Women who measure their peak heart rates for exercise will need to do some new math as will physicians giving stress tests to patients.
A new formula based on a large study from Northwestern Medicine provides a more accurate estimate of the peak heart rate a healthy woman should attain during exercise. It also will more accurately predict the risk of heart-related death during a stress test.
"Now we know for the first time what is normal for women, and it's a lower peak heart rate than for men," said Martha Gulati, M.D., assistant professor of medicine and preventive medicine and a cardiologist at Northwestern Medicine. "Using the standard formula, we were more likely to tell women they had a worse prognosis than they actually did."
Gulati is the lead author of a study published June 28 in the journal Circulation.
"Women are not small men," Gulati added. "There is a gender difference in exercise capacity a woman can achieve. Different physiologic responses can occur. " Gulati was the first to define the normal exercise capacity or fitness level for women in a 2005 study.
The old formula -- 220 minus age -- used for almost four decades, is based on studies of men. The new formula for women, based on the new research, is 206 minus 88 percent of age.
At age 50, the original formula gives a peak rate of 170 beats per minute for men and women. The new women's formula gives a maximum heart rate of 162 beats for women. Many men and women use their peak heart rate multiplied by 65 to 85 percent to determine their upper heart rate when exercising.
"Before, many women couldn't meet their target heart rate," Gulati said. "Now, with the new formula, they are actually meeting their age-defined heart rate."
The new formula is trickier to calculate, Gulati acknowledged, but is easily determined with a calculator. She currently is working on an iPhone application for a quick calculation.
The new formula is based on a study of 5,437 healthy women ages 35 and older who participated in the St. James Women Take Heart Project, which began in the Chicago area in 1992.
With the new formula, physicians will more accurately determine if women are having a normal or abnormal response to exercise. "If it's abnormal, that's a marker for a higher risk of death," Gulati said. "Maybe we need to talk about whether you exercise enough and what we need to do to get it into the normal range."
"We need to keep studying women to get data applicable to women," Gulati said. "It's important to not get complacent that we have data on men and assume women must be the same. They're not."
Gulati's senior author on the study was Morton Arnsdorf, M.D., professor emeritus and associate vice chairman of medicine and former section chief of cardiology at the University of Chicago. Arnsdorf died in a motor vehicle accident in June.
"I feel fortunate to have been his student, have him take me under his wing and be my mentor," Gulati said. "He was an amazing mentor." The Women Take Heart Project study had been sitting dormant, and Arnsdorf encouraged her to open it to do more research, Gulati said.
(Northwestern Medicine is comprised of Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital.)
Marla Paul is the health sciences editor. Contact her at firstname.lastname@example.org
Marla Paul | EurekAlert!
A promising target for kidney fibrosis
21.04.2017 | Brigham and Women's Hospital
Stem cell transplants: activating signal paths may protect from graft-versus-host disease
20.04.2017 | Technische Universität München
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy