Evidence continues to build that lifestyle modifications help control blood pressure (BP) levels. Data evaluating the consumption of coffee and alcohol and the impact of low fitness levels will be presented at the American Society of Hypertension, Inc.'s 26th Annual Scientific Meeting and Exposition (ASH 2011) and will be featured in the May 22 ASH press briefing.
"It's critical that we fully understand how lifestyle factors impact the ability of patients and physicians to screen, diagnosis, and treat high blood pressure," explains ASH press briefing moderator Lawrence J. Appel, MD, MPH, Professor of Medicine, Epidemiology and International Health (Human Nutrition) Director, Welch Center for Prevention, Epidemiology, and Clinical Research Johns Hopkins Medical Institutions. "As we continue to develop our understanding of how diet and exercise choices impact hypertension, including the nuances among specific patient populations, we are gathering evidence to help us best counsel and advise our patients."
Studies highlighted in the press briefing include:
Effect of Coffee on Blood Pressure and Cardiovascular Disease among Hypertensive Individuals: Meta-Analysis
Studies have shown that it is possible for caffeine to cause a short, but dramatic increase in your BP, even if you don't have high BP. A new meta-analysis shows that, among hypertensive individuals, caffeine intake of 1.5 - 2 cups produces an acute increase in BP, which lasts for at least three hours. However, present evidence does not support an association between longer-term coffee consumption and increased BP or increased risk of cardiovascular disease among patients with HBP.
In five trials, the administration of 200-300 mg caffeine (the content of 1.5-2 cups of filtered coffee) produced a mean increase of 8.2 mm Hg (95% confidence interval [IC] 6.2-10 mm Hg) in systolic BP and of 5.6 mm Hg (95% CI 4.2-6.9 mm Hg) in diastolic BP. The increase in BP was observed in the first hour after caffeine intake and lasted for at least three hours. In six trials on the longer-term effect (1 week) of coffee, there was no increase in BP when comparing caffeine versus placebo, coffee versus a caffeine-free diet, or coffee versus decaffeinated coffee.
"These results have clinical implications for the control of hypertensive patients. Because caffeine intake acutely increases blood pressure, hypertensive patients with uncontrolled blood pressure should avoid consuming large doses of caffeine. Also, the consumption of caffeine in the hours before measuring blood pressure may elevate the reading and give the erroneous impression that blood pressure is poorly controlled," explains lead study author, Esther Lopez-Garcia, PhD, Department of Preventive Medicine and Public Health, Autonoma University of Madrid, Spain. "Finally, in well-controlled hypertensive patients, there is no evidence to justify avoidance of habitual caffeine consumption and healthcare providers should emphasize other lifestyle modifications, such as maintaining weight control, increasing physical activity, and stopping smoking."
Alcohol Consumption and the Risk of Hypertension: A Systematic Review and Meta-Analysis. The Risk for Hypertension Increases Linearly with Alcohol Consumption in Men
Drinking too much alcohol can raise BP to unhealthy levels, especially among men. The meta-analysis evaluated a total of 16 prospective studies, which included 158,142 men and 314,258 women. Among men, a linear dose-response relationship between alcohol intake and risk of development of hypertension was noted. As compared to non-drinkers, men consuming < 10g/day of alcohol had a relative risk (RR) of 1.006, those consuming 10-20 g/day had a RR of 1.091, and those consuming > 30g/day had a RR of 1.416. Among women, the meta-analysis indicated protective effects at < 10g/day (RR -0.867) and 10-20g/day (RR - 0.904) of alcohol consumption, while the risk increased in women consuming > 30g/day (RR - 1.188). The risk of hypertension significantly increases with consumption of more than 30g/day in men in women alike.
"For patients, especially men, it's very important to ask about alcohol consumption and to recommend moderation when trying to maintain blood pressure control," explains Agarwal, MD, MPH, Department of Medicine, St. Luke's-Roosevelt Hospital, Columbia University College of Physicians and Surgeons.
Excessive Blood Pressure Elevation during Exercise Correlates with Low Fitness among Normotensive Firefighters. Lower Fitness is Associated with a Higher Risk of an Exaggerated Blood Pressure Response
Surprisingly, the leading cause of on- duty death among US firefighters (40% of cases) is coronary heart disease (CHD), rather than burns or smoke inhalation. The strain of suppressing a fire is associated with a markedly increased risk of cardiovascular mortality as compared to non-emergency duties and firefighters with low cardiorespiratory fitness are at increased risk for cardiovascular death. A study examined the prevalence of peak exercise hypertension among firefighters who do not have hypertension to see whether it correlates with low cardiorespiratory fitness.
The study evaluated 691 firefighters without hypertension and found that 14% (93) had an exaggerated BP response to exercise and 31.1% of the "exaggerated BP" firefighters were in a low fitness group, compared to 18% in the normal respondersexaggerated BP" group had high fitness (third quartile) compared to 30.6% in the normal responders.
"Firefighters present a unique opportunity to evaluate the role of fitness and its association with high blood pressure at peak exercise ," explains lead study author, Adi Leiba, MD, MHA, Fellow, Nephrology and Hypertension, Sheba Medical Center, Israel Clinical Instructor, Mount Auburn Hospital, Harvard Medical School, Boston, MA. "This data is important because it provides further evidence that improved fitness helps control blood pressure spikes, including those spikes during exercise and stress."
Genetic variants influence blood pressure from early in life