Source:-runnersworld.com
Oftentimes, a high systolic blood pressure (the top number) can indicate poor heart health, but does the same hold true when your blood pressure spikes due to exercise?
To answer this question, researchers at Stanford looked at stress test results taken both at rest and at peak exercise of 7,500 men collected over the course of 20 years and compared them to their mortality rates.
The study, which was published in the European Journal of Preventive Cardiology, found that high systolic blood pressure during exercise may not necessarily indicate that a person is at risk for heart disease—as long as workload, or intensity, is taken into account.
Current guidelines from the American Heart Association define an exaggerated systolic blood pressure (SBP) response to exercise as a peak SBP of 210 millimeters of mercury (mmHg) in males and 190 mmHg in females. These high blood pressure (BP) levels are often interpreted to show increased risk of heart disease.
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However, in this study, researchers found that higher the peak systolic blood pressure during treadmill testing, better the health prognosis of the individual. Meaning, that people reaching a higher SBP value lived longer than those with low SBP at peak exercise.
Why? Physiologically, systolic blood pressure rises with rising workload (like during a treadmill or bicycle stress test), Kristofer Hedman, Ph.D., physician at Linkoping University in Sweden told Runner’s World. People who are fitter—which is related to higher survival rates—are usually able to reach higher workloads, spiking their BP higher.
Especially in well-trained athletes, achieving high workloads also means a high blood pressure reading at peak exercise, well above current thresholds. In well-trained athletes, performing close to 20 METs (running at 13 mph, or a 4.6-minute mile), it is not uncommon to see SBP values around 250 mmHg, but for an unfit individual, that would be a high SBP reading, as they might reach only 6 to 7 METs (a slow jog), explained Hedman.
Unless the reading is extremely high—a value over 260–270 mmHg would probably never be considered “normal”—it is likely not indicative of anything else than a high fitness level, as long as the test is normal in all other aspects, Hedman said. These would include the heart rate response, the electrocardiogram (ECG), and/or symptoms such as chest pain, excessive dyspnea (labored breathing), and nausea.
“So, if you have a great fitness, you will achieve a high workload, thus probably a higher systolic BP, and have a better prognosis,” said Hedman.
On the flip side, though, higher SBP alone doesn’t mean better fitness. Rather, in healthy people, rising SBP will follow rising METs.
This shows that it’s important for physicians to take workload into account, rather than just looking at the blood pressure reading when interpreting results of things like stress tests. Higher systolic blood pressure in a person at a high workload—say, sprinting—is not as troubling as a high SP in a person reaching a low workload, like at an easy jog.
“An important contribution of our work is that we show that accounting for workload is probably more appropriate and should be considered in all cases,” Hedman said. “This is largely neglected today.