Hypertension develops disproportionately among African Americans compared with non-Hispanic Caucasian and Mexican Americans, with the greatest relative disparity in incidence occurring at younger ages.1,2 African-American women had the greatest increase from 1988 to 2000 in hypertension prevalence compared with other sex and race/ethnic groups in the recent National Health and Nutrition Examination Survey data.2 Correlates of hypertension incidence include both physical inactivity and obesity. Of concern for African-American women are low levels of physical activity3-5 combined with high rates of obesity.6 Recently, the Nurses' Health Study found that physical inactivity and obesity contributed independently to the development of coronary heart disease in women.7 These conditions contribute to the increased risk for coronary heart disease whether or not they precede the development of hypertension.
The ideal profile type, intensity, and duration of physical activity to best achieve optimal outcomes among hypertension-prone African-American women remain unclear given that physical activity must be feasible for, and acceptable to, the target population. Although current federal guidelines recommend at least 30 minutes of moderate-intensity activity on most, preferably all days of the week (either as one sustained session or broken up over the course of the day),8,9 nearly 30% of African-American women are physically inactive.4,5Healthy People 2010 Initiatives underscore the priority of reducing minority health disparities,10 emphasizing the need for interventions to promote health-enhancing behaviors that are unique and culturally sensitive. Women often have multiple responsibilities such as work, household chores, and family, and these barriers can deter them from routinely engaging in physical activity. Lack of time is a common reason for not being physically active.11-13 For individuals who do not have enough time to exercise continuously over a long period (or session), the issue of engaging in multiple short bouts of activity (lifestyle physical activity [LPA]) may be particularly attractive and more convenient. If such an exercise strategy was shown to provide cardiovascular benefits, the public health potential would be substantial.
Therefore, the purpose of this tailored intervention was to examine the blood pressure (BP) effects of integrating LPA into the daily routine of hypertension-prone, sedentary African-American women aged 18 to 45 years. Lifestyle physical activity is the accumulation of at least 30 minutes of self-selected activities (including leisure, occupational, or household activities) performed at a level of moderate intensity, which may be planned or unplanned, and incorporated as part of every day life.14 Lifestyle physical activity allows greater flexibility with regard to selecting physical activity time (eg, when to incorporate physical activity into the day) and type (eg, whether activity is continuous or accumulative). A home-based model of physical activity is advantageous given women's general preference to be physically active on one's own after some instruction.12
This randomized, parallel-group, single-blind clinical trial was conducted between September 2002 and July 2004 at Rush University Medical Center in Chicago, Ill. Participants were randomized to 1 of 2 groups: (1) Exercise or (2) No Exercise. The trial was conducted in 2 contiguous phases: (1) prerandomization visits (3 weeks of screening) and (2) follow-up clinic visits (8 weeks of intervention) (Figure 1). The primary intervention was an 8-week individualized, home-based, physical activity program consisting of LPA. The institutional review board approved the study protocol, and each participant provided written informed consent.
The target population consisted of generally healthy, US-born African-American women, aged 18 to 45 years who had high-normal (130-139/85-89 mm Hg) or untreated stage 1 hypertension (140-159/90-99 mm Hg) as defined by the Joint National Committee (JNC VI) guidelines.15 Eligibility criteria included not taking antihypertensive medication, sedentary lifestyle, premenopausal status, and BP in the prespecified range based on the average of 2 of 3 screening visits. Exclusion criteria were use of antihypertensive drugs or other medication that affects BP, smoking, anemia, pregnancy, postmenopausal status, actively dieting or participating in a weight loss program, and known cardiovascular or pulmonary disease requiring treatment. A variety of recruiting strategies, including BP screenings, health fairs, physician referral, flyers, and advertisements, were used for potential candidates during a 19-month period.16
Three screening visits (lasting ∼30 minutes) were used to establish BP status, perform a physical examination, and obtain a complete blood count. A maximal Bruce Protocol exercise test was performed at the third screening visit to determine exercise safety and to prescribe a training heart rate. Eligible participants were randomly assigned, with equal probability to (1) Exercise or (2) No Exercise via computer-generated, random-numbers table. Before randomization, baseline measures of BP, 24-hour ambulatory BP, self-reported physical activity, and weight/height were obtained. Clinic staff obtaining BP measurements were blinded to group assignment. After randomization, participants were seen in the clinic every 2 weeks for BP and weight measurements (visits lasting 20-30 minutes), and 24-hour ambulatory BP monitoring was obtained on the day before the last scheduled clinic visit. Participants were asked not to alter their dietary habits during the course of the study.
Participants randomized to Exercise were instructed to engage in LPA (eg, walking, stair climbing) for 10 minutes, 3 times a day, 5 days a week, at a prescribed heart rate corresponding to an intensity of 50% to 60% heart rate reserve. The goal of the intervention was to accumulate 150 minutes of physical activity per week. Before starting LPA, participants received a private education session lasting approximately 60 minutes. Key topics reviewed during this session included (1) health benefits of LPA, (2) safety issues, (3) goal setting and self-monitoring, (4) identifying physical activity barriers and developing strategies to overcome them, (5) identifying simple ways to incorporate activity into daily living, and (6)creating ways to individualize physical activity. Women were instructed to keep a log documenting physical activity mode, frequency, duration, and heart rate. In addition, participants were shown how to use and wear a portable heart rate monitor. The main focus during the education session was to identify ways to easily incorporate physical activity into daily living.
The intervention was tailored to meet the unique characteristics of each individual. Women were encouraged to increase their physical activity while being aware of daily conflicts between caregiving and work responsibilities, as well as managing other daily stressors. Behavior change strategies focused on empowering women to find a balance between their "self-care" and caring for others. Participants were encouraged to select modes of physical activities that were enjoyable and easily incorporated into daily schedules (walking, climbing stairs, dancing, gardening). For example, taking stairs rather than waiting for the elevator, walking to the store rather than driving, getting off the bus several blocks before the designated stop to walk, getting up to move during TV commercials, and spending half a lunch break walking rather than sitting around. The purpose of the intervention was not to add more stress to the lives of these busy women, but rather to find simple ways to incorporate physical activity into daily living by making physical activity habits as routine as brushing teeth and combing hair.
At biweekly clinic visits, key topics from the education manual were reinforced. This allowed time for participants to identify pressing issues, review goals, address barriers, solve problems, and develop strategies for overcoming barriers to attain physical activity goals. Physical activity logs were reviewed biweekly; variations from the prescribed amount of physical activity were discussed with participants, and alternative strategies were implemented if necessary. For example, if a participant was having difficulty accumulating 30 min/d because of child care responsibilities, it was suggested to select activities that can be done with children, such as dancing, hula hoop, walking, or jump roping, with the intent of reaching the prescribed target heart rate.
Women randomized to the No Exercise group were instructed to continue with their usual daily activities. Activity logs and heart rate monitors were not used with the No Exercise group because it is possible that attention to physical activity would affect behavior.
Resting Cuff BP
Resting BP was measured with a calibrated mercury sphygmomanometer following the American Heart Association recommendations.17 Participants were requested not to ingest caffeine within 30 minutes before measurement. During BP measurements, participants were seated in an upright chair with feet flat on the floor. For consistency, the same sphygmomanometer, with an appropriately sized attachable cuff, was used, and research nurses taking blinded BP measurements underwent periodic test-retest procedures to verify reliability and accuracy of BP techniques. Three pressure readings were recorded within a 5-minute period using the average of these readings as that visit's measurement. Resting BP was measured 24 hours after the last bout of physical activity to avoid acute effects of physical activity. To evaluate the effects of LPA, BP was measured before randomization and at weeks 2, 4, 6, and 8.
Ambulatory BP Monitoring
Twenty-four-hour ambulatory BP was obtained using a SpaceLabs monitor (SpaceLabs Model 90207; SpaceLabs, Redmond, Wash) with well-established reliability and validity18-20 to determine the influence of LPA on pressure load indices. Ambulatory BP was measured using oscillometric methods every 15 minutes during daytime hours and every 60 minutes during nighttime hours. The pressure transducer channel was automatically zeroed before each reading. Daytime-nighttime differences were determined by self-reported wake-sleep times. Participants were given the ambulatory BP monitor before randomization and at their final clinic visit at week 8. They were shown how to use the monitor, maintain proper arm placement, record a diary, and instructed to wear it on the day before their scheduled visit. Ambulatory BP was monitored 24 hours after the last bout of physical activity to avoid acute effects of physical activity.
Weight and Body Mass Index
Weight, height, and calculations for body mass index (BMI) were obtained following Pollock and Wilmore guidelines.21 Weight was measured to the nearest 0.1 kg using a platform balance-beam scale with participants in underclothing and without shoes. Height was measured using a flat vertical surface and measured to the nearest 0.5 cm. Body mass index was calculated using the formula, weight (in kilograms)/height2 (in meters). Body weight was measured before randomization and at weeks 2, 4, 6, and 8 to correspond with BP measurements. Body mass index was determined before randomization.
Self-report Physical Activity
The Yale Physical Activity Survey assesses adults' physical activity patterns via 3 indicators (total time, total energy expenditure, and total activity summary index) of physical activity reflecting activities performed in a typical week of the previous month.22 The survey includes vigorous, recreational, and work-related activities, many of which are commonly done by women (eg, food preparation and gardening). Eight indices are derived, and physical activity participation is expressed in hours and kilocalories per week. Reliability and validity of the tool have been confirmed, and activity dimensions positively correlated with physiological variables.22 The Yale Physical Activity Survey was interviewer administered (requiring ∼10 minutes) during the second eligibility visit to assess sedentary physical activity status (an inclusion criterion). The Yale Physical Activity Survey was repeated at weeks 4 and 8 to assess any changes in self-reported physical activity, especially among the No Exercise group.
Self-reported Physical Activity Logs
Exercise group participants completed daily physical activity logs documenting mode, frequency, and duration of physical activity and the heart rate at midsession. These logs were reviewed during biweekly visits (weeks 2, 4, 6, and 8). Variation from the prescribed physical activity was discussed with the participant to develop alternative strategies for achieving desired goals. The logs were used as a self-monitoring technique and to verify training workload and adherence.
Polar Heart Rate Monitors
On 2 occasions, participants in the Exercise group were monitored at home with heart rate recorders consisting of a microprocessor/receiver wristwatch and midtorso elastic belt transmitter that stores 99 files of data or up to 9,999 hours (Polar S610; Polar Electro Inc, Port Washington, NY). The heart rate monitor data were compared with the physical activity logs to verify self-reported physical activity intensity, duration, and frequency.
Adherence to the prescribed physical activity regimen is difficult to evaluate without direct observation; therefore, adherence was determined by several complementary methods: (1) self-reports of physical activity frequency (ie, number of bouts or activity sessions, the participant reported/number of prescribed bouts of activity), (2) self-reports of physical activity duration (ie, total minutes of participant-reported physical activity/prescribed minutes of activity), (3) quantification of physical activity intensity (ie, the average heart rate recorded by the Polar S610 monitor during each bout of physical activity, expressed as a percentage of peak heart rate/the average-prescribed training heart rate), and (4) quantification of physical activity duration (ie, the duration of each bout of physical activity documented on the Polar S610 monitor/the duration of the self-reported bout of physical activity). Several home-based exercise intervention studies have successfully used self-reported activity logs (alone and in combination with portable monitors) to evaluate exercise adherence.23-25 The monitor recordings provided objective data to corroborate the participants' physical activity logs.
Statistical Considerations and Analyses
The study was designed to have an 80% power for detecting and effect size of d = 126 for cuff BP using 2-sided, paired t test with a 0.05 significance level. Our intent was to determine whether this effect size could be generalized to a population of African-American women. Demographic characteristics were tabulated by group using descriptive statistics or frequency distributions where appropriate. Clinical outcomes (weight, BP) were examined to ensure normal distribution. Changes from baseline for continuous variables were determined by subtracting week 8 levels from baseline levels. The average change from baseline in cuff BP, ambulatory BP indices, and weight were tested using paired t tests. Independent-samples t tests were used to assess differences between groups for clinical outcomes. Adherence to the prescribed physical activity was analyzed using percentages. Relationships between BP change and physical activity adherence were examined using Pearson correlation and scatterplot. Analyses were performed on an intention-to-treat basis. All analyses were performed using SPSS version 10.1 (SPSS, Chicago, Ill).
There were 136 inquiries during the 19-month recruiting period as previously reported.16 Thirty-five women (26%) were eligible for the initial screening, and 24 (18%) were enrolled into the study. Table 1 shows demographic characteristics for the study sample. The average age was 39 ± 5.5 years with some college education. Half of the women were single (50%); the majority worked full time (71%) and had child care and work responsibilities (42%), and most were involved in community service activities (79%). Postrandomization retention rate was 96%; 1 participant dropped out because of work-related issues.
Table 2 provides baseline characteristics by group. There were no differences at randomization between groups for age, BMI, or BP. Women in both groups had systolic BP (SBP) in the prehypertensive range but were classified as having stage 1 hypertension by virtue of their diastolic BP (DBP).27 Although BMI was not used as a study entry criterion, it is interesting to note that the average BMI was 36.5 kg/m2, and therefore, most of these women were classified as obese according to current guidelines.28
Table 3 shows mean preintervention and postintervention BP levels by group. The Exercise group had a significant reduction in SBP (−6.4 mm Hg, P = .036) and a reduction in DBP (−3.3 mm Hg), as shown in Figure 2. These changes were independent of any significant changes in weight. Although the change in DBP for the Exercise group did not reach statistical significance, BP status changed from stage 1 hypertension to prehypertension, which corresponds to an effect size of 0.76 (Figure 3) These BP changes are comparable to those reported in recent meta-analytic reviews examining the effects of physical activity on BP in hypertensive subjects, which consisted mostly of caucasian men.29-31 The No Exercise group had a nonsignificant decrease in SBP and increase in DBP (−5.0 and +2.5 mm Hg, respectively).
Overall, ambulatory BP did not change significantly in either group, but greater changes were noted for nighttime pressure load in the Exercise group (systolic, 9%; diastolic, 25%) compared with the No Exercise group (systolic, 7%; diastolic, 10%), as shown in Table 4. Pressure load, defined as the percentage of daytime readings of more than 140/90 mm Hg and nighttime readings of more than 120/80 mm Hg,32 is a better predictor of target organ damage than cuff BP.33-36 Previous data have shown that African Americans have an attenuated nocturnal decline in BP and greater evidence of early target organ damage compared with caucasians.37-41 For our sample of young, hypertension-prone African-American women, pressure load may well be the best measure of potential target organ damage42,43 and therefore clinically important.
Parameters of physical activity adherence ranged from 65% to 98% as presented in Figure 4. In addition to keeping self-reported logs, participants in the Exercise group used Polar heart rate monitors on 2 separate occasions for a 2-week period to coincide with biweekly clinic visits. Exercise participants were instructed to maintain physical activity logs throughout the study period, which was successfully achieved 91% of the time. In addition, the goal for the heart rate monitors was to obtain 30 evaluable files over the study period, which was successfully achieved 60% of the time. Self-reported frequency (recorded activity/amount prescribed) was 72%. Self-reported duration (recorded time in minutes/amount prescribed) was 87%. Heart rate intensity (percentage of peak heart rate/average-prescribed training heart rate) was 65%. Monitored duration (duration documented on monitor/self-reported duration) was 98%. These data are comparable to adherence rates observed in other physical activity intervention studies involving women.44-48 Adherence data were corroborated by a significant correlation between change in SBP and physical activity duration (r = −0.620, P = .024), suggesting that women who adhered to the prescribed physical activity minutes had greater change in SBP (Figure 5). Adherence was further corroborated by the significant increase in self-reported energy expenditure in the Exercise compared with the No Exercise group (P = .047), which was maintained throughout the study period, as shown in Figure 6.
Our study was designed specifically to examine the BP responses of LPA among young, hypertension-prone African-American women, a group about whom less information is available than either Caucasian women or older African-American women.29,49 We observed several interesting findings concerning the BP effects and adherence to LPA.
The favorable change in BP status from stage 1 hypertension to prehypertension with LPA is of clinical importance. Diastolic BP typically elevates during younger adult years and tends to plateau after the fifth decade of life, whereas SBP increases progressively with age.1 Consequently, DBP-related hypertension is more problematic for younger adults. Therefore, the BP reductions we observed are of sufficient magnitude to be clinically relevant.
Several prospective studies have demonstrated favorable health outcomes with moderate physical activity13,23,25,50-56; however, few have provided data concerning effects of physical activity on young, hypertension-prone African-American women. We are aware of only 3 pretest-posttest-design, exercise-training studies focusing solely on black hypertensive women, none of which used randomization or control group (Nigerian and African American).57-59 In addition, these studies included women who already had hypertension rather than women at risk for developing hypertension, which might overestimate the intervention effect because of regression to the mean. Furthermore, neither of these studies used 24-hour ambulatory BP monitoring, known to be a more sensitive marker for target organ damage.60,61 The study involving Nigerian women57 showed statistically significant reductions in SBP and DBP with exercise. Although the second study58 showed a trend toward a reduction in SBP and DBP, these changes were not statistically significant. In this latter study, the 1-week exercise period may have been too short to evoke maximal BP-lowering effects. The 12-month study59 involving untreated and treated hypertensive African-American women was designed to promote walking (increasing steps) and did not focus on, or report, BP-related outcomes (personal communication with JoAnne Banks-Wallace, August 4, 2006), therefore limiting the ability to determine BP effects of the intervention. Importantly, all 3 of these studies involved middle-aged women and may not generalize well to younger women, who may have different characteristics and personal needs than older women.
Our second notable finding pertains to the reduction in nighttime pressure load. The operational threshold for pressure load is less than 15%,32 indicating that our sample of women had pressure loads well above the norm. The study was powered for a change in cuff BP and not ambulatory BP, but ambulatory BP may be a particularly good measure of potential organ damage, at least in this population. Therefore, the improved nighttime pressure load we observed may be clinically given the strong correlation between pressure load and target organ damage.62 Only a few small studies have examined the effects of physical activity on ambulatory BP,63-66 and less is known about these effects among women,67,68 especially young, hypertension-prone African-American women. Data from 2 cross-sectional studies involving normotensive caucasian women showed lower 24-hour BP variability and pressure loads among endurance-trained women compared with sedentary women.67,68 These data are limited because of their cross-sectional design and inability to generalize well to our population of young, hypertension-prone African-American women. Data from 2 other cross-sectional studies69,70 examined the effects of physical activity on ambulatory BP in hypertensives and showed improved ambulatory BP levels for physically active men69 and women70 compared with those who are less active. Ambulatory BP provides a more comprehensive assessment of BP and cardiovascular risk; thus, these studies provide important information concerning hypertension-prone individuals. However, the absence of data in minority women limits the ability to generalize these results to young, hypertension-prone African-American women.
Our third finding of interest is the surprisingly high adherence to LPA (self-reported frequency and duration, heart rate monitor-recorded intensity and duration) given the fact that participants had multiple family and work responsibilities. Few physical activity intervention studies have included meaningful numbers of African-American women; therefore, what is currently known regarding adherence rates is based predominately on middle-aged caucasian women.71 Our findings suggest that LPA is feasible in our population. The 72% self-reported frequency and 87% self-reported duration indicates that, overall, women were able to accumulate physical activity throughout the day and sustain it for the prescribed duration. However, maintaining heart rate at the prescribed intensity was challenging, given the 65% adherence rate. These data suggest that women were able to be physically active but not always at the desired intensity. Given the fact that we were encouraging LPA (ie, incorporating activity into daily living), it seems that reaching the prescribed intensity was not always as easy as achieving the desired frequency and duration of physical activity. These data differ somewhat from our observation using a similar activity protocol in postmenopausal women72 who maintained heart rate intensity at a much greater rate. This may, in part, be due to the fact that most women in our previous study were not working, nor did they have child care responsibilities. In addition, the 98% duration rate using heart rate monitor versus self-report confirms that women were, in fact, physically active as reported. Lastly, participant motivation may have contributed to the high rates of LPA adherence we observed.
Random treatment assignment, blinded clinical outcome measures, and tailoring of the intervention underscore the strength of our study; however, there are several potential limitations to our findings. The sample size is small and limited to young, hypertension-prone African-American women, making it difficult to generalize our findings to other populations. The small sample size also makes it difficult to perform multivariate analyses on our data. The 8-week intervention is short and needs to be replicated with longer-term follow-up. Although we corroborated self-reported physical activity with the use of portable heart rate monitors, more precision, in terms of physical activity outcomes, could have been obtained by adding a postintervention exercise stress test to measure cardiorespiratory fitness. Lastly, 4 participants were unable to successfully wear the 24-hour ambulatory monitor because of improper cuff fitting (as a result of large arm circumference and fat distribution).
This is the first study to test the feasibility and efficacy of a tailored intervention incorporating LPA in young, hypertension-prone African-American women. Our current study builds upon the few known LPA interventions previously conducted in older caucasian men and women.51,52 Our study also builds upon the recommendations for tailoring behavior change interventions to meet culture-specific,73-75 sex-specific,76,77 and age-specific71 needs of the target population, something that is not routinely considered when designing clinical trials involving special populations. Importantly, because our participants did not alter their diet or have changes in weight during the study period, we were able to evaluate the incremental benefit of LPA without confounding alterations in weight. We have shown that LPA can be applied to young, hypertension-prone African-American women with cultural appropriateness and feasibility of replication and that this intervention can lead to measurable decreases in BP indices within a relatively short period. An important public health challenge is to motivate individuals who are hypertension-prone to make healthy lifestyle changes. Findings from this study will add to the knowledge about the most effective ways for preventing hypertension and promoting healthy lifestyles among this hypertension-prone population.
1. Burt VL, Whelton R, Rocella EJ, et al. Prevalence of hypertension
in the US adult population: results from the Third National Health and Nutrition Examination Survey, 1998-1991. Hypertension
2. Hajjar I, Kotchen TA. Trends in prevalence, awareness, treatment, and control of hypertension
in the United States, 1988-2000. JAMA
3. Crespo C, Keteyian S, Heath G, Sempos C. Leisure-time physical activity among US adults: results from the third national health and nutrition examination survey. Arch Intern Med
6. Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in obesity among US adults, 1999-2000. JAMA
7. Li TY, Rana JS, Manson JE, et al. Obesity as compared with physical activity in predicting risk of coronary heart disease in women. Circulation
8. US Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General
. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion; 1996.
9. Pate RR, Pratt M, Blair SN, et al. Physical activity and public health. JAMA
11. Eyler AA, Baker E, Cromer L, King AC, Brownson RC, Donatelle RJ. Physical activity and minority women: a qualitative study. Health Educ Behav
12. King AC, Castro CM, Wilcox S, et al. Personal and environmental barriers to physical activity among US born minority women ages 40 years and older. Health Psychol
13. Wilbur J, Vassalo A, Chandler P, McDevitt J, Micheals Miller A. Midlife women's adherence to home-based walking during maintenance. Nurs Res
14. Dunn AL, Andersen RE, Jakicic JM. Lifestyle physical activity
interventions. History, short- and long-term effects, and recommendations. Am J Prev Med
15. The Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. The Sixth Report of the Joint Committee on Prevention, Detection, Evaluation, and the Treatment of High Blood Pressure (JNC VI). Arch Intern Med
16. Staffileno BA, Coke L. Recruiting and retaining young, sedentary, hypertension
-prone African-American women
for a physical activity intervention study. J Cardiovasc Nurs
17. Pickering TG, Hall JE, Appel LJ, et al. Recommendation for blood pressure measurement in humans and experimental animals. Part 1: blood pressure measurement in humans. Hypertension
18. O'Brien E, Waeber B, Parati G, et al. Blood pressure measuring devices: recommendations of the European Society of Hypertension
19. Amoore JN, Dewar D, Gough K, Padfield PL. Do SpaceLabs ambulatory non-invasive blood pressure recorders measure blood pressure consistently over several years use? Blood Press Monit
20. Pang TCY, Brown MA. Accuracy of ambulatory blood pressure monitors in routine clinical practice. Am J Hypertens
21. Pollock M, Wilmore J. Exercise in Health and Disease
, 2nd ed. Philadelphia: WB Saunders; 1990.
22. Diepetro L, Casperson C, Ostfeld A, Nadel E. A survey for assessing physical activity among older adults. Med Sci Sports Exerc
23. Debusk R, Stenestrand U, Sheehan M, Haskell W. Training effects of long versus short bouts of exercise in health subjects. Am J Cardiol
24. Gossard D, Haskell W, Taylor C, et al. Effects of low- and high-intensity home-based exercise training on functional capacity in healthy middle-aged men. Am J Cardiol
25. King AC, Haskell WL, Young D, Oka RK, Stefanick ML. Long-term effects of varying intensities and formats of physical activity on participation rates, fitness and lipoproteins in men and women aged 50 to 60 years. Med Sci Sports Exerc
26. Cohen J. Statistical Power Analysis for the Behavioral Sciences
. New Jersey: Lawrence Erlbaum Associates; 1988.
27. Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA
29. Dickinson HO, Mason JM, Nicolson DJ, et al. Lifestyle interventions to reduce blood pressure: a systematic review of randomized controlled trials. J Hypertens
30. Whelton SP, Chin A, Xin X, He J. Effect of aerobic exercise on blood pressure: a meta-analysis of randomized, controlled trials. Ann Intern Med
31. Bacon SL, Sherwood A, Hinderliter A, Blumenthal JA. Effects of exercise, diet and weight loss on high blood pressure. Sports Med
32. Ernst ME, Bergus GR. Ambulatory blood pressure monitoring. South Med J
33. White WB. How well does ambulatory blood pressure predict target-organ disease and clinical outcomes in patients with hypertension
? Blood Press Monit
. 1999;4 (suppl 2):S17-S21.
34. Clement DL, De Buyzere ML, De Bacquer DA, et al. Prognostic value of ambulatory blood pressure recordings in patients with treated hypertension
. N Engl J Med
35. Mancia G, Parati G, Castiglioni P, et al. Daily life blood pressure changes are steeper in hypertensive than in normotensive subjects. Hypertension
36. Mancia G, Facchetti R, Bombelli M, Grassi G, Sega R. Long-term risk of mortality associated with selective and combined elevation in office, home, and ambulatory blood pressure. Hypertension
37. Flack JM, Cardin JM, Yunis C, Liu K, for the CARDIA Research Group. Static and pulsatile blood pressure correlates of left ventricular structure and function in black and white adults: the CARDIA study. Am Heart J
38. Gottdiener JS, Reda DJ, Materson BJ, et al. Importance of obesity, race and age to the cardiac structural and functional effects of hypertension
. Am J Cardiol
39. Mayet J, Shahi M, Foale RA, Poulter NR, Sever PS, Thom SA. Racial differences in cardiac structure and function in essential hypertension
40. Sherwood A, Hughes JW, McFetridge J. Ethnic differences in the hemodynamic mechanisms of ambulatory blood pressure regulation. Am J Hypertens
41. Hinderliter AL, Blumenthal JA, Waugh R, Chilukuri M, Sherwood A. Ethnic differences in left ventricular structure: relations to hemodynamics and diurnal blood pressure variation. Am J Hypertens
42. Profant J, Dimsdale JE. Race and diurnal blood pressure patterns. A review and meta-analysis. Hypertension
43. Verhecchia P, Schillaci G, Guerrieri M, et al. Circadian blood pressure changes and left ventricular hypertrophy in essential hypertension
44. Snyder KA, Donnelly JE, Jabosen DJ, Hertner G, Jakicic JM. The effects of long-term, moderate intensity, intermittent exercise on aerobic capacity, body composition, blood lipids, insulin and glucose in overweight females. Int J Obes
45. Jakicic JM, Winters C, Lang W, Wing RR. Effects of intermittent exercise and use of home exercise equipment on adherence, weight loss, and fitness in overweight women: a randomized trial. JAMA
46. King AC, Baumann K, O'Sullivan P, et al. Effects of moderate-intensity exercise on physiological, behavioral, and emotional responses to family caregiving: a randomized controlled trial. J Gerontol
47. Castro CM, Wilcox S, O'Sullivan P, Baumann K, King AC. An exercise program for women who are caring for relatives with dementia. Psychosom Med
48. Wilbur J, Michaels Miller A, Chandler P, McDevitt J. Determinants of physical activity and adherence to a 24-week home-based walking program in African American and Caucasian women. Res Nurs Health
49. Kelly GA, Sharpe-Kelly K. Aerobic exercise and resting blood pressure in women: a meta-analytic review of controlled clinical trials. J Womens Health Gend-Based Med
50. Ebisu T. Splitting the distance of endurance running: on cardiovascular endurance and blood lipids. Jpn J Phys Educ
51. Dunn AL, Marcus BH, Kampert JB, Carcia ME, Kohl HW, Blair SN. Comparison of lifestyle and structured interventions to increase physical activity and cardiorespiratory fitness. JAMA
52. Andersen RE, Wadden TA, Barlett SJ, Zemel B, Verde TJ, Franckowiak SC. Effects of lifestyle activity vs structured aerobic exercise in obese women. JAMA
53. Murphy MH, Hardman AE. Training effects of short and long bouts of brisk walking in sedentary woman. Med Sci Sports Exerc
54. Moreau KL, Degarmo R, Langley J, et al. Increasing daily walking lowers blood pressure in postmenopausal women. Med Sci Sports Exerc
55. Nies MA, Chruscial HL, Hepworth JT. An intervention to promote walking in sedentary women in the community. Am J Health Behav
56. Elmer PJ, Grimm R Jr, Laing B, et al. Lifestyle intervention: results of the Treatment of Mild Hypertension
Study (TOMHS). Prev Med
57. Oluseye KA. Cardiovascular responses to exercise in Nigerian women. J Hum Hypertens
58. Brown MD, Moore GE, Korythowski MT, McCole SD, Hagberg JM. Improvement of insulin sensitivity by short-term exercise training in hypertensive African American women. Hypertension
59. Banks-Wallace J, Enyart J, Johnson C. Recruitment and entrance of participants into a physical activity intervention for hypertensive African-American women
. Adv Nurs Sci
60. White WB. Ambulatory blood pressure and target organ involvement in hypertension
. Clin Invest Med
61. Wallace JP, Bogle PG, King BA, Drasnoff JB, Jastremski CA. A comparison of 24-h average blood pressure and blood pressure load following exercise. Am J Hypertens
62. Staessen JA, Thijis L, Fagard R, et al. Predicting cardiovascular risk using conventional vs ambulatory blood pressure in older patients with systolic hypertension
63. Blumenthal JA, Siegal WC, Appelbaum M. Failure to exercise to reduce blood pressure in patients with mild hypertension
64. Seals DR, Reiling MJ. Effect of regular exercise on 24-hour arterial pressure in older hypertensive humans. Hypertension
65. Somers VK, Conway J, Johnston J, Sleight P. Effects of endurance training on baroreflex sensitivity and blood pressure in borderline hypertension
66. Zanettini R, Bettega D, Agostoni O, et al. Exercise training in mild hypertension
: effects on blood pressure, left ventricular mass and coagulation factor VII and fibrinogen. Cardiology
67. Seals DR, Silverman HG, Reiling MJ, Davy KP. Effect of regular aerobic exercise on elevated blood pressure in postmenopausal women. Am J Cardiol
68. Seals DR, Stevenson ET, Jones PP, DeSouza CA, Tanaka H. Lack of age-associated elevations in 24-h systolic and pulse pressure in women who exercise regularly. Heart Circ Physiol
69. Kokkinos P, Pittaras A, Manolis A, et al. Exercise capacity and 24-h blood pressure in prehypertensive men and women. Am J Hypertens
70. Palatini P, Granier GR, Mormino P, et al. Relation between physical training and ambulatory blood pressure in stage I hypertensive subjects: results of the HARVEST trial. Circulation
71. Krummel DA, Matson Koffman D, Bronner Y, et al. Cardiovascular health interventions in women: what works? J Womens Health Gend-Based Med
72. Staffileno BA, Braun LT, Rosenson RS. The accumulative effects of physical activity in hypertensive, post-menopausal women. J Cardiovasc Risk
73. Yancy AK, McCarthy WJ, Harrison GG, et al. Challenges in improving fitness: results of a community-based, randomized, controlled lifestyle change intervention. J Womens Health
74. Scisney-Matlock M, Glazewki L, McCkerking C, Kachorek L. Development and evaluation of DASH diet tailored messages for hypertension
treatment. Appl Nurs Res
75. Kumanyika SK, Shults J, Fassbender J, et al. Outpatient weight management in African-Americans: the Healthy Eating and Lifestyle Program (HELP) study. Prev Med
76. Karanja N, Stevens VJ, Hollis JF, Kumanyika SK. Steps to soulful living (steps): a weight loss program for African-American women
. Ethn Dis
77. Yanek LR, Becker DM, Moy TF. Project Joy: faith based cardiovascular health promotion for African American women. Public Health Rep
. 2001;116 suppl:68-81.