Resistance Training and Skin Aging: What One Trial Found

Search for exercise and skin and you will find a great deal of confident writing built on almost nothing. So it is worth being upfront about what exists here: one controlled trial that measured skin directly, one imaging study about posture, and a large empty space where most of the popular claims live.

The trial is worth reading, and the result most often quoted from it is weaker than the quoting suggests. The empty space is interesting too, because a lot of marketing is currently standing in it.

The trial

Aerobic exercise has been suggested as an anti-aging strategy for skin for a while. What nobody had done was compare it directly against lifting, which is what a group at Ritsumeikan University set out to fix in a study published in Scientific Reports in 2023.

They recruited 61 healthy sedentary middle-aged Japanese women and randomised them to sixteen weeks of either aerobic training or resistance training. Fifty-six completed the study and were analysed. Skin was assessed before and after, along with blood markers and gene expression in dermal fibroblasts, the cells that build the skin's structural matrix.

Both groups improved. Skin elasticity rose in both, and so did the structure of the upper dermis. On those measures, cardio and lifting looked equivalent.

Then there is dermal thickness, which is the number that gets quoted as the resistance-specific win, and it deserves a closer look than the abstract gives it. In the paper's own results table, dermal thickness went from 1.77 mm to 1.79 mm in the resistance group, p = 0.20, and did not move at all in the aerobic group, p = 0.93. Neither within-group change was statistically significant. The claim rests on a separate between-group comparison of the change scores, adjusted for baseline, and that comparison is marked in the figure as a trend at p < 0.10 rather than a significant difference.

The proposed mechanism has a similar structure. The researchers took blood plasma from participants before and after training and applied it to cultured human dermal fibroblasts, where plasma from the resistance group increased expression of biglycan, a proteoglycan involved in dermal structure. That is a reasonable line of inquiry, and it is not the same as showing more biglycan in the women's skin. The authors say so themselves, noting that their conclusion rests on three separate results and that more direct studies are needed to confirm the mechanism.

Three more things belong in your reading of it. Three of the authors are employees of POLA Chemical Industries, a cosmetics company. There was no inactive control group, only two exercise arms, so the improvements both groups shared cannot be cleanly separated from the passage of time or from taking part in a study. And this is 56 middle-aged Japanese women over sixteen weeks, which is a first result rather than a settled one.

What it measured, and what it did not

The trial measured skin structure: elasticity, the condition of the upper dermis, dermal thickness, and specific matrix components. Those are real, physical properties of skin, measured with instruments rather than opinions.

It did not measure wrinkles. It did not count lines, grade facial appearance, or ask anyone whether they looked younger. Thicker dermis with more biglycan is a plausible ingredient of skin that ages better, and it is not the same claim as fewer wrinkles, and the study does not license the second one.

The part with no evidence at all

The claim you will meet most often in this area is not about dermal thickness at all. It is about neck wrinkles, usually attached to a posture programme or a supplement.

Searching the literature for horizontal neck lines turns up a substantial body of work, and everything I could find was about treatment: hyaluronic acid fillers, polydioxanone threads, lasers, fat grafting. I could not find a study establishing that posture causes neck wrinkles, or an exercise intervention that measured them as an outcome. That is the limit of one person's search rather than a formal systematic review, so read it as such.

It is still worth stating, because a piece like this one could easily imply the opposite by placing a skin trial next to a posture study and letting the reader join them up.

Where this leaves things

The defensible version is short. Sixteen weeks of either kind of training improved measured skin elasticity and upper dermal structure in one uncontrolled-for-time trial. The resistance-specific dermal thickening that gets quoted from it is a trend, not a finding. Neck wrinkles, as far as exercise goes, are unstudied.

None of which is a reason to lift. The reasons to lift are the ones with a mountain of evidence behind them: strength, bone density, metabolic health, and in the context of the rest of this series, a neck that copes with a working day. If sixteen weeks of it also thickens your dermis slightly, that is a pleasant thing to find in the footnotes rather than a headline to train for.

References

1. Nishikori S, Yasuda J, Murata K, Takegaki J, Harada Y, Shirai Y, Fujita S. Resistance training rejuvenates aging skin by reducing circulating inflammatory factors and enhancing dermal extracellular matrices. Scientific Reports. 2023;13(1):10214. doi:10.1038/s41598-023-37207-9. Free full text. Note: three authors are employees of POLA Chemical Industries.