Research

by Ralph La Forge, MS on Mar 01, 2002

Impact of High-Normal Blood Pressure on CVD Risk; Computer-Tailored Smoking Cessation Program; Walking and High Blood Pressure

1. Impact of High-Normal Blood Pressure on CVD Risk

Vasan, R.S. et al. 2001. Impact of high-normal blood pressure on the risk of cardiovascular disease. New England Journal of Medicine, 345, 1291.

Study. Information is limited regarding the risk of cardiovascular disease in persons with high-normal blood pressure (BP) (resting systolic BP of 130-139 millimeters of mercury [mm Hg] and/or resting diastolic BP of 85-89 mm Hg). Investigators from the Framingham Heart Study in Framingham, Massachusetts, investigated the association between BP category at baseline and the incidence of cardiovascular disease (CVD) on follow-up among 6,859 study participants who were initially free of hypertension and CVD.

Vasan and colleagues noted a stepwise increase in cardiovascular event rates in persons who were in the higher BP categories at baseline. The 10-year cumulative incidence of CVD in subjects 35 to 64 years of age who had high-normal BP was 4 percent for women and 8 percent for men; in older subjects (those 65-90 years old), the incidence was 18 percent for women and 25 percent for men. Compared with optimal BP, high-normal BP was associated with hazard ratios for CVD of 2.5 (a 150% increase in risk) in women and 1.6 (a 60% increase in risk) in men. These ratios reflected adjustments for age, body mass index, smoking status, total cholesterol level and the presence or absence of diabetes mellitus.

The authors concluded that high-normal BP is associated with increased risk of CVD. They noted a need for more research to determine whether lowering high-normal BP can reduce CVD risk.

Comments. This study underscores the need to address those with high-normal BP, or what used to be thought of as “normal” BP. Adult clients who repeatedly have resting systolic BP of 130 to 139 mm Hg and/or resting diastolic BP of 85 to 89 mm Hg require lifestyle counseling. High-normal BP is quite responsive to moderate exercise (see the comments on the study by Moreau et al., page 18). For a complete and practical report on high BP and its treatment (JNC VI Guidelines for Evaluation, Treatment and Prevention of High Blood Pressure), contact the National Institutes of Health Web site at www.nhlbi.nih.gov/guidelines/hypertension/jncintro.htm.

2. Computer-Tailored Smoking Cessation Program

Etter, J.-F., & Perneger, T.V. 2001. Effectiveness of a computer-tailored smoking cessation program: A randomized trial. Archives of Internal Medicine, 161, 2596-601.

Study. From a public health perspective, prevention of cancer and CVD requires effective smoking cessation programs that can be implemented on a large scale. To test the effectiveness of a new computer-tailored smoking cessation program vs. no intervention, Etter and Perneger conducted a randomized, controlled trial in Switzerland between September 1998 and December 1999. Potential participants were randomly selected from a general population register and recruited by mail. Daily cigarette smokers who wished to participate (n = 2,934) were randomized to either the program or no intervention. Periodically, each participant in the active arm received by mail a computer-tailored counseling letter based on the participant’s answers to a questionnaire. Counseling letters were tailored to the subject’s level of tobacco dependence, self-efficacy, personal characteristics and current stage of change. Stages of change were categorized as precontemplation (has no intention of quitting smoking in the next 6 months), contemplation (is seriously considering quitting in the next 6 months) and preparation (has decided to quit in the next 30 days). Stage-matched smoking cessation booklets were sent with each counseling letter. The outcome measure was self-reported abstinence (no puff of tobacco smoke in the past 4 weeks) seven months after entry into the program.

Abstinence was 2.6 times greater in the intervention group than in the control group (5.8% vs. 2.2%, p < 0.001). Notably, the computer program was effective in “precontemplators,” who at baseline were not motivated to quit (intervention vs. control, 3.8% vs. 0.8%; p = .001) and was effective regardless of how difficult quitting seemed at baseline.

Consequently, Etter and Perneger determined that this program was effective in increasing smoking cessation rates. The authors observed that because the program can reach a large number of smokers, it has the potential to contribute substantially to disease prevention at a population level.

Comments. Although the absolute percentage of smokers who abstained from smoking after this program was small, the relative improvement in abstinence in the intervention group compared to the controls was quite remarkable. Since computerized smoking cessation programs are relatively easy to distribute and access, they can be very cost-effective. The American Lung Association, American Cancer Society and American Heart Association all have computerized materials to help smokers quit. The Internet also offers numerous sites—for example, www.QuitNet.com—designed to help smokers “quit and stay quit.”

3. Walking and High Blood Pressure

Moreau, K. L., et al. 2001. Increasing daily walking lowers blood pressure in postmenopausal women. Medicine & Science in Sports & Exercise, 33, 1825.

Study. The American College of Sports Medicine (ACSM) and the Centers for Disease Control and Prevention (CDC) recommend 30 minutes of daily, moderate-intensity physical activity for health; however, the effectiveness of this recommendation in lowering BP in hypertensive individuals is unclear. The present study tested the hypothesis that walking activity following the ACSM-CDC physical activity recommendation would lower BP in postmenopausal women with high BP (borderline to stage 1 hypertension). Twenty-four women took part in the study, which lasted 24 weeks. The 15 women in the exercise group walked three kilometers per day (1.9 miles) above their daily lifestyle walking, whereas the nine women in the control group did not change their activity level. Subjects in both groups self-measured their walking activity using a pedometer. Eight women in the exercise group and two controls were taking antihypertensive medicine; during the testing periods, these women took their medicine at the same time of day. Resting BP was measured in all the women at baseline, after 12 weeks and again after 24 weeks.

Among the exercisers, resting systolic BP dropped 6 mm Hg (p < 0.005) by the 12-week mark and a further 5 mm Hg (p < 0.005) by the end of 24 weeks. Walking brought about no change in diastolic BP. The controls registered no change in BP at either 12 or 24 weeks. During the 24 weeks, body mass decreased modestly in the exercise group (-1.3 kilograms) (p < 0.05); however, this drop was not correlated with the change in BP. Body mass did not drop among the controls. Neither group showed a significant change in percent body fat, fasting plasma insulin or dietary intake—all variables known to impact BP.

Moreau and colleagues concluded that a 24-week walking program meeting the ACSM-CDC physical activity recommendation is effective in lowering systolic BP in postmenopausal women with borderline to stage 1 hypertension.

Comments. One of this study’s important findings was that in the exercise group, BP decreased by similar amounts in the women taking antihypertensive medicine as it did in the women not taking medication. This is unusual. Some past research found that exercise caused no further reductions in BP in subjects who were already receiving antihypertensive medication.

Nearly 60 million adults in the United States have hypertension. Of these people, 80 percent have stage 1 hypertension, like the women in this study. Past research has shown that unlike other cardiovascular risk factors, such as blood cholesterol, stage 1 hypertension (including high- normal BP) is relatively easy to manage with exercise. What’s more, there is growing scientific consensus that regular, moderate exercise (40%-60% of maximum aerobic capacity) is at least as efficacious in this regard as vigorous exercise. Assisting clients with stage 1 hypertension therefore represents a most worthy opportunity for fitness professionals.

IDEA Health Fitness Source, Volume 2003, Issue 3

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About the Author

Ralph La Forge, MS

Ralph La Forge, MS IDEA Author/Presenter

Ralph La Forge, MS, is a physiologist and board-certified clinical lipid specialist. He is the managing director of the cholesterol disorder physician education program at Duke University Division of Endocrinology, Metabolism and Nutrition in Durham, North Carolina. He is also a physiologist at the U.S. Indian Health Service Division of Diabetes Treatment and Prevention in Albuquerque and Santa Fe NM. He is currently President of the American Council on Clinical Lipidology (National Lipid Association). He has multiple consulting agreements with biotech firms and health care organizations throughout North America.