Heart rate kinetics during exercise in patients with subclinical hypothyroidism

Studies suggest that patients with subclinical hypothyroidism (SH) have sympathovagal imbalance, which could lead to a slower heart rate (HR) response in the transition from rest to exercise. Thus the objective of this study was to investigate the behavior of the HR kinetics in patients with SH during the transition from rest to exercise. The study included 18 SH women [thyroid stimulating hormone (TSH) = 6.95 ± 2.94 μIU/ml and free thyroxine (FT4) = 0.96 ± 0.15 ng/dl] and 17 euthyroid women (TSH = 2.28 ± 0.84 μIU/ml and FT4 = 0.98 ± 0.07 ng/dl). Both groups were matched for physical activity, menopausal status, and age. The HR kinetics was obtained during the course of a constant-load exercise (50 W), for 6 min, in a cycle ergometer, and quantified from the mean response time (MRT), which is equivalent to the time taken to reach 63% of the HR at steady state. SH patients showed slower HR kinetics than the control group (MRT = 48.5 ± 17.6 vs. 36.0 ± 10.3 s, P = 0.015). The MRT has been shown to correlate with the level of physical activity ( r = −0.361; P = 0.033) and with the subjective perception of exertion at the end of the exercise ( r = 0.365; P = 0.031). It is concluded that SH patients have slower HR kinetics in the transition from rest to exercise compared with euthyroid women, with this impairment being associated with lower levels of physical activity. NEW & NOTEWORTHY Subclinical hypothyroidism patients have slower heart rate kinetics in the transition from rest to exercise when performing a constant-load exercise at 50 W.

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Abnormal oxygen uptake kinetic responses in women with type II diabetes mellitus

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.1.310 ◽

1998 ◽

Vol 85 (1) ◽

pp. 310-317 ◽

Cited By ~ 150

Author(s):

Judith G. Regensteiner ◽

Timothy A. Bauer ◽

Jane E. B. Reusch ◽

Suzanne L. Brandenburg ◽

Jeffrey M. Sippel ◽

...

Keyword(s):

Diabetes Mellitus ◽

Heart Rate ◽

Oxygen Consumption ◽

Type Ii Diabetes ◽

Lactate Threshold ◽

Type Ii Diabetes Mellitus ◽

Constant Load ◽

Type Ii ◽

Rate Kinetics ◽

Heart Rate Kinetics

Persons with type II diabetes mellitus (DM), even without cardiovascular complications have a decreased maximal oxygen consumption (V˙o2 max) and submaximal oxygen consumption (V˙o2) during graded exercise compared with healthy controls. We evaluated the hypothesis that change in the rate ofV˙o2in response to the onset of constant-load exercise (measured byV˙o2-uptake kinetics) was slowed in persons with type II DM. Ten premenopausal women with uncomplicated type II DM, 10 overweight, nondiabetic women, and 10 lean, nondiabetic women had aV˙o2 maxtest. On two separate occasions, subjects performed 7-min bouts of constant-load bicycle exercise at workloads below and above the lactate threshold to enable measurements of V˙o2kinetics and heart rate kinetics (measuring rate of heart rate rise).V˙o2 maxwas reduced in subjects with type II DM compared with both lean and overweight controls ( P < 0.05). Subjects with type II DM had slowerV˙o2and heart rate kinetics than did controls at constant workloads below the lactate threshold. The data suggest a notable abnormality in the cardiopulmonary response at the onset of exercise in people with type II DM. The findings may reflect impaired cardiac responses to exercise, although an additional defect in skeletal muscle oxygen diffusion or mitochondrial oxygen utilization is also possible.

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Oxygen uptake and heart rate kinetics during heavy exercise: a comparison between arm cranking and leg cycling

European Journal of Applied Physiology ◽

10.1007/s00421-002-0690-5 ◽

2002 ◽

Vol 88 (1-2) ◽

pp. 100-106 ◽

Cited By ~ 32

Author(s):

Donald Schneider ◽

Andrew Wing ◽

Norman Morris

Keyword(s):

Heart Rate ◽

Oxygen Uptake ◽

Heavy Exercise ◽

Arm Cranking ◽

Leg Cycling ◽

Rate Kinetics ◽

Heart Rate Kinetics

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V˙o 2 and heart rate kinetics in cycling: transitions from an elevated baseline

Journal of Applied Physiology ◽

10.1152/jappl.2001.90.6.2081 ◽

2001 ◽

Vol 90 (6) ◽

pp. 2081-2087 ◽

Cited By ~ 55

Author(s):

S. E. Bearden ◽

R. J. Moffatt

Keyword(s):

Heart Rate ◽

Base Excess ◽

Slow Component ◽

Lactate Concentration ◽

Fast Component ◽

Square Wave ◽

Mean Response Time ◽

Rate Kinetics ◽

Component Amplitude ◽

Heart Rate Kinetics

The purpose of this study was to examine oxygen consumption (V˙o 2) and heart rate kinetics during moderate and repeated bouts of heavy square-wave cycling from an exercising baseline. Eight healthy, male volunteers performed square-wave bouts of leg ergometry above and below the gas exchange threshold separated by recovery cycling at 35%V˙o 2 peak.V˙o 2 and heart rate kinetics were modeled, after removal of phase I data by use of a biphasic on-kinetics and monoexponential off-kinetics model. Fingertip capillary blood was sampled 45 s before each transition for base excess, HCO[Formula: see text] and lactate concentration, and pH. Base excess and HCO[Formula: see text] concentration were significantly lower, whereas lactate concentration and pH were not different before the second bout. The results confirm earlier reports of a smaller mean response time in the second heavy bout. This was the result of a significantly greater fast-component amplitude and smaller slow-component amplitude with invariant fast-component time constant. A role for local oxygen delivery limitation in heavy exercise transitions with unloaded but not moderate baselines is presented.

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Heart rate recovery after constant-load exercise tests is decreased in proportion to the importance (severity and diffusion) of exercise-induced lower-limb ischaemia

Clinical Physiology and Functional Imaging ◽

10.1111/j.1475-097x.2010.00978.x ◽

2010 ◽

Vol 31 (1) ◽

pp. 48-53 ◽

Cited By ~ 4

Author(s):

Guillaume Mahé ◽

Maya Zeenny ◽

Nafi Ouedraogo ◽

Bruno Vielle ◽

Georges Leftheriotis ◽

...

Keyword(s):

Heart Rate ◽

Lower Limb ◽

Heart Rate Recovery ◽

Constant Load ◽

Limb Ischaemia ◽

Exercise Tests ◽

Lower Limb Ischaemia ◽

Exercise Induced ◽

And Diffusion ◽

Constant Load Exercise

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Greater Exercise Pressor Response Is Associated With Impaired Claudication Outcomes in Symptomatic Peripheral Artery Disease

Angiology ◽

10.1177/0003319718790876 ◽

2018 ◽

Vol 70 (3) ◽

pp. 220-228 ◽

Cited By ~ 4

Author(s):

Andrew W. Gardner ◽

Polly S. Montgomery ◽

Ming Wang ◽

Chixiang Chen ◽

Marcos Kuroki ◽

...

Keyword(s):

Heart Rate ◽

Peripheral Artery Disease ◽

Pressor Response ◽

Constant Load ◽

Rate Pressure Product ◽

Treadmill Test ◽

Peripheral Artery ◽

Negatively Associated ◽

Artery Disease ◽

Constant Load Exercise

We determined whether a greater exercise pressor response during a constant-load treadmill test was associated with lower peak walking time (PWT) and claudication onset time (COT) measured during a graded maximal treadmill test in 304 patients with symptomatic peripheral artery disease (PAD). The exercise pressor response was assessed by measuring heart rate and blood pressure (BP) at rest and during a constant-load treadmill test (speed = 2 mph, grade = 0%). After only 2 minutes of walking, mean heart rate increased by 26 beats/min from rest and mean systolic BP increased by 16 mm Hg. In adjusted analyses, increases in systolic BP ( P = .021), heart rate ( P = .002), mean arterial pressure ( P = .034), and rate–pressure product ( P < .001) from rest to 2 minutes of constant-load exercise were negatively associated with COT. Similarly, increases in heart rate ( P = .012) and rate–pressure product ( P = .018) from rest to 2 minutes of constant-load exercise were negatively associated with PWT. A greater exercise pressor response observed after only 2 minutes of walking at no incline was independently associated with impaired claudication outcomes in patients with symptomatic PAD. The implication is that the exercise pressor response is an important and easily obtained clinical measurement that partially explains differences in PWT and COT.

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Effects of surgical face masks on cardiopulmonary parameters during steady state exercise

Scientific Reports ◽

10.1038/s41598-020-78643-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

J. Lässing ◽

R. Falz ◽

C. Pökel ◽

S. Fikenzer ◽

U. Laufs ◽

...

Keyword(s):

Heart Rate ◽

Steady State ◽

Airway Resistance ◽

Perceived Exertion ◽

Endurance Performance ◽

Constant Load ◽

Rating Of Perceived Exertion ◽

Lactate Minimum ◽

Load Tests ◽

Constant Load Exercise

AbstractWearing face masks reduce the maximum physical performance. Sports and occupational activities are often associated with submaximal constant intensities. This prospective crossover study examined the effects of medical face masks during constant-load exercise. Fourteen healthy men (age 25.7 ± 3.5 years; height 183.8 ± 8.4 cm; weight 83.6 ± 8.4 kg) performed a lactate minimum test and a body plethysmography with and without masks. They were randomly assigned to two constant load tests at maximal lactate steady state with and without masks. The cardiopulmonary and metabolic responses were monitored using impedance cardiography and ergo-spirometry. The airway resistance was two-fold higher with the surgical mask (SM) than without the mask (SM 0.58 ± 0.16 kPa l−1 vs. control [Co] 0.32 ± 0.08 kPa l−1; p < 0.01). The constant load tests with masks compared with those without masks resulted in a significantly different ventilation (77.1 ± 9.3 l min−1 vs. 82.4 ± 10.7 l min−1; p < 0.01), oxygen uptake (33.1 ± 5 ml min−1 kg−1 vs. 34.5 ± 6 ml min−1 kg−1; p = 0.04), and heart rate (160.1 ± 11.2 bpm vs. 154.5 ± 11.4 bpm; p < 0.01). The mean cardiac output tended to be higher with a mask (28.6 ± 3.9 l min−1 vs. 25.9 ± 4.0 l min−1; p = 0.06). Similar blood pressure (177.2 ± 17.6 mmHg vs. 172.3 ± 15.8 mmHg; p = 0.33), delta lactate (4.7 ± 1.5 mmol l−1 vs. 4.3 ± 1.5 mmol l−1; p = 0.15), and rating of perceived exertion (6.9 ± 1.1 vs. 6.6 ± 1.1; p = 0.16) were observed with and without masks. Surgical face masks increase airway resistance and heart rate during steady state exercise in healthy volunteers. The perceived exertion and endurance performance were unchanged. These results may improve the assessment of wearing face masks during work and physical training.

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