Can Strength Training and Cardio Turn Back the Clock: The Cross-Organ "Rejuvenation Network" — How Exercise Slows Molecular Aging

1. What is the News?

The September 13, 2025 issue of WIRED Japan introduced a recent review suggesting that exercise can slow the progression of the "molecular clock," or epigenetic clock (biological age based on DNA methylation). The key point is that structured and repetitive exercise may be more effective than daily activities.WIRED.jp

2. What is the Epigenetic Clock?

The epigenetic age is an indicator that reflects the "wear and tear" of cells and tissues, rather than chronological age. It deciphers methylation patterns on DNA using machine learning to observe the difference from actual age (acceleration/deceleration). While it is rapidly becoming a standard in aging research, results can vary depending on which clock (PhenoAge/GrimAge, etc.) is used.BioMed Central

3. The "Effective Exercise" and "How it Works" as Indicated by the Review

A perspective by Takushi Kawamura and colleagues from Tohoku University cross-examined studies on animals and humans to organize the impact of exercise on epigenetic age. The conclusion is simple.

• Structured exercise (planned, repetitive, goal-oriented) has a stronger anti-aging effect than light daily activities.

• In particular, high cardiorespiratory fitness (VO₂max) is strongly associated with less age acceleration.dx.doi.org

There is also real data. An experiment involving 8 weeks of aerobic and strength training for middle-aged to elderly women reported that their epigenetic age rejuvenated by an average of 2 years. This molecular-level adaptation is difficult to achieve with just extended light walking.dx.doi.org

On the other hand, a correlation was also found that higher VO₂max in elderly men is associated with slower aging. The fact that endurance indicators were more strongly linked to molecular age than muscle strength is suggestive.dx.doi.org

4. It's Not Just Muscles That "Benefit"

Beyond skeletal muscles, the potential for slower aging has been demonstrated in animal models for the heart, liver, adipose tissue, and intestines. Comparative studies also show that Olympic athletes, who have used their bodies extensively and intensely, age slower at the molecular level than their peers. The concept of a "rejuvenation network" connecting organs supports the systemic effects of exercise.dx.doi.org

5. However, Caution is Needed with "Rejuvenation"

Let's pause here. Rejuvenated DNA methylation does not necessarily mean a longer lifespan, and aging is multifactorial. Recent large-scale clinical trials have reported that the combination of Omega-3, Vitamin D, and exercise can "delay biological age by several months," but the long-term impact on healthy lifespan and disease outcomes is still uncertain, according to experts. In short, improvement of the "clock" is a promising sign but not conclusive evidence.The Guardian

6. Implementation Tips—An Evidence-Based "Exercise Prescription"

• The base is moderate to high-intensity aerobic exercise (jogging, biking, intervals) plus resistance training about twice a week.

• Incorporate strategies to boost VO₂max (hill runs, tempo runs, HIIT, etc.) within a manageable range.

• Use 8 weeks as a milestone, optimizing sleep, nutrition, and stress management simultaneously, and record changes in blood and fitness indicators to visualize short-term responses.

• Those with medical histories should consult a doctor, and adjust intensity using **Rate of Perceived Exertion (RPE)** or heart rate.
  (The above are practical tips based on trends from the studies cited in this article and are not medical advice.)

7. Decoding Reactions on Social Media

The starting point of the spread was WIRED's post on X. It spread to health and sports accounts, with trainers and medical professionals sharing it in the context of emphasizing the importance of continuous exercise.X (formerly Twitter)

For example, a doctor from a clinic in Tokyo commented, "There are tests, but ultimately, sustained exercise is key," showing the alignment between clinical intuition and research reviews.X (formerly Twitter)

On the other hand, there was also caution about the word **"rejuvenation"** taking on a life of its own through news aggregators. The background includes the diversity of epigenetic clocks and the variability between indicators. While reviews in clinical epigenetics show a trend of slowing age acceleration with reduced sedentary time and increased activity, there is variability in effect size and reproducibility.Livedoor News

8. Conclusion—"Effective" Exercise is "Sustainable" Exercise

What this review teaches us is that even short-term interventions can shift molecular age indicators, and that long-term fitness building may slow the progression of aging. While recognizing the limitations of measurement methods and causality, the strategy of accumulating "moderate to high-intensity aerobic exercise plus strength training" safely and consistently is the best investment for yourself now and in the future.

References and Sources (Main)

• WIRED Japan "Sustained exercise slows aging at the molecular level: Research results" (2025/09/13).WIRED.jp

• Kawamura T. et al., "Exercise as a geroprotector: focusing on epigenetic aging" (Aging, 2025) and press release.dx.doi.org

• Review of epigenetic clocks × physical activity (Clinical Epigenetics, 2024).BioMed Central

• DO-HEALTH related reports (including cautious views on aging assessment using epigenetic clocks).The Guardian

• WIRED's X post and examples of doctor posts.X (formerly Twitter)