I know it sucks (especially for coffee drinders, but you'd better know :
NEW YORK (Reuters Health) - People who consume caffeine may experience an increase in blood pressure, feel more stressed and produce more stress hormones than on days when they opt for decaf, US researchers report.
Furthermore, Dr. James D. Lane and his colleagues at Duke University in Durham, North Carolina found that the effects of caffeine appear to persist until people go to bed, even if they don't consume any caffeine after 1 p.m.
Given the long-lasting effects of caffeine, the authors suggest that regular consumption of the substance could contribute to the risk of developing heart disease. Furthermore, Lane told Reuters Health that any condition influenced by stress could also be aggravated by caffeine.
For example, in people with the type 2 form of diabetes--often associated with obesity--stress can worsen the condition by influencing how well the body regulates blood sugar, Lane said. He added that people with stress-related disorders, such as post-traumatic stress disorder or social anxiety, could also experience adverse effects from caffeine consumption.
"Any stress-related disease could be aggravated by caffeine," Lane said.
In the US, approximately 85% of adults drink caffeine every day, in the form of coffee, soft drinks, or tea.
In the current study, the participants--47 regular coffee drinkers--consumed 500 milligrams of caffeine, in the form of two pills. This quantity of caffeine is roughly equivalent to that contained in 4 small (8 ounce) cups of coffee. The second pill was taken no later than 1 pm. Each participant took caffeine pills during one workday, and inactive pills during another workday, and frequently recorded how stressed they felt. The participants never knew whether the pills contained caffeine ora placebo.
The researchers monitored the participants' blood pressure, heart rate, and the quantity of certain substances they excreted in their urine.
Reporting in the July/August issue of Psychosomatic Medicine, Lane and his colleagues found that people had slightly higher blood pressure levels, produced 32% more of the stress hormone epinephrine, and felt more stressed on days when they took a caffeine-containing pill compared to the days they took the placebo.
In an interview with Reuters Health, Lane said that the effects of caffeine likely persist in the body because the substance takes a long time to deteriorate. More specifically, caffeine has a "half-life" of an average of 4 hours, meaning that however much caffeine you consume, it will take your body 4 hours to rid itself of half that amount. And 4 hours later, your body will contain only one-quarter of the original amount. Consequently, 12 hours after consuming caffeine, Lane explained, your body still contains one-eighth of what you first drank.
Lane added that he hesitates to tell people exactly how much caffeine they should consume each day. However, for those with conditions that are aggravated by stress, or have high blood pressure, "one simple thing they can try is to cut back on caffeine," he said, and see if that helps alleviate their symptoms.
Cutting out caffeine "doesn't cost a thing, and it may make you feel better. So it's worth a try," Lane advised.
SOURCE: Psychosomatic Medicine 2002;64:593-603.
NEW YORK (Reuters Health) - People who consume caffeine may experience an increase in blood pressure, feel more stressed and produce more stress hormones than on days when they opt for decaf, US researchers report.
Furthermore, Dr. James D. Lane and his colleagues at Duke University in Durham, North Carolina found that the effects of caffeine appear to persist until people go to bed, even if they don't consume any caffeine after 1 p.m.
Given the long-lasting effects of caffeine, the authors suggest that regular consumption of the substance could contribute to the risk of developing heart disease. Furthermore, Lane told Reuters Health that any condition influenced by stress could also be aggravated by caffeine.
For example, in people with the type 2 form of diabetes--often associated with obesity--stress can worsen the condition by influencing how well the body regulates blood sugar, Lane said. He added that people with stress-related disorders, such as post-traumatic stress disorder or social anxiety, could also experience adverse effects from caffeine consumption.
"Any stress-related disease could be aggravated by caffeine," Lane said.
In the US, approximately 85% of adults drink caffeine every day, in the form of coffee, soft drinks, or tea.
In the current study, the participants--47 regular coffee drinkers--consumed 500 milligrams of caffeine, in the form of two pills. This quantity of caffeine is roughly equivalent to that contained in 4 small (8 ounce) cups of coffee. The second pill was taken no later than 1 pm. Each participant took caffeine pills during one workday, and inactive pills during another workday, and frequently recorded how stressed they felt. The participants never knew whether the pills contained caffeine ora placebo.
The researchers monitored the participants' blood pressure, heart rate, and the quantity of certain substances they excreted in their urine.
Reporting in the July/August issue of Psychosomatic Medicine, Lane and his colleagues found that people had slightly higher blood pressure levels, produced 32% more of the stress hormone epinephrine, and felt more stressed on days when they took a caffeine-containing pill compared to the days they took the placebo.
In an interview with Reuters Health, Lane said that the effects of caffeine likely persist in the body because the substance takes a long time to deteriorate. More specifically, caffeine has a "half-life" of an average of 4 hours, meaning that however much caffeine you consume, it will take your body 4 hours to rid itself of half that amount. And 4 hours later, your body will contain only one-quarter of the original amount. Consequently, 12 hours after consuming caffeine, Lane explained, your body still contains one-eighth of what you first drank.
Lane added that he hesitates to tell people exactly how much caffeine they should consume each day. However, for those with conditions that are aggravated by stress, or have high blood pressure, "one simple thing they can try is to cut back on caffeine," he said, and see if that helps alleviate their symptoms.
Cutting out caffeine "doesn't cost a thing, and it may make you feel better. So it's worth a try," Lane advised.
SOURCE: Psychosomatic Medicine 2002;64:593-603.