The effects of multi-stage exercise with and without concurrent cognitive performance on cardiorespiratory and cerebral haemodynamic responses (original) (raw)
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European Journal of Applied Physiology, 2015
was monitored during the resting and exercise conditions over the prefrontal cortex (PFC) using near-infrared spectroscopy (NIRS). Results High-intensity exercise slowed RT in both the Naming (p = 0.04) and the Executive condition (p = 0.04). The analysis also revealed that high-intensity exercise was associated with a decreased accuracy when compared to low-intensity exercise (p = 0.021). Neuroimaging results confirm a decrease of cerebral oxygenation during highintensity exercise in comparison to low-(p = 0.004) and moderate-intensity exercise (p = 0.003). Correlations revealed that a lower cerebral HbO 2 in the prefrontal cortex was associated with slower RT in the Executive condition only (p = 0.04, g = −0.72). Conclusion Results of the present study suggest that low to moderate exercise intensity does not alter Executive functioning, but that exercise impairs cognitive functions (Executive and non-Executive) when the physical workload becomes heavy. The cerebral HbO 2 correlation suggests that a lower availability of HbO 2 was associated with slower RT in the Executive condition only. Keywords Reaction time • Near-infrared spectroscopy • Cerebral HbO 2 • Peak power output • Hyperventilation Abbreviations ANOVA Analysis of variance BMI Body mass index C0 2 Carbon dioxide CBF Cerebral blood flow CBF Cerebral blood flow fNIRS Functional near-infrared spectroscopy GLM General linear model HbO Oxy-hemoglobin HbR Deoxy-hemoglobin
Cerebral oxygenation decreases but does not impair performance during self-paced, strenuous exercise
Acta Physiologica, 2010
Aim: The reduction in cerebral oxygenation (Cox) is associated with the cessation of exercise during constant work rate and incremental tests to exhaustion. Yet in exercises of this nature, ecological validity is limited due to work rate being either fully or partly dictated by the protocol, and it is unknown whether cerebral deoxygenation also occurs during self-paced exercise. Here, we investigated the cerebral haemodynamics during a 5-km running time trial in trained runners. Methods: Rating of perceived exertion (RPE) and surface electromyogram (EMG) of lower limb muscles were recorded every 0.5 km. Changes in Cox (prefrontal lobe) were monitored via near-infrared spectroscopy through concentration changes in oxy-and deoxyhaemoglobin (D[O 2 Hb], D[HHb]). Changes in total Hb were calculated (D[THb] = D[O 2 Hb] + D[HHb]) and used as an index of change in regional blood volume. Results: During the trial, RPE increased from 6.6 AE 0.6 to 19.1 AE 0.7 indicating maximal exertion. Cox rose from baseline to 2.5 km (› D[O 2 Hb], › D[HHb], › D[THb]), remained constant between 2.5 and 4.5 km, and fell from 4.5 to 5 km (fl D[O 2 Hb], › D[HHb], M D[THb]
Cerebral Regulation in Different Maximal Aerobic Exercise Modes
Frontiers in Physiology, 2016
We investigated cerebral responses, simultaneously with peripheral and ratings of perceived exertion (RPE) responses, during different VO 2MAX-matched aerobic exercise modes. Nine cyclists (VO −1 −1 2MAX of 57.5 ± 6.2 ml•kg •min) performed a maximal, controlled-pace incremental test (MIT) and a self-paced 4 km time trial (TT 4km). Measures of cerebral (COX) and muscular (MOX) oxygenation were assessed throughout the exercises by changes in oxy-(O 2 Hb) and deoxy-hemoglobin (HHb) concentrations over the prefrontal cortex (PFC) and vastus lateralis (VL) muscle, respectively. Primary motor cortex (PMC) electroencephalography (EEG), VL, and rectus femoris EMG were also assessed throughout the trials, together with power output and cardiopulmonary responses. The RPE was obtained at regular intervals. Similar motor output (EMG and power output) occurred from 70% of the duration in MIT and TT 4km , despite the greater motor output, muscle deoxygenation (↓ MOX) and cardiopulmonary responses in TT 4km before that point. Regarding cerebral responses, there was a lower COX (↓ O 2 Hb concentrations in PFC) at 20, 30, 40, 50 and 60%, but greater at 100% of the TT 4km duration when compared to MIT. The alpha wave EEG in PMC remained constant throughout the exercise modes, with greater values in TT 4km. The RPE was maximal at the endpoint in both exercises, but it increased slower in TT 4km than in MIT. Results showed that similar motor output and effort tolerance were attained at the closing stages of different VO 2MAX-matched aerobic exercises, although the different disturbance until that point. Regardless of different COX responses during most of the exercises duration, activation in PMC was preserved throughout the exercises, suggesting that these responses may be part of a centrally-coordinated exercise regulation.
Brain and central haemodynamics and oxygenation during maximal exercise in humans
The Journal of Physiology, 2004
During maximal exercise in humans, fatigue is preceded by reductions in systemic and skeletal muscle blood flow, O 2 delivery and uptake. Here, we examined whether the uptake of O 2 and substrates by the human brain is compromised and whether the fall in stroke volume of the heart underlying the decline in systemic O 2 delivery is related to declining venous return. We measured brain and central haemodynamics and oxygenation in healthy males (n = 13 in 2 studies) performing intense cycling exercise (360 ± 10 W; mean ± s.e.m.) to exhaustion starting with either high (H) or normal (control, C) body temperature. Time to exhaustion was shorter in H than in C (5.8 ± 0.2 versus 7.5 ± 0.4 min, P < 0.05), despite heart rate reaching similar maximal values. During the first 90 s of both trials, frontal cortex tissue oxygenation and the arterial-internal jugular venous differences (a-v diff) for O 2 and glucose did not change, whereas middle cerebral artery mean flow velocity (MCA V mean) and cardiac output increased by ∼22 and ∼115%, respectively. Thereafter, brain extraction of O 2 , glucose and lactate increased by ∼45, ∼55 and ∼95%, respectively, while frontal cortex tissue oxygenation, MCA V mean and cardiac output declined ∼40, ∼15 and ∼10%, respectively. At exhaustion in both trials, systemicV O 2 declined in parallel with a similar fall in stroke volume and central venous pressure; yet the brain uptake of O 2 , glucose and lactate increased. In conclusion, the reduction in stroke volume, which underlies the fall in systemic O 2 delivery and uptake before exhaustion, is partly related to reductions in venous return to the heart. Furthermore, fatigue during maximal exercise, with or without heat stress, in healthy humans is associated with an enhanced rather than impaired brain uptake of O 2 and substrates.
The differential effects of prolonged exercise upon executive function and cerebral oxygenation
Brain and cognition, 2017
The acute-exercise effects upon cognitive functions are varied and dependent upon exercise duration and intensity, and the type of cognitive tasks assessed. The hypofrontality hypothesis assumes that prolonged exercise, at physiologically challenging intensities, is detrimental to executive functions due to cerebral perturbations (indicated by reduced prefrontal activity). The present study aimed to test this hypothesis by measuring oxygenation in prefrontal and motor regions using near-infrared spectroscopy during two executive tasks (flanker task and 2-back task) performed while cycling for 60min at a very low intensity and an intensity above the ventilatory threshold. Findings revealed that, compared to very low intensity, physiologically challenging exercise (i) shortened reaction time in the flanker task, (ii) impaired performance in the 2-back task, and (iii) initially increased oxygenation in prefrontal, but not motor regions, which then became stable in both regions over tim...
Hemodynamic changes in athletes’ brains: is there any adaptation?
General physiology and biophysics, 2021
This study compared the hemodynamic changes in the prefrontal cortex during sprint interval training (SIT) and recovery periods in sedentary and athletes. SIT was performed on a cycling ergometer on 12 male athletes and 9 sedentary participants. A functional near-infrared spectroscopy (fNIRS) device was used to record the hemodynamic changes of the prefrontal cortex throughout the protocol. The oxyhemoglobin (Oxy-Hb) levels in the prefrontal cortex were increased significantly, and the power outputs were decreased in repetitive Wingate anaerobic tests (WAnTs) in Sedentary and Athletes group (p < 0.001). In addition, the Sedentary group had higher Oxy-Hb values (p < 0.001). However, the recovery times decreased significantly after all WAnTs (p < 0.05). Despite the increased fatigue, athletes performed better with less Oxy-Hb than the sedentary participants. Also, the recovery of the Oxy-Hb values in the prefrontal region was faster in athletes. These results may highlight a possible brain adaptation in athletes.
2018
Cardiovascular activities may increase the brain blood flow improving neuronal activities leading to improved cognition. Consequently, the effects of an acute bout of moderate intensity aerobic exercise on brain hemodynamics and its correlation with cognitive color-word Stroop task performance were tested. The Stroop tasks were congruent (color matches word) and incongruent (color does not match word). Prefrontal (PFC) and motor cortex (MC) blood flow was recorded by fNIRS (functional near-infrared spectroscopy) while the subject was performing the Stroop tasks before and after the 30 minutes of exercise or equivalent time of rest controls (checking for practice effects). Ninety human subjects of age 24± 6, 20 ADHD (attention-deficit hyper-activity disorder), 27 High-BMI (>25), 29 males were recruited. Reaction time ‘RT' decreased (p<0.05) after exercise for both the congruent (12%) and incongruent (10%) Stroop tasks, compared to 8% with practice alone. Accuracy did not ch...
Experimental Gerontology, 2012
Regular exercise improves the age-related decline in cerebral blood flow (CBF) and is associated with improved cognitive function; however, less is known about the direct relationship between CBF and cognitive function. We examined the influence of healthy aging on the capability of acute exercise to improve cognition, and whether exercise-induced improvements in cognition are related to CBF and cortical hemodynamics. Middle cerebral artery blood flow velocity (MCAv; Doppler) and cortical hemodynamics (NIRS) were measured in 13 young (24 ± 5 y) and 9 older (62 ± 3 y) participants at rest and during cycling at 30% and 70% of heart rate range (HRR). Cognitive performance was assessed using a computer-adapted Stroop task (i.e., test of executive function cognition) at rest and during exercise. Average response times on the Stroop task were slower for the older compared to younger group for both simple and difficult tasks (P b 0.01). Independent of age, difficult-task response times improved during exercise (P b 0.01), with the improvement greater at 70% HRR exercise (P = 0.04 vs. 30% HRR). Higher MCAv was correlated with faster response times for simple and difficult tasks at rest (R 2 =0.47 and R 2 = 0.47, respectively), but this relation uncoupled progressively during exercise. Exercise-induced increases in MCAv were similar and unaltered during cognitive tasks for both age groups. In contrast, prefrontal cortical hemodynamic NIRS measures [oxyhemoglobin (O 2 Hb) and total hemoglobin (tHb)] were differentially affected by exercise intensity, age and cognitive task; e.g., there were smaller increases in [O 2 Hb] and [tHb] in the older group between exercise intensities (P b 0.05). These data indicate that: 1) Regardless of age, cognitive (executive) function is improved while exercising; 2) while MCAv is strongly related to cognition at rest, this relation becomes uncoupled during exercise, and 3) there is dissociation between global CBF and regional cortical oxygenation and NIRS blood volume markers during exercise and engagement of prefrontal cognition.
Cerebral blood flow and metabolism during exercise: implications for fatigue
Journal of Applied Physiology, 2007
Secher NH, Seifert T, Van Lieshout JJ. Cerebral blood flow and metabolism during exercise, implications for fatigue. During exercise: the Kety-Schmidt-determined cerebral blood flow (CBF) does not change because the jugular vein is collapsed in the upright position. In contrast, when CBF is evaluated by 133 Xe clearance, by flow in the internal carotid artery, or by flow velocity in basal cerebral arteries, a ϳ25% increase is detected with a parallel increase in metabolism. During activation, an increase in cerebral O 2 supply is required because there is no capillary recruitment within the brain and increased metabolism becomes dependent on an enhanced gradient for oxygen diffusion. During maximal whole body exercise, however, cerebral oxygenation decreases because of eventual arterial desaturation and marked hyperventilation-related hypocapnia of consequence for CBF. Reduced cerebral oxygenation affects recruitment of motor units, and supplemental O 2 enhances cerebral oxygenation and work capacity without effects on muscle oxygenation. Also, the work of breathing and the increasing temperature of the brain during exercise are of importance for the development of so-called central fatigue. During prolonged exercise, the perceived exertion is related to accumulation of ammonia in the brain, and data support the theory that glycogen depletion in astrocytes limits the ability of the brain to accelerate its metabolism during activation. The release of interleukin-6 from the brain when exercise is prolonged may represent a signaling pathway in matching the metabolic response of the brain. Preliminary data suggest a coupling between the circulatory and metabolic perturbations in the brain during strenuous exercise and the ability of the brain to access slow-twitch muscle fiber populations.