Fig. 5
Ring unit analysis. Numbers of 50-μm-length ring units in the networks in different outer diameter ranges. Pooled data for 10 animals, with a total of 29,390 ring units included. a Control and exercised males; b control and exercised females; c control males and females; d exercised males and females. Ring frequency spectra of trained animals were significantly different from the sedentary ones in both males and females (** p < 0.01 with the χ2 probe). Note doubling of the 400-μm vessel units and substantial elevation of 200-μm vessel units in males in response to strenuous training. In females, the number of 150-μm vessel units was elevated, while there was a reduction in the 350-μm range. The ring frequency spectra of male animals were significantly different from the female ones in both the sedentary and exercised groups (p < 0.001 with the χ2 probe). In the control groups, the numbers of the larger (300–600 μm) vessels are larger, and the numbers of the smaller (200–250 μm) ring units are smaller in the male rats than in the female rats. In the exercised groups, there are more 350- to 600-μm vessels and fewer 200- to 250-μm vessels in male animals than in female animals. (a Chi-square = 646.858 with 12 degrees of freedom, p < 0.001. b Chi-square = 322.665 with 12 degrees of freedom, p < 0.001. c Chi-square = 613.675 with 12 degrees of freedom, p < 0.001. d Chi-square = 773.079 with 12 degrees of freedom, p < 0.001)