Fig. 2.

Effects of aging and exercise of different durations on cardiac rhythm of Drosophila. a Representative M-mode traces (20 s) from high-speed movies for semi-intact flies that are 2 and 6 weeks old, illustrating qualitative differences in heart function parameters: heart period (HP, horizontal blue line), diastolic interval (DI, horizontal green line), diastolic diameter (vertical green line), systolic interval (SI, horizontal red line), and systolic diameter (vertical red line). b Heart rate. c Heart period. d Diastolic interval. e Systolic interval. f Arrhythmicity index, defined as standard deviation of the heart period. g Automated analysis of fibrillation obtained from M-mode traces. *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