Weightlifting can make women feel more energetic and lower inflammation—all while maintaining the integrity of the body’s blood-brain interface, according to a new study from the University of Georgia.
Led by post-doctoral researcher David Diggs and kinesiology professor Patrick O’Connor in the Mary Frances Early College of Education, the study focused on how high-intensity resistance exercise, specifically weightlifting, impacts mood, inflammation, and brain health in both trained and untrained women.
The brain during exercise
As an indicator of blood-brain interface integrity or how well the brain’s protective filter is working to maintain a stable environment, researchers measured levels of the protein S100β in 37 women who completed a 45-minute high-intensity, full-body weightlifting session.
Researchers collected saliva samples before the session, directly after, and again 24 hours later to measure the S100β protein.
“Our well controlled experiment showed that a single bout of high intensity resistance exercise does not increase S100β in healthy young adult women,” said O’Connor. “This implies that the blood-brain interface is still doing what it should do, which is to keep things that are supposed to stay in the brain, in the brain, and to block potentially harmful molecules that might cause problems out of the brain.”
Earlier studies found increases in S100β after exercise; however, many involved physical activities in extreme environments, such as scuba diving or high-altitude hiking, which can raise S100β levels for other reasons. These studies suggest that exercise might make the blood-brain interface temporarily “leaky.”
However, when environmental changes and other factors—such as potential head impacts from sports like soccer and boxing were eliminated—Diggs and O’Connor found no change in S100β, indicating that leakiness is not a problem. Their findings are consistent with other evidence suggesting that a single bout of exercise has brain health benefits.
“If you just exercise without these factors, then exercise alone does not change saliva levels of this brain protein,” said O’Connor. “Removing the extraneous variables allowed us to conduct a more conclusive and scientifically supportable study of exercise per se compared to previous ones.”
The study also found that while inflammation, indexed by the C-reactive protein (CRP), increased slightly immediately following exercise, it returned to pre-exercise levels 30 minutes later. Untrained women also displayed higher inflammation levels compared to trained women before exercise, as well as 24 hours after exercise.
“If you train regularly, then your body adapts, and you end up having overall less inflammation,” said O’Connor. “Many people have some inflammation chronically, but exercise has anti-inflammatory properties if you do it regularly. So, we found that in this case, too, the trained women showed lower CRP, which is generally interpreted as a good thing for health.”
In the mood for exercise
In addition to experiencing lower inflammation, trained women also reported higher vigor or energy levels than untrained women.
“Immediately following exercise, vigor improved for both trained and untrained women, but there wasn’t a significant change on some of the other measures for mood such as anger,” said Diggs, who is completing his post-doctoral research at the University of Alabama at Birmingham. “Generally speaking, trained females also showed less depression and less confusion.”
While most past research on resistance exercise has focused on men, this study adds new evidence that women can safely and effectively benefit from strength training—both physically and mentally.
“I hope that research into resistance exercise can remove barriers and make it more accessible,” said Diggs. “Obviously, some of these things are hot topics across social media, but I think if women want to pursue better health, and we also remove some of the stigmas about resistance exercise, we can reduce hesitance for vigorous resistance exercise through scientifically supported information.”
The study also offers a new approach to encourage more women to try strength training—not by focusing on long-term health benefits, but on how it makes people feel immediately.
“For years, people have tried to get others to exercise by listing all the ways it’s good for you—you’ll get stronger, you might lose weight,” explained O’Connor. “But that approach hasn’t really worked, because it’s not like everyone’s working out now that we know all the benefits.”
Instead, O’Connor suggests a different message: focus on how exercise makes the individual feel.
“If you do it, you’ll feel better,” he said. “This study shows that even a single bout of exercise can make women feel more energetic, which is a positive thing. That might be a better reason for some people to give it a try and even keep with it.”
Published in “Physiology & Behavior,” the study was co-authored by Alison Bamford and Elizabeth Thomas from the Institute for Interdisciplinary Salivary Bioscience Research at the University of California, Irvine.