Acute effects of a maximal cardiopulmonary exercise test on cardiac hemodynamic and cerebrovascular response and their relationship with cognitive performance in individuals with type II diabetes
Authors: Besnier F , Gagnon C , Monnet M , Dupuy O , Nigam A , Juneau M , Bherer L , Gayda M 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: Foundation. Main funding source(s): Mirella and Lino Saputo Research Chair in Cardiovascular Diseases and the Prevention of Cognitive Decline from Université de Montréal at the Montreal Heart Institute. Montreal Heart Institute and the EPIC Center Foundations. FB are financially supported by a grant from the Fonds de Recherche du Québec – Santé (FRQ-S).

Background/Introduction
Cardiovascular and cerebrovascular disease are prevalent in type 2 diabetes (T2D) patient. Among people older than 70 years with T2D, up to 45% of might have cognitive dysfunction. Cardiorespiratory fitness (V̇O2peak) correlate with cognitive performances in healthy subjects, older adults, and people with CV diseases. The relationship between cognitive functions, V̇O2peak, cardiac output and cerebral oxygenation/perfusion responses during exercise has not been studied in patients with T2D. Studying cardiac and cerebrovascular hemodynamic responses during cardiopulmonary maximal exercise test (CPET) and its recovery phase and their relationship with cognition could be useful to detect patients at greater risk of future cognitive dysfunction.

Purpose
1) To compare cerebral oxygenation/perfusion during a CPET and its post-exercise period (recovery), cognitive performances in T2D patients to those in healthy controls. 2) To examine if V̇O2peak, cardiac and cerebral hemodynamic are related to cognitive performances.

Methods
Nineteen T2D patients (61.9±7 years) and 22 healthy controls (HC) (61.8±10 years) were evaluated using a maximal CPET with impedance cardiography and cerebral oxygenation/perfusion (near-infrared spectroscopy) measure. The neuropsychological test battery evaluated short-term and working memory, processing speed, executive functions, and long-term verbal memory.

Results
T2D patients add a lower O2peak values compared to HC (34.5±5.6 vs 46.4±7.6 mL.kgFFM.min p&lt;0.001). Peak cardiac index are also lowered compared to HC (p&lt;0.05). Systemic vascular resistance index and systolic blood pressure at peak exercise were higher in T2D (p=0.005). Cerebral deoxyhemoglobin (HHb) during the 1st and 2nd min of the recovery remains significantly higher in HC compared to T2D (p&lt;0.05). Executive functions were significantly lower in T2D patients compared to HC (p=0.016). Processing speed, working and verbal memory were similar in both groups. Total haemoglobin (tHb) during exercise and recovery, and oxyhemoglobin (O2Hb) during recovery only negatively correlated with executive function (p&lt;0.05) in T2D patients (lower tHb values were associated with slower response times).

Conclusion
In addition to a reduced V̇O2peak and elevated vascular resistance, T2D patients showed a reduced cerebral O2Hb and HHb during early recovery (0 – 2 min) after peak exercise and a lower cognitive performance in executive function compared to healthy controls. Cerebrovascular responses with exercise and during the recovery phase could be a biological marker of cognitive impairment in T2D.