Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome

BackgroundOrthostatic intolerance, with or without postural orthostatic tachycardia syndrome (POTS), is collectively referred to as orthostatic intolerance dysautonomia syndromes (OIDS). This condition often presents with daytime hyperventilation, which is considered to be secondary to sympathetic h...

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Main Authors: Amir Hashemizad, Jerriel Dela Cruz, Aditya Narayan, Andrew J. Maxwell
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-04-01
Series:Frontiers in Neurology
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Online Access:https://www.frontiersin.org/articles/10.3389/fneur.2025.1512671/full
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author Amir Hashemizad
Jerriel Dela Cruz
Aditya Narayan
Andrew J. Maxwell
author_facet Amir Hashemizad
Jerriel Dela Cruz
Aditya Narayan
Andrew J. Maxwell
author_sort Amir Hashemizad
collection DOAJ
description BackgroundOrthostatic intolerance, with or without postural orthostatic tachycardia syndrome (POTS), is collectively referred to as orthostatic intolerance dysautonomia syndromes (OIDS). This condition often presents with daytime hyperventilation, which is considered to be secondary to sympathetic hyperactivity. This hyperventilation appears to be a key characteristic in a newly described subset of patients with OIDS who also exhibit craniocervical instability, mast cell activation syndrome (MCAS), hypermobility spectrum disorder (HSD), and the phenomenon of alternating intracranial hypertension with hypotension due to cerebrospinal fluid (CSF) leaks, collectively termed Spiky-Leaky Syndrome (SLS).MethodsWe performed a retrospective review of clinical metabolic exercise data in young patients with SLS, comparing them to matched patients with OIDS and healthy controls (CTL). We assessed metabolic parameters at rest, at the anaerobic threshold (AT), and at maximal oxygen consumption (VO2max). The parameters included end-tidal CO2 (ETCO2), end-tidal O2 (ETO2), peak oxygen pulse, total work performed, and peak oxygen uptake efficiency slope (OUESp).ResultsOf 323 reviewed exercise stress tests, 44 were conducted on patients with SLS, 210 on those with OIDS, and 53 on healthy controls. VO2max, AT, peak oxygen pulse, total work performed, and OUESp were all significantly reduced in patients with OIDS and were further reduced in those with SLS. ETCO2 levels were notably lower at rest, at the time of the anaerobic threshold, and at the time of maximal oxygen uptake in the OIDS group, and even more so in the SLS group. These lower levels of ETCO2 persisted throughout exercise. In contrast, ETO2 demonstrated a similarly strong but opposite trend.ConclusionCompared to the control group, patients with OIDS—and especially those with SLS—exhibited reduced metabolic parameters, particularly a decrease in peak oxygen pulse and ETCO2 levels during both rest and exercise. These findings suggest a reduction in ventricular preload and chronic daytime hyperventilation. These exercise parameters may serve as markers for POTS physiology and sympathetic hyperactivity, both of which could play a role in the pathophysiology of SLS.
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spelling doaj-art-3a71831a43024cff8f5b72bbf2ec39c42025-08-20T02:27:46ZengFrontiers Media S.A.Frontiers in Neurology1664-22952025-04-011610.3389/fneur.2025.15126711512671Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky SyndromeAmir HashemizadJerriel Dela CruzAditya NarayanAndrew J. MaxwellBackgroundOrthostatic intolerance, with or without postural orthostatic tachycardia syndrome (POTS), is collectively referred to as orthostatic intolerance dysautonomia syndromes (OIDS). This condition often presents with daytime hyperventilation, which is considered to be secondary to sympathetic hyperactivity. This hyperventilation appears to be a key characteristic in a newly described subset of patients with OIDS who also exhibit craniocervical instability, mast cell activation syndrome (MCAS), hypermobility spectrum disorder (HSD), and the phenomenon of alternating intracranial hypertension with hypotension due to cerebrospinal fluid (CSF) leaks, collectively termed Spiky-Leaky Syndrome (SLS).MethodsWe performed a retrospective review of clinical metabolic exercise data in young patients with SLS, comparing them to matched patients with OIDS and healthy controls (CTL). We assessed metabolic parameters at rest, at the anaerobic threshold (AT), and at maximal oxygen consumption (VO2max). The parameters included end-tidal CO2 (ETCO2), end-tidal O2 (ETO2), peak oxygen pulse, total work performed, and peak oxygen uptake efficiency slope (OUESp).ResultsOf 323 reviewed exercise stress tests, 44 were conducted on patients with SLS, 210 on those with OIDS, and 53 on healthy controls. VO2max, AT, peak oxygen pulse, total work performed, and OUESp were all significantly reduced in patients with OIDS and were further reduced in those with SLS. ETCO2 levels were notably lower at rest, at the time of the anaerobic threshold, and at the time of maximal oxygen uptake in the OIDS group, and even more so in the SLS group. These lower levels of ETCO2 persisted throughout exercise. In contrast, ETO2 demonstrated a similarly strong but opposite trend.ConclusionCompared to the control group, patients with OIDS—and especially those with SLS—exhibited reduced metabolic parameters, particularly a decrease in peak oxygen pulse and ETCO2 levels during both rest and exercise. These findings suggest a reduction in ventricular preload and chronic daytime hyperventilation. These exercise parameters may serve as markers for POTS physiology and sympathetic hyperactivity, both of which could play a role in the pathophysiology of SLS.https://www.frontiersin.org/articles/10.3389/fneur.2025.1512671/fulldysautonomiaPOTSmast cell activation syndromeEhlers-Danlos syndromehypermobility spectrum disorderSpiky-Leaky Syndrome
spellingShingle Amir Hashemizad
Jerriel Dela Cruz
Aditya Narayan
Andrew J. Maxwell
Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome
Frontiers in Neurology
dysautonomia
POTS
mast cell activation syndrome
Ehlers-Danlos syndrome
hypermobility spectrum disorder
Spiky-Leaky Syndrome
title Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome
title_full Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome
title_fullStr Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome
title_full_unstemmed Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome
title_short Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome
title_sort hyperventilation during rest and exercise in orthostatic intolerance and spiky leaky syndrome
topic dysautonomia
POTS
mast cell activation syndrome
Ehlers-Danlos syndrome
hypermobility spectrum disorder
Spiky-Leaky Syndrome
url https://www.frontiersin.org/articles/10.3389/fneur.2025.1512671/full
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