Is Caffeine Bad for Your Heart?
New Research Suggests Caffeine Elevates Blood Pressure, Stress
The total caffeine given equaled that found in four cups of coffee, and the capsules were consumed in the morning and at lunchtime. Blood pressure and heart rate were measured repeatedly on both days using a portable monitor, and stress hormone levels were monitored through urine samples.
When caffeine and placebo days were compared, the researchers found blood pressure to be consistently higher on the caffeine days -- an average of 4 millimeters (mm) higher for systolic pressure and 3 mm for diastolic. Stress hormone levels also rose by an average of 32% on the caffeine days, and both the blood pressure and adrenaline increase lasted throughout the day and into the evening.
"The message for the average coffee drinker is that if they are worried about blood pressure or if they feel highly stressed, they might want to consider cutting back on or eliminating caffeine," Lane says. "It is a simple thing to do, and they might feel a whole lot better."
But giving up her daily caffeine fix doesn't sound simple to Liebswager. She says previous attempts to cut back on coffee have left her feeling muddleheaded, irritable, and fatigued.
Lane says caffeine withdrawal symptoms can be minimized if people cut back gradually.
"Regular coffee drinkers who can't get going in the morning without that shot of caffeine are probably already in withdrawal," he says. "Sleepiness, mental fogginess, and not being able to concentrate are all symptoms of caffeine withdrawal. So when they get past those withdrawal symptoms they may find that they feel much better without caffeine."