People who drink at a least one cup of coffee to start their morning may not know how it is affecting the cardiovascular system. A normal blood pressure is considered less than 120/80 mm Hg. Chronic readings greater than 140/90 mmHg will mark you as hypertensive. Certain decisions you make each day, particularly concerning caffeine and exercise, can affect your blood pressure.
Blood Pressure and Caffeine
Acutely, caffeine increases blood pressure. According to the American Heart Association, the effect of dietary caffeine on blood pressure should be taken more seriously. According to a study published in "Hypertension" in 2000, by Terry R. Hartley and colleagues the effects of caffeine on hypertensive men may be damaging. The study took 182 male participants, 73 with optimal blood pressure, 28 with normal blood pressures, 36 with high-normal and 27 diagnosed with hypertension. Upon administraton of caffeine, all blood pressure levels elevated. The hypertensive group's blood pressure increased 1.5 times greater than the optimal blood pressure group. Interestingly, 78 percent of the hypertensive-diagnosed men became hypertensive and 4 percent of stage one men became hypertensive as well. This study clearly indicates that caffeine increases blood pressure and may be dangerous if you are already diagnosed with high blood pressure.
Blood Pressure and Exercise
When you exert yourself physically, your heart must make changes in order to keep up with the increased demand for blood by your working muscles. Increases in heart rate and blood pressure are necessary to accommodate changes in blood flow. Systolic blood pressure rises consistently with the intensity of exercise. However, diastolic blood pressure is left unchanged or may even decrease. Regular exercise is beneficial to your cardiovascular system. Changes including decreased heart rate, increased blood volume and heart size and contractility all result in a lower resting blood pressure.
The Effects of Caffeine and Exercise on Blood Pressure
For some, exercising while on caffeine can wreck havoc on your cardiovascular system. Both caffeine and physical activity increase your blood pressure, caution should be taken when exercising after caffeine consumption. Caffeine raises both systolic and diastolic blood pressures alike. During exercise, diastolic pressure lessens due to the decrease in total peripheral resistance around the heart from dialation of arteries. Caffeine can counteract this effect, making blood flow around the body difficult for the heart to overcome. According to the American College of Sports Medicine, you should not exercise if your blood pressure is greater than or equal to 200/110 mmHg at rest.
Considerations
There is evidence that believes caffeine is beneficial to ingest before exercise. According to Dr. Michael Colgan, author of "Optimum Sports Nutrition," intake of caffeine by an athlete before competition or hard training can boost performance. Caffeine can work to decrease fatigue by increasing your lactate threshold and fatty acid mobilization. However, if you are not a trained athlete and do suffer from hypertension, be cautious when drinking caffeine before exercise.
References
- American Heart Association: High Blood Pressure
- American Heart Association Journals: Hypertension Risk Status and Effect of Caffeine on Blood Pressure
- "Exercise Testing and Prescription"; David C. Nieman; 2007
- "Exercise Physiology"; George A. Brooks, Thomas D. Fahey, Kenneth M. Baldwin; 2005
- "ACSM's Guidelines for Exercise Testing and Prescription" Whaley, Mithcell H., PhD, Brubaker, Peter H., Phd, Otto, Robert M., Phd (Eds.). 2006
- "Optimum Sports Nutrition"; Dr. Michael Colgan; 1993
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