biostudies-literatureUnknown18(1)Burton C<h4>Background</h4>People with Long Covid (Post Covid-19 Condition) describe multiple symptoms which vary between and within individuals over relatively short time intervals. We aimed to describe the real-time associations between different symptoms and between symptoms and physical activity at the individual patient level.<h4>Methods and findings</h4>Intensive longitudinal study of 82 adults with self-reported Long Covid (median duration 12-18 months). Data collection involved a smartphone app with 5 daily entries over 14 days and continuous wearing of a wrist accelerometer. Data items included 7 symptoms (Visual Analog Scales) and perceived demands in the preceding period (Likert scales). Activity was measured using mean acceleration in the 3-hour periods preceding and following app dataPloS onee0280343https://www.ebi.ac.uk/biostudies/studies/S-EPMC9851560biostudies-literatureWithin and between-day variation and associations of symptoms in Long Covid: Intensive longitudinal study.PMC9851560Burton CGoodwill SThelwell MDalton CDawes HfalseWithin and between-day variation and associations of symptoms in Long Covid: Intensive longitudinal study.<h4>Background</h4>People with Long Covid (Post Covid-19 Condition) describe multiple symptoms which vary between and within individuals over relatively short time intervals. We aimed to describe the real-time associations between different symptoms and between symptoms and physical activity at the individual patient level.<h4>Methods and findings</h4>Intensive longitudinal study of 82 adults with self-reported Long Covid (median duration 12-18 months). Data collection involved a smartphone app with 5 daily entries over 14 days and continuous wearing of a wrist accelerometer. Data items included 7 symptoms (Visual Analog Scales) and perceived demands in the preceding period (Likert scales). Activity was measured using mean acceleration in the 3-hour periods preceding and following app data2023-01-01T00:00:00Z20232025-04-18T15:21:13.093Z2025-04-07T01:59:16.199ZS-EPMC98515603665683010.1371/journal.pone.0280343