84 Effects of incremental conditioning and supplemental dietary tryptophan on pre, mid, and post-exercise heart rate and respiratory rate in sled dogs

Abstract Repetitive bouts of resistance and aerobic exercise can have dramatic effects on whole body physiology. Dietary tryptophan supplementation supports protein turnover and serotonin production, which assist in responses to exercise. The objective of this study was to investigate the effects of a 12-week incremental exercise regimen and supplemental dietary tryptophan on pre-, mid-, and post-exercise heart rate and respiratory rate in sled dogs. Sixteen dogs (mean age of 4.8 ± 2.5 years, body weight 24.3 ± 4.3 kg) were blocked for sex, age, and body weight, and randomly allocated to a control diet or the control plus tryptophan diet (tryptophan to large-neutral-amino-acid ratio of 0.075:1). All dogs participated in a 12-week conditioning regimen with controlled exercise challenges at week -1 and subsequently every 3 weeks. Electrocardiogram electrodes and thoracic rib bands were worn to record heart rate and respiratory rate (EMKA Tech., Falls Church, VA, USA) prior to, during, and following each exercise challenge. A trans regression, mixed, and correlation model were used where appropriate to assess the fixed effects of treatment and week, and explore linear relationships between recovery time and week in SAS (v 9.4). No differences were found in heart rate between treatment groups for any training level (P > 0.10). Working, recovery, and time required for heart rate to recover post-exercise decreased from week -1 to week 11 (P < 0.05). Correlation analysis indicated that treatment dogs recovered respiratory rate faster post-exercise compared to control (r = -0.421, P < 0.05). Resting, recovery and time required for respiratory rate to recover post-exercise decreased from baseline to week 11 (P < 0.05). This data suggests improvement in cardiorespiratory fitness was observed over 12 weeks of training and that tryptophan may support respiratory function during exercise recovery.

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Exercise but Not Supplemental Dietary Tryptophan Influences Heart Rate and Respiratory Rate in Sled Dogs

Veterinary Sciences ◽

10.3390/vetsci7030097 ◽

2020 ◽

Vol 7 (3) ◽

pp. 97 ◽

Cited By ~ 1

Author(s):

Emma Thornton ◽

James R. Templeman ◽

Michael Bower ◽

John P. Cant ◽

Graham P. Holloway ◽

...

Keyword(s):

Heart Rate ◽

Amino Acid ◽

Respiratory Rate ◽

Control Diet ◽

Neutral Amino Acid ◽

Large Neutral Amino Acid ◽

Post Exercise ◽

Sled Dogs ◽

Exercise Regimen ◽

Acid Ratio

Tryptophan (Trp), an indispensable amino acid for dogs, is the precursor of serotonin, a neurotransmitter with a variety of effects throughout the body, including the ability to modulate cardiac and pulmonary activity. This study aimed to investigate the effects of a 12-week incremental exercise regimen and supplemental dietary Trp on heart rate (HR) and respiratory rate (RR) in client-owned sled dogs. Sixteen Siberian huskies were randomly allocated to either treatment or control diet groups. Both groups were fed a control diet (Trp to large neutral amino acid ratio of 0.047:1); however, treatment dogs received a Trp supplement to achieve a Trp to large neutral amino acid ratio of 0.075:1. Every three weeks, external telemetry equipment was used to non-invasively measure and record HR and RR at a resting, working, and post-exercise state in a controlled exercise challenge. A mixed model was used to test differences between diet, activity parameter, and week. Dietary Trp supplementation had no effect on HR or RR. Independent of diet, resting, working, post-exercise HR, and time to recover post-exercise HR decreased from week −1 to week 11 (p < 0.05). Resting HR had the greatest reduction from week −1 to week 11 (21%, p < 0.05). Working RR did not change with exercise (p > 0.10), but rRR and postRR decreased from week −1 to week 11 (p < 0.05). These data suggest that the exercise regimen the dogs were subjected to may have positively impacted the dogs’ capacity to sustain aerobic exercise, whereas Trp supplementation had no effect on HR or RR.

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Central Command and the Regulation of Exercise Heart Rate Response in Heart Failure with Preserved Ejection Fraction

Circulation ◽

10.1161/circulationaha.120.048338 ◽

2020 ◽

Author(s):

Satyam Sarma ◽

Erin Howden ◽

Justin Lawley ◽

Mitchel Samels ◽

Benjamin D. Levine

Keyword(s):

Heart Rate ◽

Circulatory Arrest ◽

Cardiopulmonary Exercise Testing ◽

Voluntary Contraction ◽

Whole Body ◽

Exercise Heart Rate ◽

Central Command ◽

Post Exercise ◽

Arterial Blood ◽

Autonomic Pathways

Background: Chronotropic incompetence (CI) is common in HFpEF and is linked to impaired aerobic capacity. Whether upstream autonomic signaling pathways responsible for raising exercise heart rate (HR) are impaired in HFpEF is unknown. We investigated the integrity of central command and muscle metaboreceptor function, two predominant mechanisms responsible for exertional increases in HR, in HFpEF and senior control subjects. Methods: Fourteen healthy, senior controls (7M,7F) and 20 carefully screened HFpEF patients (8M,12F) underwent cardiopulmonary exercise testing (peak VO 2 ) and static handgrip exercise at 40% of maximal voluntary contraction (MVC) to fatigue with post-exercise circulatory arrest (PECA) for 2 minutes to assess central command and metaboreceptor function respectively. Results: Peak VO 2 (13.1 ± 3.4 vs 22.7 ± 4.0 ml/kg/min; p<0.001) and HR (122 ± 20 vs 155 ± 14 bpm; p<0.001) were lower in HFpEF than senior controls. There were no significant differences in peak HR response during static handgrip between groups (HFpEF vs controls: 90 ± 13 vs 93 ± 10 bpm; p=0.49). Metaboreceptor function defined as mean arterial blood pressure at the end of PECA was also not significantly different between groups. Conclusions: Central command (vagally mediated) and metaboreceptor function (sympathetically mediated) in patients with HFpEF were not different from healthy senior controls despite significantly lower peak whole-body exercise heart rates. These results demonstrate key reflex autonomic pathways regulating exercise heart rate responsiveness are intact in HFpEF.

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Effects of an Acute Bout of Exercise on Salivary Lactoferrin Responses among Smokers and Non-Smokers

Journal of Science and Technology ◽

10.30880/jst.2021.13.01.002 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Halimatun Saadiah Ahmad ◽

◽

Ayu Suzailiana Muhamad ◽

Keyword(s):

Heart Rate ◽

Body Weight ◽

Perceived Exertion ◽

Exercise Session ◽

Exercise Heart Rate ◽

Negative Effects ◽

Post Exercise ◽

Acute Bout ◽

Saliva Flow ◽

Study Participants

Smoking can weaken immune function as reported in previous studies. However, benefits of exercise in reducing negative effects of smoking on salivary lactoferrin responses is scarce to date. Hence, the purpose of this study is to determine the effects of an acute bout of exercise on salivary lactoferrin responses among smokers and non-smokers. Eighteen sedentary men were recruited; nine smokers (age = 22.4 ± 1.4 years; BMI = 22.1 ± 1.1 kg/m2) and nine non-smokers (age = 22.1 ± 0.7 years old; BMI = 22.5 ± 1.9 kg/m2). In this study, participants cycled at an intensity of 60% maximum heart rate for 60 minutes. Participants were given cool water as much as 3 ml/kg body weight at minutes 20 and 40 during the exercise session. Participants’ body weight and saliva samples were collected at pre and post-exercise. Heart rate and rate of perceived exertion (RPE) were recorded at pre, during and post-exercise. Mixed ANOVA was used to measure significant differences between groups and within group. The results showed that saliva flow rate, lactoferrin concentration and lactoferrin secretion rate were not significantly different (p>0.05) between smokers and non-smokers groups and also between pre and post-exercise within each group. Heart rate and RPE showed significant increased (p<0.05) during the exercise session in both groups. As a conclusion, acute bout of exercised does not affect salivary lactoferrin responses among sedentary smokers and non-smokers men.

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Parasympathetic Reinnervation Accompanied By Improved Post-Exercise Heart Rate Recovery and Quality of Life in Heart Transplant Recipients

The Journal of Heart and Lung Transplantation ◽

10.1016/j.healun.2015.01.847 ◽

2015 ◽

Vol 34 (4) ◽

pp. S301

Author(s):

T. Imamura ◽

K. Kinugawa ◽

T. Inaba ◽

H. Maki ◽

M. Hatano ◽

...

Keyword(s):

Quality Of Life ◽

Heart Rate ◽

Heart Transplant ◽

Heart Rate Recovery ◽

Exercise Heart Rate ◽

Transplant Recipients ◽

Post Exercise ◽

Heart Transplant Recipients

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Post-exercise heart rate recovery in individuals with spinal cord injury

Spinal Cord ◽

10.1038/sc.2009.196 ◽

2010 ◽

Vol 48 (8) ◽

pp. 639-644 ◽

Cited By ~ 8

Author(s):

J N Myers ◽

L Hsu ◽

D Hadley ◽

M Y Lee ◽

B J Kiratli

Keyword(s):

Spinal Cord ◽

Heart Rate ◽

Spinal Cord Injury ◽

Heart Rate Recovery ◽

Exercise Heart Rate ◽

Post Exercise ◽

Cord Injury

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Developmental pattern of hypercapnic and hypoxic ventilatory responses from childhood to adulthood

Journal of Applied Physiology ◽

10.1152/jappl.1994.76.1.314 ◽

1994 ◽

Vol 76 (1) ◽

pp. 314-320 ◽

Cited By ~ 59

Author(s):

C. L. Marcus ◽

W. B. Glomb ◽

D. J. Basinski ◽

S. L. Davidson ◽

T. G. Keens

Keyword(s):

Heart Rate ◽

Body Weight ◽

Body Size ◽

Respiratory Rate ◽

Body Surface ◽

Vital Capacity ◽

Developmental Pattern ◽

Ventilatory Responses ◽

End Tidal ◽

Arterial O2 Saturation

The developmental pattern of ventilatory responses, through childhood and puberty into adulthood, is not known. Therefore we studied hypercapnic (HCVR) and hypoxic ventilatory responses (HOVR) in 59 subjects (29 males and 30 females) 4–49 yr of age, of whom 35 were children ( < 18 yr old). There was a significant correlation between HCVR and weight (r = 0.33, P < 0.02), vital capacity (r = 0.30, P < 0.05), and body surface area (r = 0.30, P < 0.05) but not height (r = 0.22, NS). There was no correlation between HOVR and any of the correcting factors. To account for disparities in body size, volume-related results were scaled for body weight. The HCVR corrected for weight (HCVR/WT) decreased with age (r = -0.57, P < 0.001). HCVR/WT was significantly higher in children than in adults (0.056 +/- 0.024 vs. 0.032 +/- 0.015 l.kg-1 x min-1. Torr end-tidal PCO2-1, P < 0.001). The (tidal volume/inspiratory duration)/weight, respiratory rate, and heart rate responses to hypercapnia were increased in the children, and the CO2 threshold was lower (36 +/- 5 vs. 40 +/- 6 Torr, P < 0.05). Similarly, the HOVR corrected for weight (HOVR/WT) decreased with age (r = 0.34, P < 0.05), and HOVR/WT was significantly higher in children than in adults (-0.035 +/- 0.017 vs. -0.024 +/- 0.016 l.kg-1 x min-1.% arterial O2 saturation-1, P < 0.02). The respiratory rate and heart rate responses to hypoxia were increased in the children. We conclude that rebreathing HCVR and HOVR are higher during childhood than during adulthood.

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Supplemental Fiber Affects Body Temperature and Fecal Metabolites but Not Respiratory Rate or Body Composition in Mid-Distance Training Sled Dogs

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.639335 ◽

2021 ◽

Vol 8 ◽

Author(s):

Emma Thornton ◽

Eve Robinson ◽

James R. Templeman ◽

Lindy Bruggink ◽

Michael Bower ◽

...

Keyword(s):

Body Composition ◽

Body Temperature ◽

Respiratory Rate ◽

Dry Matter ◽

Gut Health ◽

Soluble Fiber ◽

Post Exercise ◽

Distance Training ◽

Sled Dogs ◽

Matter Basis

Dietary fiber affects canine physiology in many ways, such as increasing colonic absorption of water and improving gut health, both of which may positively impact exercise performance. The objectives of this study were to investigate the effects of increased dietary soluble fiber and incremental training on respiratory rate (RR), internal body temperature (BT), body composition, and fecal metabolites in mid-distance training sled dogs. Fourteen dogs (12 Siberian and 2 Alaskan Huskies) were blocked by age, sex, and body weight (BW) and then randomly allocated into one of two diet groups. Seven dogs were fed a dry extruded control diet (Ctl) with an insoluble:soluble fiber ratio of 4:1 (0.74% soluble fiber on a dry-matter basis), and seven dogs were fed a dry extruded treatment diet (Trt) with an insoluble:soluble fiber ratio of 3:1 (2.12% soluble fiber on a dry-matter basis). Fecal samples were taken once a week. All dogs underwent 9 weeks of incremental exercise conditioning where the running distance was designed to increase each week. Every 3 weeks, external telemetry equipment was used to non-invasively measure and record RR and internal BT at resting, working, and post-exercise recovery states. Body composition was measured on weeks −1 and 9 using quantitative magnetic resonance. Body composition, RR, BT, and fecal metabolites were analyzed using a mixed model with dog as a random effect and week and diet group as fixed effects. Dogs on Trt had lower working and post-exercise BT than Ctl (P < 0.05). In addition, Trt dogs had lower recovery BT at weeks 2 and 5 than Ctl dogs (P < 0.05). Treatment dogs had greater fecal short-chain fatty acid concentrations than Ctl (P < 0.05). Diet had no effect on RR or body composition (P > 0.10), but exercise resulted in an overall 7% increase in lean and 3.5% decrease in fat mass (P < 0.05). These data suggest that increasing dietary soluble fiber may positively influence BT and gut health; however, it has no effect on RR or body composition. Soluble fiber did not negatively impact any measures of overall health and performance and should be considered for use in performance dogs.

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