## 2 Materials and Methods
Based on the currently stated purpose and prior research assessing microvascular reperfusion in women during various stages of the menstrual cycle as well as with/without the use of an oral contraceptive ([PERSON] et al., 2018), it was our interpretation that the likely variation in the menstrual cycle did not substantially affect the present results. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Participant Characteristics** & **Men (n = 15)** & **Women (n = 14)** & **Lower-Upper Cl955; \(p\)** \\ \hline Age (yrs) & \(21\pm 3\) & \(21\pm 2\) & \(-2.3\) to \(1.8\); \(0.08\) \\ Height (cm) & \(174.7\pm 10.2\) & \(164.2\pm 11.2\) & \(-18.7\) to \(-2.4\); \(0.01\) \\ Weight (kg) & \(83.7\pm 12.0\) & \(65.0\pm 9.4\) & \(-27.0\) to \(-10.5\); \(<0.001\) \\ Step Count & \(9031.7\pm 3433.1\) & \(7582.0\pm 2748.9\) & \(-2880.0\) to \(1227.1\); \(0.42\) \\ Body Composition & & & \\ Body Mass Index (kg/m\({}^{2}\)) & \(27.4\pm 2.6\) & \(24.5\pm 23.7\) & \(-5.3\) to \(-0.5\); \(0.02\) \\ Body Fat (\%) & \(17.8\pm 3.5\) & \(24.6\pm 6.2\) & \(3.0\) to \(10.6\); \(0.001\) \\ Fat Mass (kg) & \(14.8\pm 3.8\) & \(15.9\pm 6.1\) & \(-2.8\) to \(4.9\); \(0.584\) \\ Learn Mass (kg) & \(68.7\pm 10.5\) & \(48.8\pm 5.2\) & \(-26.4\) to \(-13.3\); \(<0.001\) \\ Ultrasound Measures & & & \\ Brachial Artery Diameter (cm) & \(0.36\pm 0.05\) & \(0.29\pm 0.05\) & \(0.03\) to \(0.1\); \(0.002\) \\ Brachial Artery Velocity (cm/s) & \(30.9\pm 14.3\) & \(24.2\pm 11.1\) & \(-6.7\) to \(4.8\); \(0.17\) \\ Forearm Adipose Tissue (cm) & \(0.30\pm 0.06\) & \(0.22\pm 0.1\) & \(-0.09\) to \(-0.04\); \(0.02\) \\ \hline \hline \end{tabular}  
* Independent \(t\)-tests, bolded \(p\)-values correspond to significant at the \(\leq\)0.05 level. Cl95% = 95% confidence interval of mean differences (men–women).  
\end{table} 
Table 1: Participant characteristics. Figure 1: Experimental design. Figure 1 depicts the raw data (n = 1) for the NIRS-derived variable, O2 Hb during resting venous occlusion intervals, the 5 min arterial occlusion, and the reactive hyperemic venous occlusion intervals. An example of a participant’s forearm is depicted with the strain-gauge located on the forearm, and the NIRS device just below the strain-gauge. The boxed tracings depict reactive hyperemia captured by venous occlusions intervals with progressively declining rates of increase. VOP = venous occlusion plethysmography, NIRS = near-infrared spectroscopy, O2 Hb = oxygenated hemoglobin. Power Analysis. Based on a previous study [3], an a priori power analysis was conducted using a moderate effect size. G*Power (v. 3.1.9.7) was used to evaluate a bivariate normal correlation model with the following inputs: (1-\(\beta\) = 0.80, \(\eta^{2}\) = 0.59, \(\alpha\) = 0.05). This recommended a total sample size of 17, but to ensure adequate power as well as to meaningfully assess potential sex differences, a total of 33 participants were recruited for the current investigation. Therefore, the current sample size, even with the removal of four participants, was likely sufficient for the testing of the stated hypotheses. Body Composition. Prior to experimental testing, the participants underwent body composition analysis to determine percent body fat, fat mass, and lean mass via a FIT3D scan based on the guidelines of the manufacturer (FIT3D156 ProScanner, Redwood City, CA, USA). The 3D optical scanning has been shown to produce similar results compared to the accepted gold-standard four-compartment model [35]. A single researcher was responsible for collecting and inputting height, age, and sex into the Fit3D software (version 2.1.0), and the participants were instructed to all remove clothing, except undergarments. Further instructions were to stand tall, to center their feet on the markers on the turntable, and to grasp the hand grips with arms abducted at 45\({}^{\circ}\). Ultrasonography. Once in a rested state, brachial artery diameter and blood flow velocity were assessed with a digital ultrasound machine (Logiq E R7-ext Gen, GE Healthcare, Chicago, IL, USA).