Table 2.

Summary Statistics of CPET Slope Variables

		Age
		8–10	11–13	14–15	16–18
ΔWR/ΔHR* (watt/beat/min)	Female	1.1 ± 0.2	1.4 ± 0.3	1.8 ± 0.4	1.8 ± 0.4
	Male	1.1 ± 0.2	1.5 ± 0.3	2.3 ± 0.6	2.4 ± 0.5
$\mathrm{\Delta }\stackrel{•}{\mathrm{V}}{\mathrm{O}}_2/\mathrm{\Delta }\mathrm{H}\mathrm{R}$* (mL/beat)	Female	9.6 ± 2.3	13.9 ± 3.9	17.8 ± 5.7	16.9 ± 3.5
	Male	11.3 ± 2.2	15.8 ± 4.5	23.0 ± 5.6	24.3 ± 6.9
$\mathrm{\Delta }\stackrel{•}{\mathrm{V}}{\mathrm{O}}_2/\mathrm{\Delta }\mathrm{W}\mathrm{R}$* (mL/min/watt)	Female	9.6 ± 1.2	10.1 ± 1.3	10.0 ± 1.2	9.9 ± 1.1
	Male	10.6 ± 1.7	10.9 ± 1.5	10.6 ± 1.4	10.5 ± 1.4
$\mathrm{\Delta }{\stackrel{•}{\mathrm{V}}}_{\mathrm{E}}/\mathrm{\Delta }\stackrel{•}{\mathrm{V}}\mathrm{C}{\mathrm{O}}_2$	Female	33.0 ± 4.5	31.7 ± 4.2	28.0 ± 4.4	27.8 ± 3.6
	Male	33.3 ± 5.2	29.5 ± 3.7	28.6 ± 4.3	26.8 ± 3.9

Values are mean ± SD.

^*Significantly different between boys and girls after controlling for age using ANCOVA.