Infradian Rhythms in Cerebrovascular Oxygenation and Blood Volume in Humans at Rest: A 5-Year Study.
Adv Exp Med Biol
; 1438: 37-44, 2023.
Article
em En
| MEDLINE
| ID: mdl-37845437
ABSTRACT
BACKGROUND:
All parameters of human physiology show chronobiological variability. While circadian (cycle length ~ 24 h) rhythms of the neuronal, hemodynamic and metabolic aspects of human brain activity are increasingly being explored, infradian (cycle length > 24 h) rhythms are largely unexplored.AIM:
We investigated if cerebrovascular oxygen saturation (StO2) and blood volume ([tHb]) values measured over many years in many subjects during resting show infradian rhythmicity. SUBJECTS ANDMETHODS:
Absolute StO2 and [tHb] values (median over a 5 min resting-phase while sitting) were measured in 220 healthy subjects (age 24.7 ± 3.6 years, 87 males, 133 females) 2-4 times on different days over the right and left frontal lobe (FL) and occipital lobe (OL) by employing frequency-domain NIRS as part of different systemic physiology augmented functional near-infrared spectroscopy, SPA-fNIRS, studies. The data set consisted of 708 single measurements performed over a timespan of 5 years (2017-2021). General additive models (GAM) and cosinor modelling were used to analyze the data.RESULTS:
The GAM analysis revealed (i) a non-linear trend in the StO2 and [tHb] values over the 5-year span, (ii) a circannual (cycle length ~ 12 months) rhythm in StO2 at the FL (amplitude (A) 3.4%, acrophase (φ) June) and OL (A 1.5%, φ May) as well as in [tHb] at the OL (A 1.2 µM, bathyphase (θ) June), and (iii) a circasemiannual (cycle length ~ 6 months) rhythm in [tHb] at the FL (A 2.7 µM, φ March and September, respectively). Furthermore, the circannual oscillations of StO2 (at the FL) and [tHb] (at the OL) were statistically significantly correlated with the day length, outdoor temperature, humidity and air pressure. DISCUSSION ANDCONCLUSION:
We conclude that absolute values of StO2 and [tHb] show chronobiological variability on the group-level with a long-term nonlinear trend as well as circannual/circasemiannual rhythmicity. These rhythms need to be taken into account when defining reference values for StO2 and [tHb] and may correlate with the variability of cerebrovascular disease incidents over the year.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ritmo Infradiano
Limite:
Adult
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Female
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Humans
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Male
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article