Impact of COVID-19 on Ambulatory Daytime and Nighttime Blood Pressure in Young Otherwise Healthy Adults

BACKGROUND: COVID-19 has been shown to cause impairments in vascular function and elevations in resting sympathetic nerve activity in young otherwise healthy adults. Notably, our laboratory recently reported that persistence of COVID-19 symptoms beyond the acute phase of the illness (i.e., beyond 4 weeks) was accompanied by macro- and micro- vascular dysfunction as measured by flow mediated dilation and reactive hyperemia, respectively. Interestingly, despite consistent reports of vascular alterations, no studies have reported changes in resting blood pressure (BP) following COVID-19. One caveat is that BP has only been measured in the laboratory setting. Indeed, to date, no studies have assessed the effect of COVID-19 on ambulatory BP, which allows for a complete assessment of daytime and nighttime BP without the potential for well known "white coat" effects on BP. Thus, we aimed to investigate the effect of COVID-19 on 24-hr ambulatory BP in young adults diagnosed with COVID-19 within the preceding 6 months. We hypothesized that ambulatory BP would be greater in individuals who had COVID-19 compared to controls who never had COVID-19, and that those with symptoms would have higher BP compared to those who were asymptomatic at the time of testing. METHODS: We studied 21 young healthy adults who had a positive laboratory diagnosis of COVID-19 (COVID: 23 ± 1 years [Mean ± SE]; 12 ± 1 [range: 4 to 22] weeks since diagnosis; 13 females) and 10 controls (23 ± 1 years, 6 females) who never had COVID-19. Eleven individuals who had COVID-19 were asymptomatic at the time of testing while 10 were symptomatic. Ambulatory BP was measured using the Oscar 2 oscillometric monitor (Sun Tech Medical). Participants were instructed to perform normal daily activities but not to perform any exercise during the 24-hr period. Measurements were obtained every 20 min during daytime and every 30 min during nighttime. Average daytime, nighttime and 24-hr systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) were calculated. RESULTS: Daytime, nighttime, and 24-hr BPs were not different between control and COVID subjects (P > 0.05 for all comparisons). Similarly, there were no differences in any of the BP assessments between control, asymptomatic or symptomatic COVID subjects (e.g., daytime SBP: control 122 ± 4; asymptomatic 119 ± 4; symptomatic 125 ± 2 mmHg, P = 0.451). Interestingly, in the COVID group, daytime, nighttime, and 24-hr SBP, DBP, and MAP were inversely correlated with time since diagnosis (P < 0.05 for all with medium to large effect size). Multiple linear regression showed that after accounting for age, BMI, and physical activity (reported average exercise minutes/week), time since diagnosis was a significant predictor of daytime and 24-hr SBP, DBP, and MAP (e.g., daytime SBP: P = 0.028, β coefficient = -0.697). For nighttime BP, time since diagnosis was a significant predictor only for SBP. CONCLUSION: These preliminary data suggest that the effect of COVID-19 on ambulatory BP in young adults may be dependent on the time since diagnosis with higher daytime and nighttime BP present closer to the onset of the infection, which appeared to be independent of symptomology. Longitudinal follow up studies are warranted. © FASEB.