運動對細胞老化的影響

The Impact of Exercise on Cellular Senescence

細胞受自由基、低氧、紫外光、幅射等的刺激，易造成細胞老化，與細胞凋亡有所不同，特徵包括端粒長度及端粒酶活性的減少、細胞形貌的平坦與擴張、阻抗細胞的凋亡、增加發炎、生長因子及β-半乳糖苷酶的活性等。細胞內DNA端粒是觀察細胞老化的關鍵。人體隨著年齡增加，端粒是呈現越短的情形，研究顯示端粒長度減少與部分疾病的發病率及死亡率具有關聯性，甚至有可能產生老年性腫瘤。單次高強度的運動不會對端粒產生影響，而長期運動能增加對端粒的保護。但在老年族群上有長期運動者，其端粒長度較能維持，年輕族群則無此差異。綜言之，不論任何年齡，參與適度規律運動都能增加端粒的保護因子，以及減少促細胞老化因子的表現。

When cells are stimulated by free radicals, hypoxia, ultraviolet (UV) light, or radiation, etc., it could easily lead to cell aging, which is different from apoptosis. The characteristics of cellular senescence, include reduced telomere length and telomerase activity, a flat morphology, increased resistance to apoptosis, as well as elevated levels of inflammation, growth factors and senescence-associated β-galactosidase. DNA telomeres play an important role in cellular senescence. Telomere length in humans is emerging as a biomarker of senescence because its shortening is associated with aging. Many researches also indicate that reduced telomere length is correlated to the incidence and mortality of some diseases, as well as age-related tumors. A single high-intensity exercise does not have any effect on telomere, but regular exercise, long-term, can increase the protection of the telomere. This is especially true in the elderly population than in younger individuals, which can benefit from long-term exercise that will help with the maintenance of telomere length. In summary, regular exercise can increase the positive effect of telomere-protecting factors and decrease the levels of senescence-associated factors.