The largest organ in your body and a first line of defence against the external environment, the integumentary system protects the body from infection and injury. Its functions include Vitamin D synthesis, the production of melanin, thermoregulation, and more.
But as we age, the dermal and epidermal layers of our skin can become compromised in these functions and vulnerable to disease including infection and damage from sun radiation.
To help elucidate specific factors in skin aging, a 2015 study of humans and mice in Aging Cell, considered the characteristics of “reductions in cell proliferation, collagen synthesis, extracellular matrix remodelling, and altered epidermal morphology.” And while acknowledging the role of hormones and external influences on skin health, researchers proposed that the drivers of aging skin cells are “reduced energy metabolism, higher mitochondrial oxidative stress and pronounced mitochondrial DNA (mtDNA) deletions.” In short, the “mitochondrial free radical theory of aging.”
But what can we do about this?
In an interesting reveal, study authors suggest that mitochondrial metabolism in skin cells can be improved by endurance exercise. Specifically, they point to “exercise-induced IL-15 as a regulator of mitochondrial function” in the skin: “The expression of IL_15 in part through skeletal muscle AMP activated protein kinase (AMPK) is a central regular of this metabolism.“ Interleukin 15, a signalling molecule or cytokine, is known to play a role in the immune system of the skin.
The 2015 study found that 12 weeks of endurance exercise training in sedentary elderly adults increased collagen content, skin mtDNA copy number and serum concentration of IL-15.