2026-10-07T02:22:55Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33972538 2026-09-23T10:18:19Z category_31226 category_31460 category_33959 portal_2 item_type_3 month_year_09_2026

Supplementary information files for "At least 10 minutes of seated rest is required for stabilisation of blood-based hydration biomarkers" Kirsty Reynolds (14962183) Samantha Rowland (4742598) Mark Funnell (1253949) Tom Clifford (7468394) Liam Heaney (5153435) Stephen Mears (1258791) Stephen Bailey (2940720) Lewis James (1249500) Clinical sciences Medical physiology Sports science and exercise Sports Sciences Circulation Phlebology Urinalysis Plasma Diagostics Fitness Physiology Thermal regulation and hydration in exercise physiology Supplementary files for article "At least 10 minutes of seated rest is required for stabilisation of blood-based hydration biomarkers" Postural changes elicit well-described haemodynamic effects on plasma volume, affecting blood-based hydration variables. While the time required for plasma volume stabilisation is well-established for supine rest, less is known for blood samples collected in a seated position, as is commonplace in physiology and nutrition experiments. Seventeen healthy participants (9 males; 8 females) stood stationary for 20 min in an upright position before walking on a treadmill at 4 km/h for 20 min (to simulate active travel to blood sampling locations). After walking, participants sat upright (within 7 ± 1 s), and venous blood samples were drawn from a cannula at 0, 5, 10, 20, 30 and 40 min after sitting. Time points were compared to 40 min. At 0 and 5 min, blood (0 min: -3.3%; P < 0.001; 5 min: -1.2%; P = 0.034) and plasma (0 min: -5.9%; P < 0.001; 5 min: -1.7%; P = 0.035) volume were lower than 40 min values. Conversely, plasma osmolality was higher at 0 min (+ 0.61%; P = 0.005) and 5 min (+ 0.55%; P = 0.007), whilst blood/plasma volume and plasma osmolality were not different from 10 min onwards. Plasma sodium, potassium and chloride concentrations were not different from 40 min throughout the sitting period ( P ≥ 0.056). These data demonstrate that blood/plasma volume, as well as plasma osmolality were affected by posture and/or walking, but all are not significantly different from 40 min within 10 min of seated rest. Therefore, studies involving blood-based hydration measures taken in an upright seated position should allow at least 10 min of postural control prior to sampling. © The Author(s), CC BY 4.0 2026-09-23T00:00:00Z Dataset Dataset 10.17028/rd.lboro.33972538.v1 https://figshare.com/articles/dataset/Supplementary_information_files_for_At_least_10_minutes_of_seated_rest_is_required_for_stabilisation_of_blood-based_hydration_biomarkers_/33972538 CC BY 4.0