Normative data for the 10-min lean test in adults without orthostatic intolerance.

Background: Orthostatic intolerance syndromes such as Orthostatic Hypotension (OH) and Postural Orthostatic Tachycardia Syndrome (PoTS) are common symptoms seen in post-infection conditions and other neurological conditions with autonomic dysfunction. The 10-min Lean Test (LT) is an objective clinical test used to assess these symptoms and direct management. There is, however, no robust literature on normative data for this test, particularly from a younger population. Aims: The aim of this study was to produce a healthy control data set for LT, which can be used for comparison with the patient population with health conditions. Methods: Individuals recruited into the study had no history or symptoms of orthostatic intolerance; autonomic dysfunction; post-infection conditions (such as long COVID); or other neurological conditions with hemodynamic instability. Participants were primarily recruited from the general population in a metropolitan city. All participants underwent a standardized LT. Lying Blood Pressure (BP) and Heart Rate (HR) after 2 min of lying down supine was recorded, followed by BP and HR recordings at every minute of standing (leaning against a wall) up to 10 min, along with recording subject-reported symptoms at each time point. Results: A complete dataset was available for 112 individuals (60.7% Female, 39.3% Male). The population was 61.6% Caucasian, 8.0% Asian, 3.6% Black/Caribbean, 9.8% Mixed, and 17.0% Other; the mean age was 35.3 ± 15.1, with a BMI of 24.8 ± 4.0; 30.6% of individuals had a background medical condition, but none of the exclusion criteria. During LT, upon standing, the average change of HR was an increase of 9.89 ± 8.15 bpm. The sustained HR increase (HR increase sustained at two consecutive readings) was an average of 6.23 ± 6.94 bpm. The predominant response with BP was an increase of systolic BP, with the average initial increase being 7.55 ± 10.88 mmHg. None of the participants met the diagnostic criteria for symptomatic OH or PoTS during LT. Conclusion: For the first time in the current literature, 10-min LT data from a relatively younger population without orthostatic intolerance have been gathered. This normative data will help interpret LT findings in younger patients with orthostatic Intolerance better and be useful in managing dysautonomia in specific conditions.