scholarly journals Effect of cold air inhalation and isometric exercise on coronary blood flow and myocardial function in humans

2011 ◽  
Vol 111 (6) ◽  
pp. 1694-1702 ◽  
Author(s):  
Matthew D. Muller ◽  
Zhaohui Gao ◽  
Rachel C. Drew ◽  
Michael D. Herr ◽  
Urs A. Leuenberger ◽  
...  
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Maximal Voluntary Contraction ◽  
Myocardial Function ◽  
Isometric Exercise ◽  
Ambient Air ◽  
Voluntary Contraction ◽  
Isometric Handgrip ◽  
Transthoracic Doppler Echocardiography ◽  
Cold Air

The effects of cold air inhalation and isometric exercise on coronary blood flow are currently unknown, despite the fact that both cold air and acute exertion trigger angina in clinical populations. In this study, we used transthoracic Doppler echocardiography to measure coronary blood flow velocity (CBV; left anterior descending coronary artery) and myocardial function during cold air inhalation and handgrip exercise. Ten young healthy subjects underwent the following protocols: 5 min of inhaling cold air (cold air protocol), 5 min of inhaling thermoneutral air (sham protocol), 2 min of isometric handgrip at 30% of maximal voluntary contraction (grip protocol), and 5 min of isometric handgrip at 30% maximal voluntary contraction while breathing cold air (cold + grip protocol). Heart rate, blood pressure, inspired air temperature, CBV, myocardial function (tissue Doppler imaging), O2 saturation, and pulmonary function were measured. The rate-pressure product (RPP) was used as an index of myocardial O2 demand, whereas CBV was used as an index of myocardial O2 supply. Compared with the sham protocol, the cold air protocol caused a significantly higher RPP, but there was a significant reduction in CBV. The cold + grip protocol caused a significantly greater increase in RPP compared with the grip protocol ( P = 0.045), but the increase in CBV was significantly less ( P = 0.039). However, myocardial function was not impaired during the cold + grip protocol relative to the grip protocol alone. Collectively, these data indicate that there is a supply-demand mismatch in the coronary vascular bed when cold ambient air is breathed during acute exertion but myocardial function is preserved, suggesting an adequate redistribution of blood flow.

scholarly journals β-Adrenergic receptor blockade impairs coronary exercise hyperemia in young men but not older men

2014 ◽  
Vol 307 (10) ◽  
pp. H1497-H1503 ◽  
Author(s):  
Amanda J. Ross ◽  
Zhaohui Gao ◽  
Jonathan P. Pollock ◽  
Urs A. Leuenberger ◽  
Lawrence I. Sinoway ◽  
...  
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Adrenergic Receptor ◽  
Isometric Exercise ◽  
Young Men ◽  
Older Men ◽  
Handgrip Exercise ◽  
Isometric Handgrip ◽  
Transthoracic Doppler Echocardiography ◽  
Exercise Hyperemia

Patients with coronary artery disease have attenuated coronary vasodilator responses to physiological stress, which is partially attributed to a β-adrenergic receptor (β-AR)-mediated mechanisms. Whether β-ARs contribute to impaired coronary vasodilation seen with healthy aging is unknown. The purpose of this study was to investigate the role of β-ARs in coronary exercise hyperemia in healthy humans. Six young men (26 ± 1 yr) and seven older men (67 ± 4 yr) performed isometric handgrip exercise at 30% maximal voluntary contraction for 2 min after receiving intravenous propranolol, a β-AR antagonist, and no treatment. Isoproterenol, a β-AR agonist, was infused to confirm the β-AR blockade. Blood pressure and heart rate were monitored continuously, and coronary blood flow velocity (CBV, left anterior descending artery) was measured by transthoracic Doppler echocardiography. Older men had an attenuated ΔCBV to isometric exercise (3.8 ± 1.3 vs. 9.7 ± 2.1 cm/s, P = 0.02) compared with young men. Propranolol decreased the ΔCBV at peak handgrip exercise in young men (9.7 ± 2.1 vs. 2.7 ± 0.9 cm/s, P = 0.008). However, propranolol had no effect on ΔCBV in older men (3.8 ± 1.3 vs. 4.2 ± 1.9 cm/s, P = 0.9). Older men also had attenuated coronary hyperemia to low-dose isoproterenol. These data indicate that β-AR control of coronary blood flow is impaired in healthy older men.

scholarly journals Coronary responses to cold air inhalation following afferent and efferent blockade

2014 ◽  
Vol 307 (2) ◽  
pp. H228-H235 ◽  
Author(s):  
Matthew D. Muller ◽  
Zhaohui Gao ◽  
Patrick M. McQuillan ◽  
Urs A. Leuenberger ◽  
Lawrence I. Sinoway
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Coronary Blood Flow ◽  
Supply And Demand ◽  
Isometric Exercise ◽  
Peak Exercise ◽  
Rate Pressure Product ◽  
Isometric Handgrip ◽  
Cold Air ◽  
And Control

Cardiac ischemia and angina pectoris are commonly experienced during exertion in a cold environment. In the current study we tested the hypotheses that oropharyngeal afferent blockade (i.e., local anesthesia of the upper airway with lidocaine) as well as systemic β-adrenergic receptor blockade (i.e., intravenous propranolol) would improve the balance between myocardial oxygen supply and demand in response to the combined stimulus of cold air inhalation (−15 to −30°C) and isometric handgrip exercise (Cold + Grip). Young healthy subjects underwent Cold + Grip following lidocaine, propranolol, and control (no drug). Heart rate, blood pressure, and coronary blood flow velocity (CBV, from Doppler echocardiography) were continuously measured. Rate-pressure product (RPP) was calculated, and changes from baseline were compared between treatments. The change in RPP at the end of Cold + Grip was not different between lidocaine (2,441 ± 376) and control conditions (3,159 ± 626); CBV responses were also not different between treatments. With propranolol, heart rate (8 ± 1 vs. 14 ± 3 beats/min) and RPP responses to Cold + Grip were significantly attenuated. However, at peak exercise propranolol also resulted in a smaller ΔCBV (1.4 ± 0.8 vs. 5.3 ± 1.4 cm/s, P = 0.035), such that the relationship between coronary flow and cardiac metabolism was impaired under propranolol (0.43 ± 0.37 vs. 2.1 ± 0.63 arbitrary units). These data suggest that cold air breathing and isometric exercise significantly influence efferent control of coronary blood flow. Additionally, β-adrenergic vasodilation may play a significant role in coronary regulation during exercise.

Sex differences in forebrain and cardiovagal responses at the onset of isometric handgrip exercise: a retrospective fMRI study

2007 ◽  
Vol 103 (4) ◽  
pp. 1402-1411 ◽  
Author(s):  
Savio W. Wong ◽  
Derek S. Kimmerly ◽  
Nicholas Massé ◽  
Ravi S. Menon ◽  
David F. Cechetto ◽  
...  
Keyword(s):  
Sex Differences ◽  
Maximal Voluntary Contraction ◽  
Cardiovascular Response ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Anterior Cingulate ◽  
Exercise Heart Rate ◽  
Handgrip Exercise ◽  
Isometric Handgrip ◽  
Ventral Medial Prefrontal Cortex

In general, cardiac regulation is dominated by the sympathetic and parasympathetic nervous systems in men and women, respectively. Our recent study had revealed sex differences in the forebrain network associated with sympathoexcitatory response to baroreceptor unloading. The present study further examined the sex differences in forebrain modulation of cardiovagal response at the onset of isometric exercise. Forebrain activity in healthy men ( n = 8) and women ( n = 9) was measured using functional magnetic resonance imaging during 5 and 35% maximal voluntary contraction handgrip exercise. Heart rate (HR), mean arterial pressure (MAP), and muscle sympathetic nerve activity (MSNA) were collected in a separate recording session. During the exercise, HR and MAP increased progressively, while MSNA was suppressed ( P < 0.05). Relative to men, women demonstrated smaller HR (8 ± 2 vs. 18 ± 3 beats/min) and MAP (3 ± 2 vs. 11 ± 2 mmHg) responses to the 35% maximal voluntary contraction trials ( P < 0.05). Although a similar forebrain network was activated in both groups, the smaller cardiovascular response in women was reflected in a weaker insular cortex activation. Nevertheless, men did not show a stronger deactivation at the ventral medial prefrontal cortex, which has been associated with modulating cardiovagal activity. In contrast, the smaller cardiovascular response in women related to their stronger suppression of the dorsal anterior cingulate cortex activity, which has been associated with sympathetic control of the heart. Our findings revealed sex differences in both the physiological and forebrain responses to isometric exercise.

scholarly journals Cold air breathing during isometric handgrip: effect of healthy aging on coronary blood flow

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Matthew David Muller ◽  
Zhaohui Gao ◽  
Jessica Mast ◽  
Cheryl Blaha ◽  
Rachel C Drew ◽  
...  
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Healthy Aging ◽  
Isometric Handgrip ◽  
Air Breathing ◽  
Cold Air

scholarly journals Aging attenuates the coronary blood flow response to cold air breathing and isometric handgrip in healthy humans

2012 ◽  
Vol 302 (8) ◽  
pp. H1737-H1746 ◽  
Author(s):  
Matthew D. Muller ◽  
Zhaohui Gao ◽  
Jessica L. Mast ◽  
Cheryl A. Blaha ◽  
Rachel C. Drew ◽  
...  
Keyword(s):  
Older Adults ◽  
Blood Flow ◽  
Coronary Blood Flow ◽  
Maximum Voluntary Contraction ◽  
Cold Pressor Test ◽  
Left Ventricular ◽  
Doppler Imaging ◽  
Isometric Handgrip ◽  
Cold Air ◽  
Older Subjects

The purpose of this echocardiography study was to measure peak coronary blood flow velocity (CBVpeak) and left ventricular function (via tissue Doppler imaging) during separate and combined bouts of cold air inhalation (−14 ± 3°C) and isometric handgrip (30% maximum voluntary contraction). Thirteen young adults and thirteen older adults volunteered to participate in this study and underwent echocardiographic examination in the left lateral position. Cold air inhalation was 5 min in duration, and isometric handgrip (grip protocol) was 2 min in duration; a combined stimulus (cold + grip protocol) and a cold pressor test (hand in 1°C water) were also performed. Heart rate, blood pressure, O2 saturation, and inspired air temperature were monitored on a beat-by-beat basis. The rate-pressure product (RPP) was used as an index of myocardial O2 demand, and CBVpeak was used as an index of myocardial O2 supply. The RPP response to the grip protocol was significantly blunted in older subjects (Δ1,964 ± 396 beats·min−1·mmHg) compared with young subjects (Δ3,898 ± 452 beats·min−1·mmHg), and the change in CBVpeak was also blunted (Δ6.3 ± 1.2 vs. 11.2 ± 2.0 cm/s). Paired t-tests showed that older subjects had a greater change in the RPP during the cold + grip protocol [Δ2,697 ± 391 beats·min−1·mmHg compared with the grip protocol alone (Δ2,115 ± 375 beats·min−1·mmHg)]. An accentuated RPP response to the cold + grip protocol (compared with the grip protocol alone) without a concomitant increase in CBVpeak may suggest a dissociation between the O2 supply and demand in the coronary circulation. In conclusion, older adults have blunted coronary blood flow responses to isometric exercise.

Cutaneous vascular and sudomotor responses to isometric exercise in humans

1995 ◽  
Vol 79 (6) ◽  
pp. 1946-1950 ◽  
Author(s):  
C. G. Crandall ◽  
J. Musick ◽  
J. P. Hatch ◽  
D. L. Kellogg ◽  
J. M. Johnson
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Sweat Rate ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Isometric Handgrip ◽  
Noninvasive Blood Pressure ◽  
Doppler Flowmetry ◽  
Vasodilator Activity ◽  
Sudomotor Activity

To identify whether isometric handgrip exercise (IHG) affects cutaneous vasoconstrictor and/or active vasodilator activities, seven subjects (6 men and 1 woman) performed 30% maximal voluntary contraction of a forearm under normothermic (1 bout) and hyperthermic (2 bouts) conditions. Skin blood flow was indexed by laser-Doppler flowmetry at a contralateral forearm site at which adrenergic vasoconstrictor function was blocked by iontophoresis of bretylium tosylate (BT) and therefore only has active vasodilation as a mechanism for reflex control. Skin blood flow was also monitored at an adjacent untreated site. Cutaneous vascular conductance (CVC) was calculated from the flow signal and noninvasive blood pressure. CVC was normalized to the value obtained from maximal vasodilation at that site. Sweat rate (SR) was measured at the same locations. During normothermia, IHG did not affect CVC at the control or BT-treated sites, nor did IHG affect SR (P > 0.05). The second bout of IHG in hyperthermia evoked significant reductions in CVC at the untreated (69.4 +/- 3.4 to 58.9 +/- 2.5% of maximum, P < 0.05) and BT-treated sites (75.4 +/- 6.1 to 64.4 +/- 6.2% of maximum, P < 0.05), whereas SR significantly increased (0.62 +/- 0.16 to 0.70 +/- 0.17 mg.cm-2.min-1, P < 0.05). These findings uniquely show that, in hyperthermia, IHG reduces active vasodilator activity while at the same time sudomotor activity is increasing. This suggests independent control of these effectors.

Forearm endurance training attenuates sympathetic nerve response to isometric handgrip in normal humans

1992 ◽  
Vol 72 (3) ◽  
pp. 1039-1043 ◽  
Author(s):  
V. K. Somers ◽  
K. C. Leo ◽  
R. Shields ◽  
M. Clary ◽  
A. L. Mark
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Endurance Training ◽  
Sympathetic Nerve ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Isometric Handgrip ◽  
Nerve Response ◽  
The Right ◽  
Muscle Chemoreflex

Recent evidence indicates that muscle ischemia and activation of the muscle chemoreflex are the principal stimuli to sympathetic nerve activity (SNA) during isometric exercise. We postulated that physical training would decrease muscle chemoreflex stimulation during isometric exercise and thereby attenuate the SNA response to exercise. We investigated the effects of 6 wk of unilateral handgrip endurance training on the responses to isometric handgrip (IHG: 33% of maximal voluntary contraction maintained for 2 min). In eight normal subjects the right arm underwent exercise training and the left arm sham training. We measured muscle SNA (peroneal nerve), heart rate, and blood pressure during IHG before vs. after endurance training (right arm) and sham training (left arm). Maximum work to fatigue (an index of training efficacy) was increased by 1,146% in the endurance-trained arm and by only 40% in the sham-trained arm. During isometric exercise of the right arm, SNA increased by 111 +/- 27% (SE) before training and by only 38 +/- 9% after training (P less than 0.05). Endurance training did not significantly affect the heart rate and blood pressure responses to IHG. We also measured the SNA response to 2 min of forearm ischemia after IHG in five subjects. Endurance training also attenuated the SNA response to postexercise forearm ischemia (P = 0.057). Sham training did not significantly affect the SNA responses to IHG or forearm ischemia. We conclude that endurance training decreases muscle chemoreflex stimulation during isometric exercise and thereby attenuates the sympathetic nerve response to IHG.

Increased cardiovascular response to static contraction of larger muscle groups

1983 ◽  
Vol 54 (2) ◽  
pp. 434-437 ◽  
Author(s):  
D. R. Seals ◽  
R. A. Washburn ◽  
P. G. Hanson ◽  
P. L. Painter ◽  
F. J. Nagle
Keyword(s):  
Muscle Mass ◽  
Maximal Voluntary Contraction ◽  
Cardiovascular Response ◽  
Isometric Exercise ◽  
Voluntary Contraction ◽  
Active Muscle ◽  
Leg Extension ◽  
Arterial Blood ◽  
Static Contraction ◽  
Muscle Groups

The purpose of this study was to investigate the influence of the size of the active muscle mass on the cardiovascular response to static contraction. Twelve male subjects performed one-arm handgrip (HG), two-leg extension (LE), and a “dead-lift” maneuver (DL) in a randomly assigned order for 3 min at 30% of maximal voluntary contraction. O2 uptake (VO2), heart rate (HR), and mean intra-arterial blood pressure (MABP) were measured at rest and, in addition to absolute tension exerted, throughout contraction. There was a direct relationship between the size of the active muscle mass and the magnitude of the increases in VO2, HR, and MABP, even though all contractions were performed at the same relative intensity. Tension, VO2, HR, and MABP increased progressively from HG to LE to DL. It was concluded that at the same percentage of maximal voluntary contraction, the magnitude of the cardiovascular response to isometric exercise is directly influenced by the size of the contracting muscle mass.

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