Figure 1.

Ten-weeks swimming exercise induces physiological cardiac hypertrophy in rats. (A), The systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MBP) in the control (CON) and swimming exercise (EX) groups. (B), The heart rate (HR) in the EX group. (C, D), Ten-week swimming exercise increased the HW/BW and LV/BW ratios in the EX group. BW, body weight; LV, left ventricular weight; HW, heart weight. (E, F), Hematoxylin staining of LV myocytes in the CON group and EX group. Images were obtained at a magnification of ×400. (G–J), The levels of atrial natriuretic polypeptide (ANP) and the skeletal muscle α-actin (α-actin), and the ratio of α/β-myosin heavy chain (α/β-MHC) and levels of sarco-endoplasmic reticulum Ca²⁺-ATPase (SERCA-2α) in the CON group and EX group. (K), Diagram depicting the experimental process of this study. * P < 0.05, ** P < 0.01, EX group (n=16) vs. CON group (n=16). Data are presented as mean ± SD. Statistical significance was evaluated with the two-tailed Student's t test.