Long COVID Does Not Impair Hemodynamic, Vascular, or Autonomic Responses to Maximal Exercise: Sex-Stratified Study in Young Adults

<b>Background/Objectives</b>: Long COVID (LC) has been linked to fatigue, exercise intolerance, and autonomic dysfunction, but sex-stratified data on cardiovascular responses to maximal exercise-an essential component of personalized medicine-are scarce. This study aimed to examine hemodynamic, autonomic, and functional responses during and up to 24 h after a cardiopulmonary exercise test (CPET) in young adults with and without Long COVID (LC). <b>Methods</b>: In this cross-sectional study, we assessed 38 physically active adults, who were allocated into four subgroups stratified by clinical condition (LC or control) and biological sex: control-female (CON-F; <i>n</i> = 10), LC-female (LC-F; <i>n</i> = 10), control-male (CON-M; <i>n</i> = 10), and LC-male (LC-M; <i>n</i> = 8). Outcomes included systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), cardiac output (CO), total (TPR) and peripheral vascular resistance (PVR), pulse wave velocity (PWV), augmentation index (AIx@75), and heart rate variability (HF, LF, LF/HF), assessed at rest, peak effort, recovery (1, 3, 5, 10, 30, and 60 min), and through 24 h ambulatory blood pressure monitoring (ABPM) after CPET. <b>Results</b>: SBP increase appropriately during exercise, with higher peaks in males (<i>p</i> < 0.01), and returned to baseline within 5 min across all groups. HR recovery was preserved; however, LC-F showed lower values than CON-F at 3, 5, and 10 min (126 vs. 144 bpm, <i>p</i> = 0.020; 119 vs. 136 bpm, <i>p</i> = 0.020; 94 vs. 109 bpm, <i>p</i> = 0.011), though all groups normalized by 60 min. PWV, AIx@75, TPR and PVR exhibited expected sex-related patterns without LC-related impairments. HRV indices showed transient post-exercise shifts (HF↓, LF↑, LF/HF↑). Ambulatory monitoring confirmed preserved circadian modulation, with normal systolic dipping (11-13%) and no abnormal nocturnal patterns. <b>Conclusions</b>: Young physically active adults with LC showed preserved hemodynamic, autonomic, and vascular responses during and after maximal exercise. These findings contribute to personalized medicine by showing that individualized, sex-stratified cardiovascular assessments reveal no clinically relevant impairments in this population, supporting tailored clinical decision making and exercise prescription.