Effects of aging and exercise of different durations on the cardiac contraction of Drosophila. a–j Representative diastolic and systolic heart tubes from high-speed movies for semi-intact flies: diastolic diameter (vertical green line) and systolic diameter (vertical red line). a, b Diastolic and systolic heart tube for 2wC. c, d Diastolic and systolic heart tube for 6wC. e, f, g, h,i,j Diastolic and systolic heart tube for 6w_1.5hE, 6w_2.0hE, and 6w_2.5hE, respectively. k Systolic diameter. l Diastolic diameter. m Cardiac output, quantified as fractional shortening. *P < 0.05; **P < 0.01 using an independent-samples t test between 2wC and 6wC and using a one-way analysis of variance (ANOVA) followed by an LSD test among 6wC, 6w_1.5hE, 6w_2.0hE, and 6w_2.5hE. Sample size was 20 to 30 flies per group. Data are displayed as mean ± SEM