Noninvasive estimation of microvascular O2 provision during exercise on-transients in healthy young males

2012 ◽  
Vol 303 (8) ◽  
pp. R815-R823 ◽  
Author(s):  
Juan M. Murias ◽  
Matthew D. Spencer ◽  
Silvia Pogliaghi ◽  
Donald H. Paterson
Keyword(s):  
Amplitude Ratio ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Young Males ◽  
Noninvasive Estimation ◽  
Response Profiles ◽  
Priming Exercise ◽  
Fick Equation ◽  
Exponential Response

Two methods for estimating changes in microvascular O2 delivery during the on-transient of exercise were evaluated. They were tested to assess the role of the adjustment of the estimated microvascular O2 delivery in the speeding of V̇o2 kinetics during a Mod1-Hvy-Mod2 protocol (Mod, moderate-intensity exercise; Hvy, heavy-intensity “priming” exercise), in which Mod2 is preceded by a bout of Hvy. Mod pulmonary V̇o2 (V̇o2p) and deoxy-hemoglobin [HHb] data were collected in 12 males (23 ± 3 yr); response profiles were fit with a monoexponential. Signals were also 1) scaled to a relative % of the response (0–100%) to calculate the [HHb]/V̇o2 ratio for each individual and 2) rearranged in the Fick equation for estimation of capillary blood flow (Qcap). A transient [HHb]/V̇o2 “overshoot” observed in Mod1 (1.06 ± 0.05; P < 0.05) was absent during Mod2 (1.01 ± 0.06; P > 0.05); reductions in the [HHb]/V̇o2 ratio (Mod1 − Mod2) were related to reductions in phase II τV̇o2p ( r = 0.82; P < 0.05). For Qcap, a near-exponential response was observed in 8/12 subjects in Mod1 and only in 4/12 subjects in Mod2. The Qcap profile was shown to be highly dependent on the [HHb] baseline-to-amplitude ratio. Thus, accurate and physiologically consistent estimations of Qcap were not possible in most cases. This study confirmed that priming exercise results in an improved O2 delivery as shown by the decreased [HHb]/V̇o2 ratio that was related to the smaller τV̇o2 in Mod2. Additionally, this study suggested that Qcap analysis may not be valid and should be interpreted with caution when assessing microvascular delivery of O2.

Speeding of V̇o2 kinetics during moderate-intensity exercise subsequent to heavy-intensity exercise is associated with improved local O2 distribution

2011 ◽  
Vol 111 (5) ◽  
pp. 1410-1415 ◽  
Author(s):  
Juan M. Murias ◽  
Matthew D. Spencer ◽  
Darren S. DeLorey ◽  
Brendon J. Gurd ◽  
John M. Kowalchuk ◽  
...  
Keyword(s):  
Phase Ii ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Moderate Intensity Exercise ◽  
Young Males ◽  
Monoexponential Model ◽  
O2 Distribution ◽  
Priming Exercise

The relationship between the adjustment of muscle deoxygenation (Δ[HHb]) and phase II VO2p during moderate-intensity exercise was examined before (Mod 1) and after (Mod 2) a bout of heavy-intensity “priming” exercise. Moderate intensity VO2p and Δ[HHb] kinetics were determined in 18 young males (26 ± 3 yr). VO2p was measured breath-by-breath. Changes in Δ[HHb] of the vastus lateralis muscle were measured by near-infrared spectroscopy. VO2p and Δ[HHb] response profiles were fit using a monoexponential model, and scaled to a relative % of the response (0–100%). The Δ[HHb]/V̇o2 ratio for each individual (reflecting the local matching of O2 delivery to O2 utilization) was calculated as the average Δ[HHb]/V̇o2 response from 20 s to 120 s during the exercise on-transient. Phase II τVO2p was reduced in Mod 2 compared with Mod 1 ( P < 0.05). The effective τ′Δ[HHb] remained the same in Mod 1 and Mod 2 ( P > 0.05). During Mod 1, there was an “overshoot” in the Δ[HHb]/V̇o2 ratio (1.08; P < 0.05) that was not present during Mod 2 (1.01; P > 0.05). There was a positive correlation between the reduction in the Δ[HHb]/V̇o2 ratio and the smaller τVO2p from Mod 1 to Mod 2 ( r = 0.78; P < 0.05). This study showed that a smaller τVO2p during a moderate bout of exercise subsequent to a heavy-intensity priming exercise was associated with improved microvascular O2 delivery during the on-transient of exercise, as suggested by a smaller Δ[HHb]/V̇o2 ratio.

Physical exercise and blood pressure with reference to the angiotensinogen M235T polymorphism

2002 ◽  
Vol 10 (2) ◽  
pp. 71-77 ◽  
Author(s):  
Rainer Rauramaa ◽  
Raimo Kuhanen ◽  
Timo A. Lakka ◽  
Sari B. Väisänen ◽  
Pirjo Halonen ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Reference Group ◽  
Controlled Trial ◽  
Exercise Group ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Blood Pressures ◽  
Agt Gene ◽  
M235t Polymorphism

We investigated the role of the angiotensinogen (AGT) gene M235T polymorphism in determining blood pressure (BP) response to moderate intensity exercise in a 6-yr randomized controlled trial in 140 middle-aged men. Sitting, supine, and standing blood pressures were measured annually. Of the randomized men, 86% participated in the trial for 6 yr. Submaximal cardiorespiratory fitness increased by 16% in the exercise group. In the M homozygotes, sitting systolic BP decreased by 1.0 mmHg in the exercise but increased by 14.6 mmHg in the reference group ( P = 0.007 for net effect). Sitting and supine diastolic BP decreased by 6.2 and 3.3 mmHg in the exercise but increased by 2.8 and 3.2 mmHg in the reference group ( P = 0.026 and 0.024 for net effects), respectively. Regular moderate intensity exercise attenuates aging-related increase in systolic BP and decreases diastolic BP among the M homozygotes of the AGT gene M235T polymorphism.

Effects of priming exercise on the speed of adjustment of muscle oxidative metabolism at the onset of moderate-intensity step transitions in older adults

2012 ◽  
Vol 302 (10) ◽  
pp. R1158-R1166 ◽  
Author(s):  
Gabriela De Roia ◽  
Silvia Pogliaghi ◽  
Alessandra Adami ◽  
Christina Papadopoulou ◽  
Carlo Capelli
Keyword(s):  
Older Adults ◽  
Cardiac Output ◽  
Oxidative Metabolism ◽  
Functional Decline ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Healthy Older Adults ◽  
Speed Of Adjustment ◽  
Priming Exercise ◽  
Kinetics Of

Aging is associated with a functional decline of the oxidative metabolism due to progressive limitations of both O2 delivery and utilization. Priming exercise (PE) increases the speed of adjustment of oxidative metabolism during successive moderate-intensity transitions. We tested the hypothesis that such improvement is due to a better matching of O2 delivery to utilization within the working muscles. In 21 healthy older adults (65.7 ± 5 yr), we measured contemporaneously noninvasive indexes of the overall speed of adjustment of the oxidative metabolism (i.e., pulmonary V̇o2 kinetics), of the bulk O2 delivery (i.e., cardiac output), and of the rate of muscle deoxygenation (i.e., deoxygenated hemoglobin, HHb) during moderate-intensity step transitions, either with (ModB) or without (ModA) prior PE. The local matching of O2 delivery to utilization was evaluated by the ΔHHb/ΔV̇o2 ratio index. The overall speed of adjustment of the V̇o2 kinetics was significantly increased in ModB compared with ModA ( P < 0.05). On the contrary, the kinetics of cardiac output was unaffected by PE. At the muscle level, ModB was associated with a significant reduction of the “overshoot” in the ΔHHb/ΔV̇o2 ratio compared with ModA ( P < 0.05), suggesting an improved O2 delivery. Our data are compatible with the hypothesis that, in older adults, PE, prior to moderate-intensity exercise, beneficially affects the speed of adjustment of oxidative metabolism due to an acute improvement of the local matching of O2 delivery to utilization.

scholarly journals Effect of P2 receptor blockade on cutaneous vasodilation during rest and exercise in the heat in young men

2018 ◽  
Vol 43 (3) ◽  
pp. 312-315
Author(s):  
Naoto Fujii ◽  
Robert D. Meade ◽  
Jeffrey C. Louie ◽  
Pegah Akbari ◽  
Pierre Boulay ◽  
...  
Keyword(s):  
Heat Exposure ◽  
P2 Receptors ◽  
Moderate Intensity ◽  
Receptor Blockade ◽  
P2 Receptor ◽  
Moderate Intensity Exercise ◽  
Cutaneous Vasodilation ◽  
Oxide Synthase ◽  
Rest And Exercise

We assessed the role of purinergic P2 receptors in the regulation of cutaneous vasodilation in young adults at rest and during intermittent moderate-intensity exercise in the heat (35 °C). P2 receptor blockade augmented resting cutaneous vasodilation but had no influence during and following exercise. This increase was partly diminished by nitric oxide synthase inhibition. These results suggest a functional role of P2 receptors in the regulation of cutaneous vascular tone during ambient heat exposure at rest.

scholarly journals Treatment strategies for chemotherapy-induced peripheral neuropathy: potential role of exercise

2011 ◽  
Vol 4 (2) ◽  
pp. 117
Author(s):  
Karen Y. Wonders ◽  
Beverly S. Reigle ◽  
Daniel G. Drury
Keyword(s):  
Quality Of Life ◽  
Peripheral Neuropathy ◽  
Cancer Patients ◽  
Lifestyle Modification ◽  
Treatment Strategies ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Exercise Rehabilitation

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, dose-limiting effect of cancer therapy that often has negative implications on a patient’s quality of life. The pain associated with CIPN has long been recognized as one of the most difficult types of pain to treat. Historically, much effort has been made to explore pharmacological therapies aimed at reducing symptoms of CIPN. While many of these agents provide a modest relief in the symptoms of peripheral neuropathy, many have been shown to have additional negative side effects for cancer patients. Therefore, the authors suggest exercise rehabilitation as one lifestyle modification that may positively impact the lives of patients with CIPN. To our knowledge, there are currently no published clinical trials examining the role of exercise in preserving neurological function following chemotherapy. However, investigations using low-to-moderate intensity exercise as an intervention in patients with diabetic peripheral neuropathy and hereditary motor and sensory neuropathies have produced promising results. Given that cancer patients appear to tolerate exercise, it seems plausible that exercise rehabilitation could be used as an effective strategy to minimize CIPN-induced detriments to quality of life.

scholarly journals EXERCISE ACUTELY IMPROVES COGNITION IN HEALTHY OLDER ADULTS: THE ROLE OF AROUSAL

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S836-S836
Author(s):  
Pearl N Cummins ◽  
James Kent ◽  
Timothy Weng ◽  
Vincent Magnottta ◽  
Gary Pierce ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Aerobic Exercise ◽  
Sympathetic Activity ◽  
Cognitive Task ◽  
Controlled Trial ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Back Task

Abstract Previous researchers have reported that aerobic exercise improves cognition in older adults; however, few researchers have examined the role of arousal on improvements in cognition after exercise. The purpose of this study was to understand how changes in arousal acutely affect changes in cognitive performance after a single session of light compared to moderate intensity aerobic exercise. Cognitively normal older adults (N = 34) were enrolled in a randomized controlled trial where they were asked to complete the N-back task with faces, a cognitive task used to test working memory, in an fMRI scanner. On separate days, the task was completed before and 15 to 20 minutes after light and moderate intensity exercise. An intervention was also completed, but our question focuses on the acute effects of exercise rather than training. Arousal was measured before and after exercise through a questionnaire and a direct measure of physiological activation of the sympathetic nervous system with galvanic skin response (GSR). On average, resting GSRs decreased from pre- to post-exercise scan; however, the change was not statistically significant. The decrease in arousal after light exercise indicated that older adults had decreased sympathetic activity after both light and moderate intensity exercise. By contrast, N-back task performance improved most after moderate compared to light intensity exercise. Together, evidence that sympathetic activity tended to decrease generally for both intensities, whereas cognitive improvements were more specific, suggests that changes in arousal at rest were not a critical factor connecting exercise and improved working memory in this study.

Regulation of V̇o2 kinetics by O2 delivery: insights from acute hypoxia and heavy-intensity priming exercise in young men

2012 ◽  
Vol 112 (6) ◽  
pp. 1023-1032 ◽  
Author(s):  
Matthew D. Spencer ◽  
Juan M. Murias ◽  
Tyler M. Grey ◽  
Donald H. Paterson
Keyword(s):  
Near Infrared ◽  
Acute Hypoxia ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Muscle Deoxygenation ◽  
V̇o2 Kinetics ◽  
Leg Cycling ◽  
Priming Exercise ◽  
The Individual ◽  
O2 Delivery

This study examined the separate and combined effects of acute hypoxia (Hypo) and heavy-intensity “priming” exercise (Hvy) on pulmonary O2 uptake (V̇o2p) kinetics during moderate-intensity exercise (Mod). Breath-by-breath V̇o2p and near-infrared spectroscopy-derived muscle deoxygenation {deoxyhemoglobin concentration [HHb]} were monitored continuously in 10 men (23 ± 4 yr) during repetitions of a Mod 1-Hvy-Mod 2 protocol, where each of the 6-min (Mod or Hvy) leg-cycling bouts was separated by 6 min at 20 W. Subjects were exposed to Hypo [fraction of inspired O2 (FiO2) = 15%, Mod 2 + Hypo] or “sham” (FiO2 = 20.9%, Mod 2-N) 2 min following Hvy in half of these repetitions; Mod was also performed in Hypo without Hvy (Mod 1 + Hypo). On-transient V̇o2p and [HHb] responses were modeled as a monoexponential. Data were scaled to a relative percentage of the response (0–100%), the signals were time-aligned, and the individual [HHb]-to-V̇o2 ratio was calculated. Compared with control (Mod 1), τV̇o2p and the O2 deficit (26 ± 7 s and 638 ± 144 ml, respectively) were reduced ( P < 0.05) in Mod 2-N (20 ± 5 s and 529 ± 196 ml) and increased ( P < 0.05) in Mod 1 + Hypo (34 ± 14 s and 783 ± 184 ml); in Mod 2 + Hypo, τV̇o2p was increased (30 ± 8 s, P < 0.05), yet O2 deficit was unaffected (643 ± 193 ml, P > 0.05). The modest “overshoot” in the [HHb]-to-V̇o2 ratio (reflecting an O2 delivery-to-utilization mismatch) in Mod 1 (1.06 ± 0.04) was abolished in Mod 2-N (1.00 ± 0.05), persisted in Mod 2 + Hypo (1.09 ± 0.07), and tended to increase in Mod 1 + Hypo (1.10 ± 0.09, P = 0.13). The present data do not support an “O2 delivery-independent” speeding of τV̇o2p following Hvy (or Hvy + Hypo); rather, this study suggests that local muscle O2 delivery likely governs the rate of adjustment of V̇o2 at τV̇o2p greater than ∼20 s.

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