Studies Indicate Lifestyle Variations Affect Hypertension

Evidence continues to build that lifestyle modifications help control blood pressure levels. Data evaluating the consumption of coffee and alcohol and the impact of low fitness levels were presented at the American Society of Hypertension’s 26th Annual Scientific Meeting and Exposition.

Studies have shown that it is possible for caffeine to cause a short but dramatic increase in blood pressure, even if someone has not been diagnosed with high blood pressure. A new meta-analysis shows that among hypertensive individuals, caffeine intake of 1.5 to 2 cups produces an acute increase in blood pressure that lasts for at least three hours. However, present evidence does not support an association between longer-term coffee consumption and increased blood pressure or an increased risk of cardiovascular disease among patients with high blood pressure.

In five trials, the administration of 200 to 300 mg of caffeine (the content of 1.5 to 2 cups of filtered coffee) produced a mean increase of 8.2 mm Hg in systolic blood pressure and of 5.6 mm Hg in diastolic blood pressure. The increase in blood pressure was observed in the first hour after caffeine intake and lasted for at least three hours. In six trials on the longer-term (one week) effect of coffee, there was no increase in blood pressure when comparing caffeine vs. placebo, coffee vs. a caffeine-free diet, or coffee vs. decaffeinated coffee.

Another study looked at alcohol overconsumption causing blood pressure to rise 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 the risk of developing hypertension was noted. Compared with nondrinkers, men consuming fewer than 10 g/day of alcohol had a relative risk (RR) of 1.006; those consuming 10 to 20 g/day had a RR of 1.091; and those consuming more than 30 g/day had a RR of 1.416.

Among women, the meta-analysis indicated protective effects at fewer than 10 g/day (RR = 0.867) and 10 to 20 g/day (RR = 0.904) of alcohol consumed, while the risk increased in women consuming more than 30 g/day (RR = 1.188). The risk of hypertension significantly increases with the consumption of more than 30 g/day of alcohol in men in women alike.

The final study looked at the leading cause of on-duty death among U.S. firefighters (40% of cases): coronary heart disease. The strain of suppressing a fire is associated with a markedly increased risk of cardiovascular mortality compared with nonemergency duties, and firefighters with low cardiorespiratory fitness are at increased risk of cardiovascular death. A study examined the prevalence of peak exercise hypertension among firefighters without 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 blood pressure response to exercise and 31.1% of the firefighters were in a low-fitness group compared with 18% of the normal responders. Only 13.5% of the exaggerated blood pressure group had high fitness levels compared with 30.6% of the normal responders. Thus, lower fitness is associated with a higher risk of an exaggerated blood pressure response.

Source: American Society of Hypertension