Blood pressure during exercise

Changes of blood pressure during acute exercise and possible effects of endurance training on a chronically increased blood pressure.

Blood pressure is the pressure of the blood in the heart and arteries. The term “blood pressure” usually refers to the force on arterial walls, exerted by the circulating blood. This is why the arterial system is called “high-pressure-system”. This system is responsible for transporting oxygenated blood towards all organs of the body. The level of blood pressure is basically determined by blood volume, cardiac output, and peripheral resistance in blood vessels. Blood pressure is usually expressed by two numbers, for example 120/80. The former is the systolic pressure that is build up during cardiac contraction whereas the latter relates to the pressure during the diastolic phase of the cardiac cycle.

Well defined ranges of resting blood pressure, that shouldn’t be exceeded, are available.
The current classification of the JNC (Joint National Comitee on Detection, Education, and treatment of High Blood Pressure) additionally includes some advices of necessary stage dependent procedures that should be followed (1). To reduce situational influences on blood pressure, measurements should be performed three times in a row with a break of 5 min on three consecutive days.

During exercise, systolic blood pressure rises. Values up to 190-220mmHg are considered to be normal (2). By contrast, systolic blood pressure during exercise above this threshold refers to exercise hypertension. Some studies provide evidence that this kind of hypertension predicts future resting hypertension (3;4).

Even though the peripheral resistance is reduced (1/3 of resting level), the blood flow rises disproportionately (by factor of 3 in untrained and factor 5 in trained subjects), causing a increased systolic blood pressure. The observable drop of diastolic values, measured with a blood pressure cuff, must be considered as an artifact (5). The actual rise of the diastolic blood pressure can only be detected, using invasive methods like a heart catheter.



A study of Kokkinos et al. (6), showed that regular exercise in addition to antihypertensive medication significantly reduced diastolic blood pressure and left ventricular hypertrophy in African-American men with severe hypertension: One half of the recruited subjects were randomly assigned to the training group (exercise + antihypertensive medication), whereas the other half only received the antihypertensive medication without working out. Training consisted of three training sessions a week, each 45min at 75% of the maximum heart rate. After 16 weeks of training, the intervention group presented decreased blood pressure levels and a reduced thickness of the interventricular septum, compared to the control group. The effects remained significant after 32 weeks of exercise, even with reduction of antihypertensive medication.

Conclusion: Endurance training is capable to reduce blood pressure during exercise, patho-morpholical changes of the heart, and the needed dose of antihypertensive medication. Therefore endurance training can be considered as a multipotent preventative measure in high blood pressure patients. The accompanied reduction of body fat may also contribute to the positive effects. Rule of thumb: Every kg body weight that is lost, is usually accompanied by a drop of blood pressure for round about 2mmHg]

Recommendation: Patients suffering from arterial hypertension should perform a low intensity endurance training, after consulting a physician. Dynamic exercises at constant workloads, seem to be particular suitable. By contrast, high performance sports and high intensive resistance training sessions should be avoided, as they are associated with unfavorable blood pressure peaks. Particularly, breath-holding during resistance exercises are problematic, as they increases intra-thoracic pressure (5).




Reference List

(1) Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL, Jr. et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA 2003; 289(19):2560-2572.
(2) Tzemos N, Lim PO, MacDonald TM. Is exercise blood pressure a marker of vascular endothelial function? QJM 2002; 95(7):423-429.
(3) Dlin RA, Hanne N, Silverberg DS, Bar-Or O. Follow-up of normotensive men with exaggerated blood pressure response to exercise. Am Heart J 1983; 106(2):316-320.
(4) Wilson NV, Meyer BM. Early prediction of hypertension using exercise blood pressure. Prev Med 1981; 10(1):62-68.
(5) Hollmann W, Hettinger T, Strueder H. Sportmedizin. Grundlagen für Arbeit, Training und Präventivmedizin. 4 ed. Stuttgart: Schattauer Verlagsgesellschaft mbH; 2000.
(6) Kokkinos PF, Narayan P, Colleran JA, Pittaras A, Notargiacomo A, Reda D et al. Effects of regular exercise on blood pressure and left ventricular hypertrophy in African-American men with severe hypertension. N Engl J Med 1995; 333(22):1462-1467.