Biochemical Differences Between the Response to High Intensity versus Moderate Exercise

In this study, we asked the question whether the cellular senescence-lowering effect of exercise in human skeletal muscle can occur only at the intensity sufficient to induce DNA damage and inflammation. Biopsied vastus lateralis of 9 sedentary men (age 26.1 ± 2.5 y) were assessed before and after a single bout of moderate steady state exercise (SSE, 60% maximal aerobic power) and high intensity interval exercise (HIIE, 120% maximal aerobic power). Increases in cell infiltration (+1.2 folds), DNA strand break (+1.3 folds), and γ-H2AX+ myofibers (+1.1 folds) occurred immediately after HIIE and returned to baseline in 24 hours. Muscle p16Ink4a mRNA decreased 24 hours after HIIE. SSE had no effect on cell infiltration, p16Ink4a mRNA, and DNA strand break in muscle tissues. The major findings are as follows: (1) Cellular senescence-lowering effect of aerobic exercise can occur only at high intensity. SSE with similar exercise work failed to lower the p16INK4a mRNA in human skeletal muscle within the 24-h recovery period; (2) HIIE triggered immediate increases in cell infiltration and γ-H2AX+ myofibers, followed by a decreased p16INK4a mRNA in human skeletal muscle 24 hours after recovery; (3) By further examining the individual responses, the senolytic effect of HIIE were contributed solely from those participants with high pre-exercise p16INK4a mRNA in skeletal muscles. High intensity exercise is known to cause greater levels of lactate production and acidosis t...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs