Is Having Had a Cup of Coffee a Methodological Issue in Routine Sphygmomanometry?
Nyunt Wai *
Department of Human Biology, School of Medical Sciences, International Medical University (IMU), 126, Jalan Jalil Perkasa 19 Bukit Jalil, 57000 Kuala Lumpur, Malaysia.
Mohd Ariff Bin Khaled
Sem.7 B. Pharm. Student, School of Pharmacy, International Medical University (IMU), Bukit Jalil, 57000 Kuala Lumpur, Malaysia.
Archana Singh Sikarwar
Department of Human Biology, School of Medical Sciences, International Medical University (IMU), 126, Jalan Jalil Perkasa 19 Bukit Jalil, 57000 Kuala Lumpur, Malaysia.
*Author to whom correspondence should be addressed.
Abstract
Background: In view of the impact of hypertension on public health, the objective of this study was to determine whether having had a cup of coffee in an everyday life setting raises blood pressure significant enough to make it a methodological issue in routine sphygmomanometry.
Methods: Healthy normotensive volunteers from a private university in Malaysia were recruited. After an overnight fast, seated systolic and diastolic blood pressures (SBP and DBP) of habitual coffee drinkers (n=16) were measured (Omron HEM 7080 automated monitor) in the laboratory 15 min. before and every 15 min. up to 90 min. after drinking strong coffee. This was repeated on non-habitual drinkers (n=16) who also underwent a control study (decaffeinated coffee). To see whether the laboratory findings could be extrapolated to everyday life setting, the pre-coffee BP and 30 min.- and 60 min.- post-coffee BPs were measured on habitual coffee drinkers (n=18) who consumed self-prepared coffee and who carried on with routine office work between BP measurements taken in a nearby room.
Results: In the laboratory setting, coffee significantly increased SBP and DBP at all time-points in non-habitual drinkers (e.g.11.38+/- 8.2 and 10.75+/-5.7 mm Hg at 75 min; P<0.01, repeated measures ANOVA and Dunnett's test); in habitual drinkers, SBP only was increased (7.23+/-4.7 at 90 min; P<0.05). In the office setting, smaller but significant DBP elevations (3.72+/-5.1 at 60 min; P<0.05) were observed.
Conclusion: The results indicate that having had a cup of coffee could be a methodological issue in routine sphygmomanometry, particularly with non-habitual coffee drinkers consuming strong coffee. However, caution should be exercised in drawing conclusions because of the small sample size.
Keywords: Caffeinated coffee, decaffeinated coffee, blood pressure, methodological issue, sphygmomanometry, habitual coffee drinker, non-habitual coffee drinker, office setting.