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Record W2999862108 · doi:10.1113/jp278827

Evidence for temperature‐mediated regional increases in cerebral blood flow during exercise

2020· article· en· W2999862108 on OpenAlexafffund
Hannah G. Caldwell, Geoff B. Coombs, Connor A. Howe, Ryan L. Hoiland, Alexander Patrician, Samuel J. E. Lucas, Philip N. Ainslie

Bibliographic record

VenueThe Journal of Physiology · 2020
Typearticle
Languageen
FieldMedicine
TopicThermoregulation and physiological responses
Canadian institutionsOkanagan University CollegeUniversity of British Columbia, Okanagan CampusUniversity of British Columbia
FundersCanada Research Chairs
KeywordsCerebral blood flowMedicineBlood flowInternal medicineCardiologyBlood pressureHemodynamicsMiddle cerebral arteryAnesthesiaIschemia

Abstract

fetched live from OpenAlex

Key points Aerobic exercise elicits increases in cerebral blood flow (CBF), as well as core body temperature; however, the isolated influence of temperature on CBF regulation during exercise has not been investigated The present study assessed CBF regulation and neurovascular coupling during submaximal cycling exercise and temperature‐matched passive heat stress during isocapnia (i.e. end‐tidal was held constant) Submaximal cycling exercise and temperature‐matched passive heat stress provoked ∼16% increases in vertebral artery blood flow, independent of changes in end‐tidal and blood pressure External carotid artery blood flow increased by ∼43% during both exercise and passive heat stress, with no change in internal carotid artery blood flow Neurovascular coupling (i.e. the relationship between local increases in cerebral metabolism and appropriately matched increases in regional cerebral blood flow) is preserved during both exercise and temperature‐matched passive heat stress Abstract Acute moderate‐intensity exercise increases core temperature ( T c ; +0.7‐0.8°C); however, such exercise increases cerebral blood flow (CBF; +10‐20%) mediated via small elevations in arterial and metabolism. The present study aimed to isolate the role of T c from on CBF regulation during submaximal exercise. Healthy adults ( n = 11; 10 males/one female; 26 ± 4 years) participated in two interventions each separated by ≥48 h: (i) 60 min of semi‐recumbent cycling (EX; 50% workload max) and (ii) 75 min of passive heat stress (HS; 49°C water‐perfused suit) to match the exercise‐induced increases in T c (EX: Δ0.75 ± 0.33°C vs . HS: Δ0.77 ± 0.33°C, P = 0.855). Blood flow ( Q ) in the internal and external carotid arteries (ICA and ECA, respectively) and vertebral artery (VA) (Duplex ultrasound) was measured. End‐tidal and were effectively clamped to resting values within each condition. The Q ICA was unchanged with EX and HS interventions ( P = 0.665), consistent with the unchanged end‐tidal ( P = 0.327); whereas, Q VA was higher throughout both EX and HS (EX: Δ16 ± 21% vs . HS: Δ16 ± 23%, time effect: P = 0.006) with no between condition differences ( P = 0.785). These increases in Q VA contributed to higher global CBF throughout both EX and HS (EX: Δ12 ± 20% vs . HS: Δ14 ± 14%, time effect: P = 0.029; condition effect: P = 0.869). The Q ECA increased throughout both EX and HS (EX: Δ42 ± 58% vs . HS: Δ53 ± 28%, time effect: P < 0.001; condition effect: P = 0.628). Including blood pressure as a covariate did not alter these CBF findings (all P > 0.05). Overall, these data provide new evidence for temperature‐mediated elevations in posterior CBF during exercise that are independent of changes in and blood pressure.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.001
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.966
Threshold uncertainty score0.219

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.073
GPT teacher head0.312
Teacher spread0.240 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations23
Published2020
Admission routes2
Has abstractyes

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