Many people slather on serums and lotions in the hope of achieving fresher, younger skin. But for surprisingly effective results, try lifting weights.
A new study published in Scientific Reports found that both aerobic exercise and weight training altered gene expression and improved the underlying health of facial skin cells and tissue. However, resistance workouts produced benefits beyond those of the endurance exercise.
The findings "add to the evidence supporting that exercise" of any kind "is beneficial to skin health," said Mark Tarnopolsky, a professor, physician and director of the Neuromuscular and Neurometabolic Clinic at McMaster University in Hamilton, Canada. He has studied exercise and skin but was not involved with the new research.
People's skin grew "more youthful at a cellular level" after they began exercising, said Satoshi Fujita, an exercise scientist at Ritsumeikan University in Kyoto, Japan, who oversaw the new study. The most pronounced effects occurred when people lifted weights.
The study involved middle-aged Japanese women but has potential relevance for any of us with skin and a normal measure of vanity, or at least a healthy regard for our skin's well-being, especially if we aren't weight training.
Endurance exercise can help your skin
Skin is not an obvious beneficiary of exercise. We can see or feel how physical activity reshapes our muscles, heart, lungs and other organs. It's also quite beneficial for our liver. But our skin? Some people might even expect the reverse - that exercise, especially bouncy activities such as running, would stretch and harm skin's structure and appearance.
But Fujita suspected otherwise, even though little past research had examined exercise and skin. He was aware of one 2015 study, led by Tarnopolsky, during which a large group of people, some of them active and others sedentary, bared buttocks for a skin biopsy.
In Tarnopolsky's study, active people's skin displayed a thinner stratum corneum, the outer layer of skin, and thicker dermis, a deeper, structural layer compared to the skin of inactive people of the same age. Their skin cells also harbored more and healthier mitochondria, the energy centers of cells. These differences are all associated with younger skin.
In addition, when he and his colleagues had sedentary older men and women start jogging or cycling a few times a week for three months, the outer layer of their buttocks skin desirably thinned and inner layer grew, while their skin cells added mitochondria.
In effect, their skin gained youthfulness.
What weight training adds to your skin-care routine
But that study focused exclusively on endurance exercise. Fujita, who lifts weights in addition to frequent aerobic training, wondered whether resistance workouts might have similar or perhaps superior impacts on the inner health of skin.
So he and his colleagues gathered 56 sedentary, middle-aged women and assessed the elasticity, thickness and structure of the dermal layers in their facial skin, using ultrasound and other measures. They also drew blood, checking it for a variety of substances and adding drops of it to isolated facial skin cells in Petri dishes.
Then they assigned half of the women to start cycling for 30 minutes, twice a week. The rest began lifting weights, also for about 30 minutes, twice a week.
After 16 weeks, the researchers repeated all of the tests.
The women generally were fitter if they had cycled and stronger if they had lifted, indicating the exercise had changed them.
Their facial skin differed now, too. It had improved elasticity, meaning it was slightly less saggy and snapped back into shape better when stretched. Its extracellular matrix, or the biological scaffolding that provides structure to skin tissue, was also denser, while genes involved in the creation of skin collagen were busier.
These are all hallmarks of skin rejuvenation and occurred however the women exercised.
But only resistance training bumped up the thickness of the dermal layer, apparently by increasing the activity of several specialized genes that pump out proteins designed to build and strengthen connective tissue.
Fujita isn't certain why endurance exercise didn't bulk up the women's dermal layer in his group's study.
The scientists also didn't assess the appearance of the women's skin, although "theoretically, these changes may reduce wrinkles, improve appearance and help people look younger," Fujita said.
Overall, the findings "suggest that the skin is strongly influenced not only by external factors such as UV radiation and dryness," he continued, "but also by internal factors" such as gene expression and inflammation, that can change when you exercise.
A new reason to start lifting weights
They would also seem to be telling us that it's time to start lifting weights, if we're not. "It is possible to expect an additive effect of skin improvement when both resistance and aerobic exercise are combined," he said.
The study's limitations are many, however. It was small, short-term and included no one who wasn't middle-aged, Japanese, sedentary and female. It also had no control group.
The findings "seem reasonable." But "I don't think they mean anything definitive," said David Sawcer, a clinical associate professor of dermatology at the Keck School of Medicine at the University of Southern California in Los Angeles.
More and larger experiments are needed, as per usual in science.
Even in advance of more research, though, Fujita hopes his study "will encourage many people to acquire exercise habits," he said - with the caveat that we protect our skin with sunscreen and proper clothing if we work out outside.
"I am a 53-year-old male," he continued, "and I regularly perform strength and aerobic training in the morning, and I am often told that my skin looks very smooth for my age."
