventricular geometry and exercise capacity in unmedicated, hypertensive patients.

Methods:

Eighty-nine, sedentary, overweight men (n = 39) and women (n = 50) with high normal blood pressure or stage 1 to 2 hypertension participated. An echocardiogram determined LVH and RWT. LVH was defined as LV mass index > 53.9 kg/m^2.7, while high RWT was defined as a ratio of septal plus posterior wall thickness to end-diastolic diameter > 0.50. Patients were divided into groups based on cardiac geometry: concentric hypertrophy (LVH with high RWT, n = 12); concentric remodeling (no LVH with high RWT, n = 12); eccentric hypertrophy (LVH with low RWT, n = 19); and normal geometry (no LVH with low RWT, n = 46). To determine exercise capacity, peak oxygen consumption (VO₂) was measured during a maximal exercise treadmill test. ANCOVA, with Newman-Keuls post hoc analysis, was used to test for geometry group differences in peak VO₂, with gender and age as covariates.

Results:

Analysis of the data revealed a significant main effect for geometry (F = 3.60, P < .02). Peak VO₂ (mL/kg/min) for concentric hypertrophy (corrected mean +/- SE = 23.6 +/- 1.2) was significantly lower (P < .05) than the concentric remodeling (27.6 +/- 1.2) and normal (27.4 +/- 0.6) geometries. Peak VO₂ among patients with eccentric hypertrophy (25.4 +/- 0.9) was not different from any other group.

Conclusion:

Left ventricular geometric pattern was found to be associated with exercise capacity in unmedicated, hypertensive patients. Individuals with concentric hypertrophy showed reduced capacity when compared to those with concentric remodeling or normal geometry.

BLOOD PRESSURE DURING SUBMAXIMAL EXERCISE IS ASSOCIATED WITH LEFT VENTRICULAR RELATIVE WALL THICKNESS IN OVERWEIGHT, MILDLY HYPERTENSIVE PATIENTS

Lee M. Pierson; Simon L. Bacon; Michael R. Santise; Elizabeth D. Gullette; Andrew Sherwood; Alan L. Hinderliter; Robert Waugh; James A. Blumenthal; Duke University Medical Center

Rationale:

Studies of left ventricular hypertrophy (LVH) and exercise systolic blood pressure (SBP) have produced inconsistent results. Failure to consider relative wall thickness, which allows distinction between eccentric and concentric hypertrophy, and lack of adjustment for covariates such as age, resting SBP, or body mass index (BMI), may help to explain these varied results found in the literature.

Objective:

This study examined the relationship of exercise SBP and left ventricular geometry in a sample of overweight, mildly hypertensive volunteers.

Methods:

Eighty patients (43 women) with unmedicated high normal blood pressure or stage 1 to 2 hypertension participated. An echocardiogram determined left ventricular mass and wall thickness relative to end-diastolic chamber dimension. Criterion for LVH was defined as a LV mass index > 53.9 kg/m^2.7. Patients were considered to have high relative wall thickness (RWT) if their ratio was > 0.50. LVH was diagnosed in 26 patients, while 20 met criterion for high RWT. Subjects performed a maximal graded exercise test with SBP recorded at rest and workloads of 2, 4, and 6 METs. Repeated measures ANCOVA tested for group SBP differences at submaximal workloads, with resting SBP, age, gender, and BMI as covariates.

Results:

ANCOVA revealed a main effect for RWT group (F = 6.85, P = .01); high RWT had greater submaximal SBP compared with low RWT. Post-hoc analyses revealed significant SBP differences at 2 METS (high vs low, mean +/- SE, 193 +/- 4.1 vs 180 +/- 2.7), 4 METS (198 +/- 4.0 vs 187 +/- 2.6), and 6 METS (209 +/- 4.2 vs 198 +/- 2.8). There was no main effect found for LVH (F = 0.59, P = ns).

Conclusion:

SBP responses to submaximal exercise are associated with RWT, but are not related to the presence of LVH, in overweight hypertensive patients; those with greater RWT exhibiting larger SBP responses.