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Influence of developmental nicotine exposure on the ventilatory and metabolic response to hyperthermia

Jonathan Ferng Ralph F. Fregosi 《The Journal of physiology》2015,593(23):5201-5213

AbstractTo determine whether developmental nicotine exposure (DNE) alters the ventilatory and metabolic response to hyperthermia in neonatal rats (postnatal age 2–4 days), pregnant dams were exposed to nicotine (6 mg kg⁻¹ of nicotine tartrate daily) or saline with an osmotic mini‐pump implanted subdermally on day 5 of gestation. Rat pups (a total of 72 controls and 72 DNE pups) were studied under thermoneutral conditions (chamber temperature 33°C) and during moderate thermal stress (37.5°C). In all pups, core temperature was similar to chamber temperature, with no treatment effects. The rates of pulmonary ventilation (

{\dot{V}}_{I}

), O₂ consumption (

{\dot{V}}_{O_{2}}

) and CO₂ production (

{\dot{V}}_{C O_{2}}

) did not change with hyperthermia in either control or DNE pups. However,

{\dot{V}}_{I}

was lower in DNE pups at both chamber temperatures, whereas the duration of spontaneous apnoeas was longer in DNE pups than in controls at 33°C. The

{\dot{V}}_{I}

{\dot{V}}_{O_{2}}

ratio increased at 37.5°C in control pups, although it did not change in DNE pups. To simulate severe thermal stress, additional pups were studied at 33°C and 43°C.

{\dot{V}}_{I}

increased with heating in control pups but not in DNE pups. As heat stress continued, gasping was evoked in both groups, with no effect of DNE on the gasping pattern. Over a 20 min recovery period at 33°C,

{\dot{V}}_{I}

returned to baseline in control pups but remained depressed in DNE pups. In addition to altering baseline

{\dot{V}}_{I}

and apnoea duration, DNE is associated with subtle but significant alterations in the ventilatory response to hyperthermia in neonatal rats.

Abbreviations

DNE: developmental nicotine exposure
P: postnatal day
RER: respiratory exchange ratio
T_chamber: chamber temperature
T_core: core temperature
${\dot{V}}_{I}$: pulmonary ventilation rate
${\dot{V}}_{O_{2}}$: oxygen consumption rate
${\dot{V}}_{C O_{2}}$: carbon dioxide production rate
V_T: tidal volume

相似文献

Limitations to oxygen transport and utilization during sprint exercise in humans: evidence for a functional reserve in muscle O2 diffusing capacity

José A. L. Calbet José Losa‐Reyna Rafael Torres‐Peralta Peter Rasmussen Jesús Gustavo Ponce‐González A. William Sheel Jaime de la Calle‐Herrero Amelia Guadalupe‐Grau David Morales‐Alamo Teresa Fuentes Lorena Rodríguez‐García Christoph Siebenmann Robert Boushel Carsten Lundby 《The Journal of physiology》2015,593(20):4649-4664

Key points

Severe acute hypoxia reduces sprint performance.
Muscle ${\dot{V}}_{O_{2}}$ during sprint exercise in normoxia is not limited by O₂ delivery, O₂ offloading from haemoglobin or structure‐dependent diffusion constraints in the skeletal muscle of young healthy men.
A large functional reserve in muscle O₂ diffusing capacity exists and remains available at exhaustion during exercise in normoxia; this functional reserve is recruited during exercise in hypoxia.
During whole‐body incremental exercise to exhaustion in severe hypoxia, leg ${\dot{V}}_{O_{2}}$ is primarily dependent on convective O₂ delivery and less limited by diffusion constraints than previously thought.
The kinetics of O₂ offloading from haemoglobin does not limit ${\dot{V}}_{O_{2} peak}$ in hypoxia.
Our results indicate that the limitation to ${\dot{V}}_{O_{2}}$ during short sprints resides in mechanisms regulating mitochondrial respiration.

Abstract

To determine the contribution of convective and diffusive limitations to

{\dot{V}}_{O_{2} peak}

during exercise in humans, oxygen transport and haemodynamics were measured in 11 men (22 ± 2 years) during incremental (IE) and 30 s all‐out cycling sprints (Wingate test, WgT), in normoxia (Nx, P_IO₂: 143 mmHg) and hypoxia (Hyp, P_IO₂: 73 mmHg). Carboxyhaemoglobin (COHb) was increased to 6–7% before both WgTs to left‐shift the oxyhaemoglobin dissociation curve. Leg

{\dot{V}}_{O_{2}}

was measured by the Fick method and leg blood flow (BF) with thermodilution, and muscle O₂ diffusing capacity (D_MO₂) was calculated. In the WgT mean power output, leg BF, leg O₂ delivery and leg

{\dot{V}}_{O_{2}}

were 7, 5, 28 and 23% lower in Hyp than Nx (P < 0.05); however, peak WgT D_MO₂ was higher in Hyp (51.5 ± 9.7) than Nx (20.5 ± 3.0 ml min⁻¹ mmHg⁻¹, P < 0.05). Despite a similar P_aO₂ (33.3 ± 2.4 and 34.1 ± 3.3 mmHg), mean capillary P_O₂ (16.7 ± 1.2 and 17.1 ± 1.6 mmHg), and peak perfusion during IE and WgT in Hyp, D_MO₂ and leg

{\dot{V}}_{O_{2}}

were 12 and 14% higher, respectively, during WgT than IE in Hyp (both P < 0.05). D_MO₂ was insensitive to COHb (COHb: 0.7 vs. 7%, in IE Hyp and WgT Hyp). At exhaustion, the Y equilibration index was well above 1.0 in both conditions, reflecting greater convective than diffusive limitation to the O₂ transfer in both Nx and Hyp. In conclusion, muscle

{\dot{V}}_{O_{2}}

during sprint exercise is not limited by O₂ delivery, O₂ offloading from haemoglobin or structure‐dependent diffusion constraints in the skeletal muscle. These findings reveal a remarkable functional reserve in muscle O₂ diffusing capacity.

Abbreviations

a‐vO₂diff: arteriovenous oxygen concentration difference
BF: blood flow
C_aO₂: arterial content of oxygen
CO: carbon monoxide
COHb: carboxyhaemoglobin
D_LO₂: lung O₂ diffusing capacity
D_MO₂: muscle O₂ diffusing capacity
D_O₂: O₂ diffusing capacity
ECG: electrocardiogram
F_IO₂: inspired oxygen fraction
FV: femoral vein
HR_max: maximal heart rate
HR_peak: peak heart rate during Wingate
Hyp: hypoxia
LBF: leg blood flow
Nx: normoxia
S_O₂: haemoglobin saturation with O₂
ODC: oxyhaemoglobin dissociation curve
P₅₀: partial oxygen pressure at 50% S_O₂
P_aO₂: arterial oxygen pressure
P_CO₂: carbon dioxide pressure
P_O₂: oxygen pressure
P_{O₂ cap}: capillary O₂ pressure
P_{O₂ mit}: mitochondrial O₂ pressure
P_{FV O₂}: femoral vein P_O₂
P_IO₂: inspiratory O₂ pressure
${\dot{V}}_{C O_{2}}$: carbon dioxide production
${\dot{V}}_{C O_{2} peak}$: peak carbon dioxide production
${\dot{V}}_{Epeak}$: peak pulmonary ventilation
${\dot{V}}_{O_{2}}$: oxygen consumption
${\dot{V}}_{O_{2} \max}$: maximal oxygen consumption
${\dot{V}}_{O_{2} peak}$: peak oxygen uptake
W_peak‐i: instantaneous peak power output
W_mean‐10: mean power output during the first 10 s of the sprint exercise
W_mean‐30: mean power output during the whole sprint exercise
WgT: isokinetic 30 s Wingate test

相似文献

Symmorphosis and skeletal muscle V˙O2 max : in vivo and in vitro measures reveal differing constraints in the exercise‐trained and untrained human

Jayson R. Gifford Ryan S. Garten Ashley D. Nelson Joel D. Trinity Gwenael Layec Melissa A. H. Witman Joshua C. Weavil Tyler Mangum Corey Hart Cory Etheredge Jake Jessop Amber Bledsoe David E. Morgan D. Walter Wray Matthew J. Rossman Russell S. Richardson 《The Journal of physiology》2016,594(6):1741-1751

Key points

The concept of symmorphosis predicts that the capacity of each step of the oxygen cascade is attuned to the task demanded of it during aerobic exercise at maximal rates of oxygen consumption ( ${\dot{V}}_{O_{2} \max}$ ) such that no single process is limiting or in excess at ${\dot{V}}_{O_{2} \max}$ .
The present study challenges the applicability of this concept to humans by revealing clear, albeit very different, limitations and excesses in oxygen supply and consumption among untrained and endurance‐trained humans.
Among untrained individuals, ${\dot{V}}_{O_{2} \max}$ is limited by the capacity of the mitochondria to consume oxygen, despite an excess of oxygen supply, whereas, among trained individuals, ${\dot{V}}_{O_{2} \max}$ is limited by the supply of oxygen to the mitochondria, despite an excess of mitochondrial respiratory capacity.

Abstract

The concept of symmorphosis postulates a matching of structural capacity to functional demand within a defined physiological system, regardless of endurance exercise training status. Whether this concept applies to oxygen (O₂) supply and demand during maximal skeletal muscle O₂ consumption (

{\dot{V}}_{O_{2} \max}

) in humans is unclear. Therefore, in vitro skeletal muscle mitochondrial

{\dot{V}}_{O_{2} \max}

(_Mito

{\dot{V}}_{O_{2} \max}

, mitochondrial respiration of fibres biopsied from vastus lateralis) was compared with in vivo skeletal muscle

{\dot{V}}_{O_{2} \max}

during single leg knee extensor exercise (_KE

{\dot{V}}_{O_{2} \max}

, direct Fick by femoral arterial and venous blood samples and Doppler ultrasound blood flow measurements) and whole‐body

{\dot{V}}_{O_{2} \max}

during cycling (_Body

{\dot{V}}_{O_{2} \max}

, indirect calorimetry) in 10 endurance exercise‐trained and 10 untrained young males. In untrained subjects, during KE exercise, maximal O₂ supply (_KE

\dot{Q}

O_2max) exceeded (462 ± 37 ml kg⁻¹ min⁻¹, P < 0.05) and _KE

{\dot{V}}_{O_{2} \max}

matched (340 ± 22 ml kg⁻¹ min⁻¹, P > 0.05) _Mito

{\dot{V}}_{O_{2} \max}

(364 ± 16 ml kg⁻¹ min⁻¹). Conversely, in trained subjects, both _KE

\dot{Q}

O_2max (557 ± 35 ml kg⁻¹ min⁻¹) and _KE

{\dot{V}}_{O_{2} \max}

(458 ± 24 ml kg⁻¹ min⁻¹) fell far short of _Mito

{\dot{V}}_{O_{2} \max}

(743 ± 35 ml kg⁻¹ min⁻¹, P < 0.05). Although _Mito

{\dot{V}}_{O_{2} \max}

was related to _KE

{\dot{V}}_{O_{2} \max}

(r = 0.69, P < 0.05) and _Body

{\dot{V}}_{O_{2} \max}

(r = 0.91, P < 0.05) in untrained subjects, these variables were entirely unrelated in trained subjects. Therefore, in untrained subjects,

{\dot{V}}_{O_{2} \max}

is limited by mitochondrial O₂ demand, with evidence of adequate O₂ supply, whereas, in trained subjects, an exercise training‐induced mitochondrial reserve results in skeletal muscle

{\dot{V}}_{O_{2} \max}

being markedly limited by O₂ supply. Taken together, these in vivo and in vitro measures reveal clearly differing limitations and excesses at

{\dot{V}}_{O_{2} \max}

in untrained and trained humans and challenge the concept of symmorphosis as it applies to O₂ supply and demand in humans. 相似文献

Higher oesophageal temperature at rest and during exercise in humans with patent foramen ovale

James T. Davis Chi‐Yan A. Ng Sierra D. Hill Richard C. Padgett Andrew T. Lovering 《The Journal of physiology》2015,593(20):4615-4630

Key points

Patent foramen ovale (PFO) is present in ∼35% of the general population.
The respiratory system participates in thermoregulation via evaporative and convective heat loss so blood flow that bypasses the respiratory system, e.g. through a PFO, may not participate in respiratory system cooling.
We found that subjects with a PFO (PFO+) had a ∼0.4°C higher oesophageal temperature (T _oesoph) than subjects without a PFO (PFO−) during pre‐exercise and exercise.
T _oesoph in PFO+ subjects was associated with the estimated size of the PFO whereby subjects with a large PFO had a greater T _oesoph than PFO− subjects and subjects with a small PFO.
During high intensity exercise breathing cold and dry air, PFO+ subjects achieved a higher T _oesoph than PFO– subjects.
Absence of respiratory system cooling of shunted blood partially explains the differences in T _oesoph between PFO+ and PFO– subjects; other differences in thermoregulatory responses that impact core temperature also likely exist.

Abstract

Respiratory system cooling occurs via convective and evaporative heat loss, so right‐to‐left shunted blood flow through a patent foramen ovale (PFO) would not be cooled. Accordingly, we hypothesized that PFO+ subjects would have a higher core temperature than PFO– subjects due, in part, to absence of respiratory system cooling of the shunted blood and that this effect would be dependent upon the estimated PFO size and inspired air temperature. Subjects were screened for the presence and size of a PFO using saline contrast echocardiography. Thirty well‐matched males (15 PFO−, 8 large PFO+, 7 small PFO+) completed cycle ergometer exercise trials on three separate days. During Trial 1, subjects completed a

{\dot{V}}_{O_{2} \max}

test. For Trials 2 and 3, randomized, subjects completed four 2.5 min stages at 25, 50, 75 and 90% of the maximum workload achieved during Trial 1, breathing either ambient air (20.6 ± 1.0°C) or cold air (1.9 ± 3.5°C). PFO+ subjects had a higher oesophageal temperature (T _oesoph) (P < 0.05) than PFO− subjects on Trial 1. During exercise breathing cold and dry air, PFO+ subjects achieved a higher T _oesoph than PFO− subjects (P < 0.05). Subjects with a large PFO, but not those with a small PFO, had a higher T _oesoph than PFO− subjects (P < 0.05) during Trial 1 and increased T _oesoph breathing cold and dry air. These data suggest that the presence and size of a PFO are associated with T _oesoph in healthy humans but this is explained only partially by absence of respiratory system cooling of shunted blood.

Abbreviations

D_LCO: lung diffusion capacity for carbon monoxide
FEF_25–75: forced mid‐expiratory flow
FEV₁: forced expiratory volume in 1 s
FVC: forced vital capacity
HR: heart rate
PFO: patent foramen ovale
PFO+: subjects with a PFO
PFO−: subjects without a PFO
${\dot{Q}}_{C}$: cardiac output
RER: respiratory exchange ratio
RPE_{leg discomfort}: rate of perceived exertion for legs
RPE _dyspnoea: rate of perceived exertion for lungs
S_aO₂: arterial saturation of oxygen
S_pO₂: peripheral arterial oxygen saturation
T_air: ambient air temperature
T_core: core temperature
T_oesoph: oesophageal temperature
T_exp: expired air temperature
T_insp: inspired air temperature
TLC: total lung capacity
${\dot{V}}_{C O_{2}}$: carbon dioxide elimination
${\dot{V}}_{E}$: minute ventilation
${\dot{V}}_{E}$ / ${\dot{V}}_{O_{2}}$: ventilatory equivalent of oxygen
${\dot{V}}_{O_{2}}$: oxygen uptake
V_t: tidal volume

相似文献

What limits performance during whole‐body incremental exercise to exhaustion in humans?

David Morales‐Alamo José Losa‐Reyna Rafael Torres‐Peralta Marcos Martin‐Rincon Mario Perez‐Valera David Curtelin Jesús Gustavo Ponce‐González Alfredo Santana José A. L. Calbet 《The Journal of physiology》2015,593(20):4631-4648

Key points

At the end of an incremental exercise to exhaustion a large functional reserve remains in the muscles to generate power, even at levels far above the power output at which task failure occurs, regardless of the inspiratory O₂ pressure during the incremental exercise.
Exhaustion (task failure) is not due to lactate accumulation and the associated muscle acidification; neither the aerobic energy pathways nor the glycolysis are blocked at exhaustion.
Muscle lactate accumulation may actually facilitate early recovery after exhaustive exercise even under ischaemic conditions.
Although the maximal rate of ATP provision is markedly reduced at task failure, the resynthesis capacity remaining exceeds the rate of ATP consumption, indicating that task failure during an incremental exercise to exhaustion depends more on central than peripheral mechanisms.

Abstract

To determine the mechanisms causing task failure during incremental exercise to exhaustion (IE), sprint performance (10 s all‐out isokinetic) and muscle metabolites were measured before (control) and immediately after IE in normoxia (P_IO₂: 143 mmHg) and hypoxia (P_IO₂: 73 mmHg) in 22 men (22 ± 3 years). After IE, subjects recovered for either 10 or 60 s, with open circulation or bilateral leg occlusion (300 mmHg) in random order. This was followed by a 10 s sprint with open circulation. Post‐IE peak power output (W _peak) was higher than the power output reached at exhaustion during IE (P < 0.05). After 10 and 60 s recovery in normoxia, W _peak was reduced by 38 ± 9 and 22 ± 10% without occlusion, and 61 ± 8 and 47 ± 10% with occlusion (P < 0.05). Following 10 s occlusion, W _peak was 20% higher in hypoxia than normoxia (P < 0.05), despite similar muscle lactate accumulation ([La]) and phosphocreatine and ATP reduction. Sprint performance and anaerobic ATP resynthesis were greater after 60 s compared with 10 s occlusions, despite the higher [La] and [H⁺] after 60 s compared with 10 s occlusion recovery (P < 0.05). The mean rate of ATP turnover during the 60 s occlusion was 0.180 ± 0.133 mmol (kg wet wt)⁻¹ s⁻¹, i.e. equivalent to 32% of leg peak O₂ uptake (the energy expended by the ion pumps). A greater degree of recovery is achieved, however, without occlusion. In conclusion, during incremental exercise task failure is not due to metabolite accumulation or lack of energy resources. Anaerobic metabolism, despite the accumulation of lactate and H⁺, facilitates early recovery even in anoxia. This points to central mechanisms as the principal determinants of task failure both in normoxia and hypoxia, with lower peripheral contribution in hypoxia.

Abbreviations

Cr: creatine
d.w.: dry weight
F_IO₂: inspired oxygen fraction
HR: heart rate
HR_peak: peak heart rate
Hyp: hypoxia
IE: incremental exercise to exhaustion
La: lactate
Mb: myoglobin
Nx: normoxia
PCr: phosphocreatine
P_{ETC O₂}: end‐tidal CO₂ pressure
P_{ET O₂}: end‐tidal O₂ pressure
P_IO₂: partial pressure of inspired O₂
RER: respiratory exchange ratio
S_pO₂: haemoglobin oxygen saturation measured by pulse‐oximetry
TOI: tissue oxygenation index
${\dot{V}}_{C O_{2}}$: CO₂ production
${\dot{V}}_{C O_{2} peak}$: peak CO₂ production
${\dot{V}}_{E}$: minute ventilation
${\dot{V}}_{O_{2}}$: O₂ consumption
${\dot{V}}_{O_{2} \max}$: maximal O₂ uptake
${\dot{V}}_{O_{2} peak}$: peak O₂ uptake
WBIE: whole‐body incremental exercise
W_peak‐i: instantaneous peak power output
W_peak‐1: peak power output using 1 s averages
W_max: peak power output at exhaustion during the incremental exercise test
W_mean: mean power output during the 10 s sprints
w.w.: wet weight

相似文献

Intensity and physiological responses to the 6-minute walk test in middle-aged and older adults: a comparison with cardiopulmonary exercise testing

E.F. Sperandio R.L. Arantes A.C. Matheus R.P. Silva V.T. Lauria M. Romiti A.R.T. Gagliardi V.Z. Dourado 《Brazilian journal of medical and biological research》2015,48(4):349-353

The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake (

{\dot{V} O}_{2}

) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m², performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak

{\dot{V} O}_{2}

in the 6MWT corresponded to 78±13% of the peak

{\dot{V} O}_{2}

during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak

{\dot{V} O}_{2}

in CPET was adequately predicted by the 6MWD by a linear regression equation:

{\dot{V} O}_{2}

mL·min^-1·kg^-1 = -2.863 + (0.0563×6MWD_m) (R²=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged. 相似文献

Influence of exercise modality on agreement between gas exchange and heart rate variability thresholds

F.A. Cunha R.A. Montenegro A.W. Midgley F. Vasconcellos P.P. Soares P. Farinatti 《Brazilian journal of medical and biological research》2014,47(8):706-714

The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve (

% {\dot{V} O}_{2} R

) at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and

{\dot{V} O}_{2}

at GET and HRVT were 16 bpm (P<0.001) and 5.2 mL·kg^-1·min^-1 (P=0.001) higher in running than cycling, but no significant differences were observed between running and walking, or cycling and walking (P>0.05). There was a strong relationship between GET and HRVT, with R² ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and

{% \dot{V} O}_{2} R

was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and

{% \dot{V} O}_{2} R

at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise. 相似文献

Energy system contribution in a maximal incremental test: correlations with pacing and overall performance in a 10-km running trial

M.V. Damasceno L.A. Pasqua A.E. Lima-Silva R. Bertuzzi 《Brazilian journal of medical and biological research》2015,48(11):1048-1054

This study aimed to verify the association between the contribution of energy systems during an incremental exercise test (IET), pacing, and performance during a 10-km running time trial. Thirteen male recreational runners completed an incremental exercise test on a treadmill to determine the respiratory compensation point (RCP), maximal oxygen uptake (

{\dot{V} O}_{2 \max}

), peak treadmill speed (PTS), and energy systems contribution; and a 10-km running time trial (T10-km) to determine endurance performance. The fractions of the aerobic (W_AER) and glycolytic (W_GLYCOL) contributions were calculated for each stage based on the oxygen uptake and the oxygen energy equivalents derived by blood lactate accumulation, respectively. Total metabolic demand (W_TOTAL) was the sum of these two energy systems. Endurance performance during the T10-km was moderately correlated with RCP,

{\dot{V} O}_{2 \max}

and PTS (P<@0.05), and moderate-to-highly correlated with W_AER, W_GLYCOL, and W_TOTAL (P<0.05). In addition, W_AER, W_GLYCOL, and W_TOTAL were also significantly correlated with running speed in the middle (P<0.01) and final (P<0.01) sections of the T10-km. These findings suggest that the assessment of energy contribution during IET is potentially useful as an alternative variable in the evaluation of endurance runners, especially because of its relationship with specific parts of a long-distance race. 相似文献

Effects of prolonged expiration breathing on cardiopulmonary responses during incremental exercise

Takuya Matsumoto Takashi Masuda Kazuki Hotta Ryosuke Shimizu Akira Ishii Toshiki Kutsuna Kazuya Yamamoto Miyako Hara Naonobu Takahira Atsuhiko Matsunaga 《Respiratory physiology & neurobiology》2011,178(2):275-282

相似文献

10.

Differences in gas exchange between severities of chronic obstructive pulmonary disease

Wilawan Thirapatarapong Hilary F. Armstrong Byron M. Thomashow Matthew N. Bartels 《Respiratory physiology & neurobiology》2013,186(1):81-86

相似文献

11.

Short intermittent hypoxic exposures augment ventilation but do not alter regional cerebral and muscle oxygenation during hypoxic exercise

Debevec T Mekjavic IB 《Respiratory physiology & neurobiology》2012,181(2):132-142

相似文献

12.

Kinetics analysis of muscle arterial–venous O₂ difference profile during exercise

Priscila B. Barbosa Daniela M. Bravo J. Alberto Neder Leonardo F. Ferreira 《Respiratory physiology & neurobiology》2010,173(1):51-57

相似文献

13.

Variability of the ventilatory response to Duffin's modified hyperoxic and hypoxic rebreathing procedure in healthy awake humans

Dennis Jensen Graeme Mask Michael E. Tschakovsky 《Respiratory physiology & neurobiology》2010,170(2):185-197

相似文献

14.

Determinants of oxygen consumption during exercise on cycle ergometer: The effects of gravity acceleration

Julien Bonjour Carlo Capelli Guglielmo Antonutto Stefano Calza Enrico Tam Dag Linnarsson Guido Ferretti 《Respiratory physiology & neurobiology》2010,171(2):128-134

相似文献

15.

CO₂ relaxation of the rat lung parenchymal strip

Michael J. Emery Randy L. Eveland Jin-Hye Min Jacob Hildebrandt Erik R. Swenson 《Respiratory physiology & neurobiology》2013,186(1):33-39

相似文献

16.

Oxygen uptake kinetics at work onset: Role of cardiac output and of phosphocreatine breakdown

M.P. Francescato V. Cettolo P.E. di Prampero 《Respiratory physiology & neurobiology》2013,185(2):287-295

相似文献

17.

Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained

Miriam S. Nokia Sanna Lensu Juha P. Ahtiainen Petra P. Johansson Lauren G. Koch Steven L. Britton Heikki Kainulainen 《The Journal of physiology》2016,594(7):1855-1873

Key points

Aerobic exercise, such as running, enhances adult hippocampal neurogenesis (AHN) in rodents.
Little is known about the effects of high‐intensity interval training (HIT) or of purely anaerobic resistance training on AHN.
Here, compared with a sedentary lifestyle, we report a very modest effect of HIT and no effect of resistance training on AHN in adult male rats.
We found the most AHN in rats that were selectively bred for an innately high response to aerobic exercise that also run voluntarily and increase maximal running capacity.
Our results confirm that sustained aerobic exercise is key in improving AHN.

Abstract

Aerobic exercise, such as running, has positive effects on brain structure and function, such as adult hippocampal neurogenesis (AHN) and learning. Whether high‐intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training (RT) has similar effects on AHN is unclear. In addition, individual genetic variation in the overall response to physical exercise is likely to play a part in the effects of exercise on AHN but is less well studied. Recently, we developed polygenic rat models that gain differentially for running capacity in response to aerobic treadmill training. Here, we subjected these low‐response trainer (LRT) and high‐response trainer (HRT) adult male rats to various forms of physical exercise for 6–8 weeks and examined the effects on AHN. Compared with sedentary animals, the highest number of doublecortin‐positive hippocampal cells was observed in HRT rats that ran voluntarily on a running wheel, whereas HIT on the treadmill had a smaller, statistically non‐significant effect on AHN. Adult hippocampal neurogenesis was elevated in both LRT and HRT rats that underwent endurance training on a treadmill compared with those that performed RT by climbing a vertical ladder with weights, despite their significant gain in strength. Furthermore, RT had no effect on proliferation (Ki67), maturation (doublecortin) or survival (bromodeoxyuridine) of new adult‐born hippocampal neurons in adult male Sprague–Dawley rats. Our results suggest that physical exercise promotes AHN most effectively if the exercise is aerobic and sustained, especially when accompanied by a heightened genetic predisposition for response to physical exercise.

Abbreviations

AHN: adult hippocampal neurogenesis
BDNF: brain‐derived neurotrophic factor
BrdU: bromodeoxyuridine
HIT: high‐intensity interval training
HRT: high‐response trainer
LRT: low‐response trainer
RW: running wheel
Sed: sedentary
TBS: Tris‐buffered saline
${\dot{V}}_{O_{2} max}$: maximal oxygen uptake

相似文献

18.

Dynamic vs. fixed bag filling: Impact on cardiac output rebreathing protocol

Gerald S. Zavorsky Kenneth C. Beck Lauren M. Cass Raul Artal Peter D. Wagner 《Respiratory physiology & neurobiology》2010,171(1):22-30

相似文献

19.

Use of the Wasserman equation in optimization of the duration of the power ramp in a cardiopulmonary exercise test: a study of Brazilian men

D. C. Costa G. L. de Santi J. C. Crescêncio L. P. Seabra E. E. V. Carvalho V. Papa F. Marques L. Gallo Junior A. Schmidt 《Brazilian journal of medical and biological research》2015,48(12):1136-1144

This study aimed to analyze the agreement between measurements of unloaded oxygen uptake and peak oxygen uptake based on equations proposed by Wasserman and on real measurements directly obtained with the ergospirometry system. We performed an incremental cardiopulmonary exercise test (CPET), which was applied to two groups of sedentary male subjects: one apparently healthy group (HG, n=12) and the other had stable coronary artery disease (n=16). The mean age in the HG was 47±4 years and that in the coronary artery disease group (CG) was 57±8 years. Both groups performed CPET on a cycle ergometer with a ramp-type protocol at an intensity that was calculated according to the Wasserman equation. In the HG, there was no significant difference between measurements predicted by the formula and real measurements obtained in CPET in the unloaded condition. However, at peak effort, a significant difference was observed between oxygen uptake (

\dot{V}

O₂)_{peak(predicted)}and

\dot{V}

O_2peak(real)(nonparametric Wilcoxon test). In the CG, there was a significant difference of 116.26 mL/min between the predicted values by the formula and the real values obtained in the unloaded condition. A significant difference in peak effort was found, where

\dot{V}

O_2peak(real)was 40% lower than

\dot{V}

O_{2peak(predicted)}(nonparametric Wilcoxon test). There was no agreement between the real and predicted measurements as analyzed by Lin’s coefficient or the Bland and Altman model. The Wasserman formula does not appear to be appropriate for prediction of functional capacity of volunteers. Therefore, this formula cannot precisely predict the increase in power in incremental CPET on a cycle ergometer. 相似文献

20.

Dynamic pulmonary hyperinflation occurs without expiratory flow limitation in chronic heart failure during exercise

Stefania Chiari Chiara Torregiani Enrico Boni Sonia Bassini Enrico Vizzardi Claudio Tantucci 《Respiratory physiology & neurobiology》2013,189(1):34-41

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