Cerebral vasomotor reactivity during hypo- and hypercapnia in sedentary elderly and Masters athletes.
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ABSTRACT:
SUBMITTER: Zhu YS
PROVIDER: S-EPMC3734768 | biostudies-literature | 2013 Aug
REPOSITORIES: biostudies-literature
Publications
Cerebral vasomotor reactivity during hypo- and hypercapnia in sedentary elderly and Masters athletes.
Zhu Yong-Sheng YS Tarumi Takashi T Tseng Benjamin Y BY Palmer Dean M DM Levine Benjamin D BD Zhang Rong R
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 20130417 8
Physical activity may influence cerebrovascular function. The objective of this study was to determine the impact of life-long aerobic exercise training on cerebral vasomotor reactivity (CVMR) to changes in end-tidal CO2 (EtCO2) in older adults. Eleven sedentary young (SY, 27±5 years), 10 sedentary elderly (SE, 72±4 years), and 11 Masters athletes (MA, 72±6 years) underwent the measurements of cerebral blood flow velocity (CBFV), arterial blood pressure, and EtCO2 during hypocapnic hyperventilat ...[more]
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Project description:BackgroundAgeing is associated with decreased physical activity, obesity and subsequently an increased risk of developing type 2 diabetes mellitus (T2dm). Master athletes (MA) have initiated exercise or sport later in life or pursued a physically active lifestyle for an extended period. Subsequently, MAs have been proposed as a model of successful ageing as this active lifestyle is associated with health benefits including decreased health risk of chronic diseases and a reduction in premature mortality. Given long-term physical activity/exercise has previously been shown to be protective against hyperglycemia, a risk factor for T2dm, it is plausible that MA may have protective benefit against developing hyperglycemia. Therefore, the aim of this study was to investigate the prevalence of hyperglycemia via fasting plasma glucose (FPG) in MAs competing at the World Masters Games (WMG).MethodsThis cross-sectional, observational survey utilized an online survey using open-source web-based software was used to investigate MAs physiological and medical-related parameters. Over 28,000 MAs competed in the WMG, of which 8,072 MAs completed the survey. Of these MAs, a total of 486 (males 277, females 209; range 27 to 91 years, mean age 55.1 ± 10.2 years) attained recent pathology results which included FPG which was subsequently analyzed for this study. FPG and other outcome variables were compared between genders and to the Australian and United States general population.ResultsMean FPG for MAs was 5.03 mmol (±1.2, 95% CI [4.9-5.1] mmol) with majority (75.5%) of MAs reporting a normal (<5.5 mmol) FPG, followed by pre-diabetes (20.2%, >5.51 to <5.99 mmol) and abnormal (4.3%, >7.0 mmol). There was no significant difference (P = 0.333) in FPG between genders however, males had a slightly higher (+2.1%) FPG as compared to females (5.08 ± 1.2 mmol (95% CI [4.9-5.22] mmol) versus 4.98 ± 1.1 mmol (95% CI 4.8-5.1 mmol)). The majority of males (71.8%) and females (80.3%) were classified with a normal FPG. With regard to an abnormal FPG level, only 4.0% of males and 4.9% of females were classified abnormal which was suggestive of undiagnosed T2dm. With regard to age by decade, there was no significant difference (P = 0.06-1.00) between age groups and no relationship between the MAs' age and FPG (r = .054, P = 0.24). As a group, MAs had a significantly lower FPG as compared to the Australian (-3.2%, P = 0.005) and United States general populations (-13.9%, P < 0.001).ConclusionsMost, however not all, MAs were found to have normal glycaemia, with only a small percentage indicating a risk of developing T2dm (i.e., impaired fasting glucose) and a smaller percentage identified with an abnormal FPG, suggestive of T2dm. These findings suggest MAs appear to be at low metabolic risk for developing T2dm based upon FPG and the physical activity/exercise they complete as MAs may indeed be protective against hyperglycemia whilst maintaining an active lifestyle.
| S-EPMC9159136 | biostudies-literature
Project description:The purpose of this study was to test the hypothesis that changes in cerebral vasomotor reactivity (CVMR) after 1-yr aerobic exercise training (AET) are associated with cognitive performances in individuals with amnestic mild cognitive impairment (MCI). Seventy sedentary patients with amnestic MCI were randomized to 1-yr moderate-to-vigorous intensity AET or stretching and toning (SAT) interventions. Cerebral blood flow velocity (CBFV) with transcranial Doppler, mean arterial pressure (MAP) with finapres plethysmograph, and EtCO2 with capnography were measured during hyperventilation (hypocapnia) and a modified rebreathing protocol (hypercapnia) to assess CVMR. Cerebrovascular conductance index (CVCi) was calculated by CBFV/MAP, and CVMR by ΔCBFV/ΔEtCO2 and ΔCVCi/ΔEtCO2. Episodic memory and executive function were assessed using standard neuropsychological tests (CVLT-II and D-KEFS). Cardiorespiratory fitness was assessed by peak oxygen uptake (V̇o2peak). A total of 37 patients (19 in SAT and 18 in AET) completed 1-yr interventions and CVMR assessments. AET improved V̇o2peak, increased hypocapnic CVMR, but decreased hypercapnic CVMR. The effects of AET on cognitive performance were minimal when compared with SAT. Across both groups, there was a negative correlation between changes in hypocapnic and hypercapnic CVMRs in CBFV% and CVCi% (r = -0.741, r = -0.725, P < 0.001). Attenuated hypercapnic CVMR, but not increased hypocapnic CVMR, was associated with improved cognitive test scores in the AET group. In conclusion, 1-yr AET increased hypocapnic CVMR and attenuated hypercapnic CVMR which is associated cognitive performance in patients with amnestic MCI.NEW & NOTEWORTHY One-year moderate-to-vigorous intensity aerobic exercise training (AET) improved cardiorespiratory fitness (V̇o2peak), increased hypocapnic cerebral vasomotor reactivity (CVMR), whereas it decreased hypercapnic CVMR when compared with stretching and toning in patients with amnestic mild cognitive impairment (MCI). Furthermore, changes in hypercapnic CVMR with AET were correlated with improved memory and executive function. These findings indicate that AET has an impact on cerebrovascular function which may benefit cognitive performance in older adults who have high risk of Alzheimer's disease.
| S-EPMC8325610 | biostudies-literature
Project description:ObjectiveClassic methods for assessing cerebral autoregulation involve a transfer function analysis performed using the Fourier transform to quantify relationship between fluctuations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). This approach usually assumes the signals and the system to be stationary. Such an presumption is restrictive and may lead to unreliable results. The aim of this study is to present an alternative method that accounts for intrinsic non-stationarity of cerebral autoregulation and the signals used for its assessment.MethodsContinuous recording of CBFV, ABP, ECG, and end-tidal CO2 were performed in 50 young volunteers during normocapnia and hypercapnia. Hypercapnia served as a surrogate of the cerebral autoregulation impairment. Fluctuations in ABP, CBFV, and phase shift between them were tested for stationarity using sphericity based test. The Zhao-Atlas-Marks distribution was utilized to estimate the time-frequency coherence (TFCoh) and phase shift (TFPS) between ABP and CBFV in three frequency ranges: 0.02-0.07 Hz (VLF), 0.07-0.20 Hz (LF), and 0.20-0.35 Hz (HF). TFPS was estimated in regions locally validated by statistically justified value of TFCoh. The comparison of TFPS with spectral phase shift determined using transfer function approach was performed.ResultsThe hypothesis of stationarity for ABP and CBFV fluctuations and the phase shift was rejected. Reduced TFPS was associated with hypercapnia in the VLF and the LF but not in the HF. Spectral phase shift was also decreased during hypercapnia in the VLF and the LF but increased in the HF. Time-frequency method led to lower dispersion of phase estimates than the spectral method, mainly during normocapnia in the VLF and the LF.ConclusionThe time-frequency method performed no worse than the classic one and yet may offer benefits from lower dispersion of phase shift as well as a more in-depth insight into the dynamic nature of cerebral autoregulation.
| S-EPMC5531479 | biostudies-literature
Project description:Patent Foramen Ovale and impaired cerebral hemodynamics were proposed among the pathophysiological mechanisms explaining the increased risk for stroke in patients with Migraine with Aura (MA). Our study aimed at comparing the vasomotor reactivity (VMR) of the anterior and the posterior cerebral circulation in patients with Migraine with Aura, in patients with acute vascular ischemic accidents, and in controls. We hypothesized that VMR in MA patients is preserved in the anterior circulation and reduced in the posterior circulation. We prospectively assessed with Transcranial Doppler the vasomotor reactivity to breath holding of the Middle and Posterior Cerebral Arteries (MCA, PCA) in MA patients, in acute vascular patients and healthy controls. We also evaluated the possible effect of clinical characteristics of MA (attack frequency, aura length or type, disease history), vascular factors and the presence of right-to-left shunt on VMR. Diverging from our hypothesis, MA patients displayed a higher breath-holding index (BHI) than controls in the MCA (1.84±0.47%/s vs 1.53±0.47%/s, p = .001) as well as in the PCA (1.87±0.65%/s vs 1.47±0.44%/s, p < .001). In MA patients, MCA BHI was higher in those with large right-to-left shunts (2.09±0.42 vs 1.79±0.47, p = .046) and lower in those taking estrogens (1.30±0.30%/s vs 1.9±0.45%/s, p = .009). We did not observe an effect of MA characteristics on BHI. The increased BHI in MA patients with large right-to-left shunts could be explained by the vasoactive effect in the cerebral circulation of substances bypassing the deactivating pulmonary filters or by a constitutional trait of the vascular system associating persistent right-to-left shunts and hyper-reactive hemodynamics. Our results discourage the hypothesis that altered hemodynamics contribute to increasing the stroke risk in all MA patients. However, estrogens can lower VMR, curtailing the hemodynamic resources of MA patients.
| S-EPMC6675040 | biostudies-literature
Project description:Background:Both the age and number of endurance Masters athletes is increasing; this coincides with increasing cardiovascular risk. The vast majority of sports-related sudden cardiac deaths (SCDs) occur among athletes >35?years of age. Coronary artery disease (CAD) is the most common cause of SCD amongst Masters athletes. Case summary:In our prospective screening trial, six asymptomatic Masters athletes with ischaemia on electrocardiogram exercise stress testing had their coronary anatomy defined either by cardiac computed tomography or coronary angiography. Three patients underwent coronary angiography, with fractional flow reserve (FFR) testing performed when indicated. Subsequent percutaneous revascularization was performed in one patient after a shared-decision making process involving the patient and the referring cardiologist. All six athletes identified with obstructive CAD were male. The mean age and Framingham risk score was 61.8?years (±9.5) and 22.7% (±6.1), respectively. The mean metabolic equivalent of task achieved was 14.4 (±3.8). All athletes were treated with optimal medical therapy as clinically indicated. No cardiac events occured in 4.3 years of follow-up. Discussion:Guidelines recommend revascularization of Masters athletes to alleviate the ischaemic substrate despite a paucity of evidence that revascularization will translate into a reduction in myocardial infarct or sudden cardiac arrest/death. Herein, although a limited study population, we demonstrate a lack of clinical events after 4.3 years of follow-up whether or not revascularization was performed. A prospective multicentre registry for asymptomatic Masters athletes with documented obstructive CAD is needed to help establish the role of revascularization in this population.
| S-EPMC7319857 | biostudies-literature
Project description:Objective: Impaired cerebral blood flow (CBF) regulation, such as reduced reactivity to hypercapnia, contributes to the pathophysiology after aneurysmal subarachnoid hemorrhage (SAH), but temporal dynamics in the acute phase are unknown. Featuring comparable molecular regulation mechanisms, the retinal vessels participate in chronic and subacute stroke- and SAH-associated vessel alterations in patients and can be studied non-invasively. This study is aimed to characterize the temporal course of the cerebral and retinal vascular reactivity to hypercapnia in the acute phase after experimental SAH and compare the potential degree of impairment. Methods: Subarachnoid hemorrhage was induced by injecting 0.5 ml of heparinized autologous blood into the cisterna magna of male Wistar rats using two anesthesia protocols [isoflurane/fentanyl n = 25 (Sham + SAH): Iso-Group, ketamine/xylazine n = 32 (Sham + SAH): K/X-Group]. CBF (laser speckle contrast analysis) and physiological parameters were measured continuously for 6 h. At six predefined time points, hypercapnia was induced by hypoventilation controlled via blood gas analysis, and retinal vessel diameter (RVD) was determined non-invasively. Results: Cerebral reactivity and retinal reactivity in Sham groups were stable with only a slight attenuation after 2 h in RVD of the K/X-Group. In the SAH Iso-Group, cerebral and retinal CO2 reactivity compared to baseline was immediately impaired starting at 30 min after SAH (CBF p = 0.0090, RVD p = 0.0135) and lasting up to 4 h (p = 0.0136, resp. p = 0.0263). Similarly, in the K/X-Group, cerebral CO2 reactivity was disturbed early after SAH (30 min, p = 0.003) albeit showing a recovery to baseline after 2 h while retinal CO2 reactivity was impaired over the whole observation period (360 min, p = 0.0001) in the K/X-Group. After normalization to baseline, both vascular beds showed a parallel behavior regarding the temporal course and extent of impairment. Conclusion: This study provides a detailed temporal analysis of impaired cerebral vascular CO2 reactivity starting immediately after SAH and lasting up to 6 h. Importantly, the retinal vessels participate in these acute changes underscoring the promising role of the retina as a potential non-invasive screening tool after SAH. Further studies will be required to determine the correlation with functional outcomes.
| S-EPMC8793938 | biostudies-literature
Project description:Chronic hypertension induces cerebrovascular remodeling, changing the inner diameter and elasticity of arterial vessels. To examine cerebrovascular morphologic changes and vasodilatory impairment in early-stage hypertension, we measured baseline (normocapnic) cerebral arterial blood volume (CBV(a)) and cerebral blood flow (CBF) as well as hypercapnia-induced dynamic vascular responses in animal models. All experiments were performed with young (3 to 4 month old) spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats (WKY) under ∼1% isoflurane anesthesia at 9.4 Tesla. Baseline regional CBF values were similar in both animal groups, whereas SHR had significantly lower CBV(a) values, especially in the hippocampus area. As CBF is maintained by adjusting arterial diameters within the autoregulatory blood pressure range, CBV(a) is likely more sensitive than CBF for detecting hypertensive-mediated alterations. Unexpectedly, hypercapnia-induced CBF and blood-oxygenation-level-dependent (BOLD) response were significantly higher in SHR as compared with WKY, and the CBF reactivity was highly correlated with the BOLD reactivity in both groups. The higher reactivity in early-stage hypertensive animals indicates no significant vascular remodeling occurred. At later stages of hypertension, the reduced vascular reactivity is expected. Thus, CBF and CBV(a) mapping may provide novel insights into regional cerebrovascular impairment in hypertension and its progression as hypertension advances.
| S-EPMC3948115 | biostudies-other
Project description:Magnetic Particle Imaging (MPI) is a rapidly developing imaging modality that directly measures and maps the concentration of injected superparamagnetic iron oxide nanoparticles (SPIOs). Since the agent does not cross the blood-brain barrier, cerebral SPIO concentration provides a direct probe of Cerebral Blood Volume (CBV). Here we provide an initial demonstration of the ability of MPI to detect functional CBV changes (fCBV) by monitoring SPIO concentration during hypercapnic manipulation in a rat model. As a tracer detection method, MPI offers a more direct probe of agent concentration and therefore fCBV than MRI measurements in which the agent is indirectly detected through perturbation of water relaxation time constants such as T2?. We found that MPI detection could measure CBV changes during hypercapnia with high CNR (CNR?=?50) and potentially with high temporal resolution. Although the detection process more closely resembles a tracer method, we also identify evidence of physiological noise in the MPI time-series, with higher time-series variance at higher concentration levels. Our findings suggest that CBV-based MPI can provide a detection modality for hemodynamic changes. Further investigation with tomographic imaging is needed to assess tomographic ability of the method and further study the presence of time-series fluctuations which scale with signal level similar to physiological noise in resting fMRI time-courses.
| S-EPMC6344028 | biostudies-literature
Project description:Once the general decline in muscle mass, muscle strength and physical performance falls below specific thresholds, the middle aged or older adult will be diagnosed as having sarcopenia (a loss of skeletal muscle mass and strength). Sarcopenia contributes to a range of adverse events in older age including disability, hospitalisation, institutionalisation and falls. One potentially relevant but understudied population for sarcopenia researchers would be Masters athletes. Masters sport is becoming more common as it allows athletes (typically 40 years and older) the opportunity to participate in individual and/or team sports against individuals of similar age. This study examined a variety of measures of anthropometric, physical function and general health markers in the male and female Masters athletes who competed at the 2014 Pan Pacific Masters Games held on the Gold Coast, Australia. Bioelectrical impedance analysis was used to collect body fat percentage, fat mass and fat-free mass; with body mass, height, body mass index (BMI) and sarcopenic status also recorded. Physical function was quantified by handgrip strength and habitual walking speed; with general health described by the number of chronic diseases and prescribed medications. Between group analyses utilised ANOVA and Tukey's post-hoc tests to examine the effect of age group (40-49, 50-59, 60-69 and >70 years old) on the outcome measures for the entire sample as well as the male and female sub-groups. A total of 156 athletes (78 male, 78 female; mean 55.7 years) provided informed consent to participate in this study. These athletes possessed substantially better anthropometric, physical function and general health characteristics than the literature for their less physically active age-matched peers. No Masters athletes were categorised as being sarcopenic, although one participant had below normal physical performance and six participants had below normal muscle strength. In contrast, significant age-related reductions in handgrip strength and increases in the number of chronic diseases and prescribed medications were observed for the overall cohort as well as the male and female sub-groups. Nevertheless, even those aged over 70 years only averaged one chronic disease and one prescribed medication. These results may suggest that participation in Masters sport helps to maintain anthropometry, physical function and general health in middle-aged and older adults. However, it is also possible that only healthier middle-aged and older adults with favourable body composition and physical function may be able to participate in Masters sport. Future research should therefore utilise longitudinal research designs to determine the health and functional benefits of Master sports participation for middle-aged and older adults.
| S-EPMC5592080 | biostudies-literature
Project description:ObjectivesMyocardial fibrosis (MF) is associated with an increased predisposition to adverse cardiac events. The accumulation of high-volume and high-intensity exercise over an extended duration potentially increases the risk of MF. Specific electrocardiographic markers have been correlated with the presence of MF. This study assessed the prevalence of MF-related electrocardiographic markers in a Track and Field Master Athletics Cohort (TaFMAC).MethodsTwelve-lead resting electrocardiograms (ECGs) were conducted on 155 athletes (90 males and 65 females) participating in the World Masters Athletics 2022. The ECG markers associated with MF, including pathological Q waves, inverted T waves, fragmented QRS complex, and prolonged QRS complex, were compared among different athletic specialities (endurance athletes n=51, sprinters n=69 and strength and power n=35).ResultsOverall, 71 instances of MF-related markers were identified from 155 ECG recordings (46%). Fragmented QRS emerged as the most common marker, with a prevalence of 29% in endurance and strength and power athletes, and 35% in sprinters. No significant group differences were observed in the prevalence of MF markers, whether analysed collectively (p=0.467) or individually (pathological Q waves p=0.367, inverted T waves p=0.309, fragmented QRS complex p=0.747 and prolonged QRS complex p=0.132).ConclusionsThe prevalence of MF markers, as determined by resting ECG, was evident in nearly half of masters athletes, irrespective of sex and sporting specialisation. These findings suggest resting ECG as a promising non-invasive method for the early identification of MF in athlete's hearts.
| S-EPMC11367365 | biostudies-literature