What if staying young wasn’t just about how much you move, but how you actually move your body? A new study reveals that our muscles can produce a powerful anti-aging molecule. The molecule, called CLCF1, is released mainly during resistance training and seems to help preserve muscle strength, bone density, and overall resilience as we age.

The findings could reshape how we think about exercise, aging, and even future drug therapies designed to mimic the benefits of physical activity. For years, scientists have known that exercise helps us stay healthier longer, but they could never figure out why the same workout that works wonders for young adults seems less effective in older people.

The new study offers a clue, and it all comes down to how our muscles talk to the rest of the body using tiny signaling molecules called myokines. CLCF1 is one of them. It turns out, while young muscles release plenty of CLCF1 during aerobic or strength workouts, older muscles don’t, unless they’re properly stimulated.

“This research provides a biological basis for why exercise becomes less effective with age, and it lays the groundwork for developing new therapeutic strategies for healthy aging,” Yong Ryoul Yang, one of the study authors and an expert on aging at the Korea Research Institute of Bioscience & BioTechnology, said.

Role of CLCF1 in healthy aging

Cardiotrophin-like cytokine factor 1 (CLCF1) is produced by skeletal muscle during exercise and plays a role in supporting muscle and bone health. During their study, the researchers noticed that in young adults, both resistance training and high-intensity interval training (HIIT) caused a rise in circulating CLCF1 immediately after exercise.

They further discovered that people who were more physically active also had higher resting levels of the molecule. However, in older adults, the pattern was very different. Simply walking on a treadmill for an hour, a typical form of cardio, didn’t lead to any real increase in CLCF1 levels, not even after weeks of regular workouts.

Instead, what worked for them was a 12-week strength training program done three times a week. Older participants who followed this routine showed a significant boost in CLCF1 levels. Their muscles and bones began showing signs of rejuvenation, similar to younger individuals. The researchers believe this delayed but clear response highlights how essential resistance training becomes as we age.

“We demonstrate that both resistance training for 16 weeks and resistance band exercise for 12 weeks significantly elevated plasma CLCF1 levels in older adults,” the study authors said.

Moreover, to understand why older muscles weren’t responding well to cardio, the team dug deeper. They studied mice and found the same trend. Older mice didn’t produce much CLCF1 after aerobic exercise. 

However, when scientists gave the mice recombinant CLCF1, a lab-made version of the molecule, their muscle strength and bone density improved, even without exercise. The problem didn’t seem to be the gene for CLCF1 itself (which was still present), but a partner protein called CRLF1.

“Our analysis demonstrated that CLCF1 expression remained stable with age, whereas cytokine receptor-like factor 1 (CRLF1), a protein crucial for CLCF1 secretion, exhibited a significant decline in expression,” the study authors note.

This protein helps transport and release CLCF1, and its levels drop as we age. Without enough CRLF1, older muscle cells can’t release CLCF1 efficiently during cardio workouts. Further experiments showed that when CLCF1 was blocked, the health benefits disappeared, proving that this molecule plays a direct role in protecting aging muscles and bones.

Resistance training is a must for healthy aging

This study offers strong biological proof that resistance training isn’t just about building muscle; it may actually rewind the clock on some aspects of aging. For healthy aging, it is crucial, and possibly even more important than cardio, as we grow older.

The researchers suggest that even simple bodyweight exercises or resistance bands, done consistently, can trigger the release of beneficial molecules like CLCF1. Plus, the earlier you start, the more muscle and bone savings you’ll have for the years ahead.

Overall, the discovery of CLCF1’s role in musculoskeletal health opens up exciting new possibilities. For instance, CLCF1 could also become part of a treatment for age-related conditions like sarcopenia (muscle loss) or osteoporosis. Hopefully, further research will reveal new ways in which scientists could harness the potential of CLCF1.

“These findings collectively suggest that CLCF1 may contribute to the regulation of age-associated musculoskeletal deterioration, and warrant further investigation into its potential role as a modulator of musculoskeletal health during aging,” the study authors said.

The study is published in the journal Nature Communications.