1
|
Rosales AM, Moler JL, Engellant AC, Held AL, Slivka DR. Impact of Topical Capsaicin Cream on Thermoregulation and Perception While Walking in the Cold. Wilderness Environ Med 2024; 35:36-43. [PMID: 38379484 DOI: 10.1177/10806032231223757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
INTRODUCTION Capsaicin, a chili pepper extract, can stimulate increased skin blood flow (SkBF) with a perceived warming sensation on application areas. Larger surface area application may exert a more systemic thermoregulatory response. Capsaicin could assist with maintaining heat transport to the distal extremities, minimizing cold weather injury risk. However, the thermoregulatory and perceptual impact of topical capsaicin cream application prior to exercise in the cold is unknown. METHODS Following application of either a 0.1% capsaicin or control cream to the upper and lower extremities (10 g total, ∼40-50% body surface area), 11 participants in shorts and a t-shirt were exposed to 30 min of cold (0 °C, 40% relative humidity). Exposures comprised of 5 min seated rest, 20 min walking (1.6 m·s-1, 5% grade), and 5 min seated rest. Temperature (skin, core), SkBF, skin conductivity, heart rate, thermal sensation, and thermal comfort were measured throughout. RESULTS The capsaicin treatment did not differ from the control treatment in skin temperature (treatment mean: 30.0 ± 2.5, 30.1 ± 2.4 °C, respectively, p = 0.655), core temperature (treatment mean: 37.3 ± 0.5, 37.4 ± 0.4 °C, respectively, p = 0.113), SkBF (treatment mean: -8.4 ± 10.0, -11.1 ± 10.7 A.U., respectively, p = 0.492), skin conductivity (treatment mean: -0.7 ± 5.1, 0.4 ± 6.4 µS, respectively, p = 0.651), or heart rate (treatment mean: 83 ± 29, 85 ± 28 beats·minute-1, respectively, p = 0.234). The capsaicin and control treatments also did not differ in thermal sensation (p = 0.521) and thermal comfort (p = 0.982), with perceptual outcomes corresponding with feeling "cool" and "just uncomfortable," respectively. CONCLUSIONS 0.1% topical capsaicin application to exposed limbs prior to walking in a cold environment does not alter whole-body thermoregulation or thermal perception.
Collapse
Affiliation(s)
- Alejandro M Rosales
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Jessica L Moler
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Andrew C Engellant
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Alice L Held
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| | - Dustin R Slivka
- School of Integrative Physiology and Athletic Training, Montana Center for Work Physiology and Exercise Metabolism, University of Montana, Missoula, MT, USA
| |
Collapse
|
2
|
Peel J, John K, Page J, Jeffries O, Heffernan SM, Tallent J, Waldron M. Topical application of isolated menthol and combined menthol-capsaicin creams: Exercise tolerance, thermal perception, pain, attentional focus and thermoregulation in the heat. Eur J Sport Sci 2023; 23:2038-2048. [PMID: 37161852 DOI: 10.1080/17461391.2023.2211966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We determined the effects of topically applied (i) isolated menthol cream, (ii) menthol and capsaicin co-application or (iii) placebo cream on exercise tolerance, thermal perception, pain, attentional focus and thermoregulation during exercise in the heat. Ten participants cycled at 70% maximal power output until exhaustion in 35°C and 20% relative humidity after application of (i) 5% isolated menthol, (ii) 5% menthol and 0.025% capsaicin co-application or (iii) placebo cream. Thermo-physiological responses were measured during exercise, with attentional focus and pain determined post-exercise on a 0-to-10 scale. Across the three conditions, time to exhaustion was 13.4 ± 4.8 min, mean ± SD infrared tympanic and skin temperature was 37.2 ± 0.6°C and 35.1 ± 1.2°C, respectively, and heart rate was 152 ± 47 bpm, with no changes between conditions (p > 0.05). Perceived exertion was lower in the isolated menthol vs. all other conditions (p < 0.05, ηp2 = 0.44). Thermal sensation was higher in menthol-capsaicin co-application vs. isolated menthol (p < 0.05, d = 1.1), while sweat rate was higher for capsaicin and menthol co-application compared to menthol (p < 0.05, d = 0.85). The median and interquartile range scores for pain were lower (p < 0.05) in the menthol condition (8, 7-8) compared to both menthol and capsaicin (10, 9-10) and placebo (9, 9-10), which was coupled with a greater distraction (p < 0.05) in the menthol condition (9, 7-10) compared to placebo (6, 5-7). Despite no performance effects for any topical cream application condition, these data reiterate the advantageous perceptual and analgesic role of menthol application and demonstrate no advantage of co-application with capsaicin.HighlightsTopical application of isolated menthol cream to cold-sensitive areas of the body during exhaustive exercise in the heat, elicited reduced perception of pain and enhanced sensation of cooling.While this reduction in generally unpleasant feelings (i.e. pain and heat) were coupled with lower RPE scores in the menthol condition and could be considered beneficial, there was no apparent ergogenic effect in an exercise tolerance test.Co-application of capsaicin and menthol appeared to inhibit the positive sensory effects elicited by menthol.Isolated menthol can induce changes in cognitive processes related to pain and exertion, while also reducing thermal sensation; however, the decision to use menthol creams must be balanced with the limited performance or thermoregulatory effects reported herein during exercise in hot environments.
Collapse
Affiliation(s)
- Jenny Peel
- A-STEM Centre, Faculty of Science & Engineering, Swansea University, Swansea, UK
| | - Kevin John
- A-STEM Centre, Faculty of Science & Engineering, Swansea University, Swansea, UK
| | - Joe Page
- A-STEM Centre, Faculty of Science & Engineering, Swansea University, Swansea, UK
| | - Owen Jeffries
- School of Biomedical, Nutritional and Sport Sciences, Newcastle University, Newcastle Upon Tyne, UK
| | - Shane M Heffernan
- A-STEM Centre, Faculty of Science & Engineering, Swansea University, Swansea, UK
| | - Jamie Tallent
- School of Sport, Rehabilitation, and Exercise Sciences, University of Essex, Colchester, UK
- Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, School of Primary and Allied Health Care, Monash University, Colchester, Australia
| | - Mark Waldron
- A-STEM Centre, Faculty of Science & Engineering, Swansea University, Swansea, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Queensland, Australia
| |
Collapse
|
3
|
Wang X, Xiong Y, Zheng X, Zeng L, Chen J, Chen L, Zhong L, Liu Z, Xu J, Jin Y. Preparation of capsaicin-loaded ultrafine fiber film and its application in the treatment of oral ulcers in rats. Sci Rep 2023; 13:13941. [PMID: 37626141 PMCID: PMC10457293 DOI: 10.1038/s41598-023-40375-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
A drug-loaded diaphragm is an easy-to-use and effective drug delivery system that is often used to treat mouth ulcers. In this study, an ultrafine fiber film loaded with capsaicin was successfully prepared using the electrospinning technology. poly-L-lactic acid and gelatin were selected as the matrix materials to form the composite fiber, and trifluoroethanol was used as a co-solvent for poly-L-lactic acid, gelatin and capsaicin to prepare the spinning solution, which was simple to fabricate. The prepared fiber films were characterized based on their microscopic morphology and tested to derive their mechanical properties. Thereafter, the capsaicin release behavior of the film was investigated. In vitro experiments revealed certain anti-inflammatory and antibacterial abilities while animal experiments revealed that the capsaicin-loaded ultrafine fiber film could promote the healing of oral ulcers in rats. Healing of the tongue tissue in rats administered 10% capsaicin-loaded fiber film was found to be better than that in rats administered the commercial dexamethasone patch. Overall, this development strategy may prove to be promising for the development of oral ulcer patch formulations.
Collapse
Affiliation(s)
- Xue Wang
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Yu Xiong
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Xinxin Zheng
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Liang Zeng
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Jinglin Chen
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Lizhen Chen
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Liping Zhong
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Zhigang Liu
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China
| | - Jia Xu
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China.
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China.
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China.
- Australian Rivers Institute and School of Environment and Science, Griffith University, Nathan, QLD, 4111, Australia.
| | - Youhong Jin
- The Department of Periodontology, The Affiliated Stomatological Hospital of Nanchang University, Nanchang, 330006, Jiangxi, People's Republic of China.
- The Key Laboratory of Oral Biomedicine, Nanchang, 330006, Jiangxi, People's Republic of China.
- Jiangxi Province Clinical Research Center for Oral Diseases, Nanchang, 330006, Jiangxi, People's Republic of China.
| |
Collapse
|
4
|
Jiménez-Martínez P, Alix-Fages C, Janicijevic D, Miras-Moreno S, Chacón-Ventura S, Martín-Olmedo JJ, De La Cruz-Márquez JC, Osuna-Prieto FJ, Jurado-Fasoli L, Amaro-Gahete FJ, García-Ramos A, Colado JC. Effects of phenylcapsaicin on aerobic capacity and physiological parameters in active young males: a randomized, triple-blinded, placebo-controlled, crossover trial. Front Physiol 2023; 14:1190345. [PMID: 37228817 PMCID: PMC10203624 DOI: 10.3389/fphys.2023.1190345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/27/2023] [Indexed: 05/27/2023] Open
Abstract
Objective: Phenylcapsaicin (PC) is a new capsaicin analog which has exhibited a higher bioavailability. This sudy assessed the effects of a low dose (LD) of 0.625 mg and a high dose (HD) of 2.5 mg of PC on aerobic capacity, substrate oxidation, energy metabolism and exercise physiological variables in young males. Materials and methods: Seventeen active males (age = 24.7 ± 6.0 years) enrolled to this randomized, triple-blinded, placebo-controlled, crossover trial. Participants attended the laboratory on 4 sessions separated by 72-96 h. A submaximal exercise test [to determine maximal fat oxidation (MFO) and the intensity at MFO (FATmax)] followed by a maximal incremental test (to determine VO2max) were performed in a preliminary session. The subsequent sessions only differed in the supplement ingested [LD, HD or placebo (PLA)] and consisted of a steady-state test (60 min at FATmax) followed by a maximal incremental test. Energy metabolism, substrate oxidation, heart rate, general (gRPE) and quadriceps (RPEquad) rate of perceived exertion, skin temperature and thermal perception were tested. Results: Clavicle thermal perception was lower in HD compared to PLA and LD (p = 0.04) across time. HD reduced maximum heart rate in comparison to PLA and LD (p = 0.03). LD reported higher general RPE (RPEg) values during the steady-state test compared to PLA and HD across time (p = 0.02). HD and LD elicited higher peak of fat oxidation during the steady-state test compared with PLA (p = 0.05). Intra-test analyses revealed significant differences for fat oxidation (FATox) in favor of HD and LD compared to PLA (p = 0.002 and 0.002, respectively), and for carbohydrate oxidation (CHOox) (p = 0.05) and respiratory exchange ratio (RER) (p = 0.03) for PLA. In the incremental test, only general RPE at 60% of the maximal intensity (W) differed favoring HD (p ≤ 0.05). Conclusion: Therefore, PC may contribute to increase aerobic capacity through the improvement of fat oxidation, maximum heart rate and perceptual responses during exercise.
Collapse
Affiliation(s)
- Pablo Jiménez-Martínez
- Research Group in Prevention and Health in Exercise and Sport (PHES), University of Valencia, Valencia, Spain
- Life Pro Nutrition Research Center, INDIEX, Madrid, Spain
- ICEN Institute, Madrid, Spain
| | - Carlos Alix-Fages
- Research Group in Prevention and Health in Exercise and Sport (PHES), University of Valencia, Valencia, Spain
- Life Pro Nutrition Research Center, INDIEX, Madrid, Spain
- ICEN Institute, Madrid, Spain
- Applied Biomechanics and Sport Technology Research Group, Autonomous University of Madrid, Madrid, Spain
| | - Danica Janicijevic
- Research Academy of Human Biomechanics, The Affiliated Hospital of Medical School of Ningbo University, Ningbo University, Ningbo, China
- Faculty of Sports Science, Ningbo University, Ningbo, China
| | - Sergio Miras-Moreno
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Sara Chacón-Ventura
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Juan J. Martín-Olmedo
- Life Pro Nutrition Research Center, INDIEX, Madrid, Spain
- Department of Physical and Sports Education, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | | | - Francisco J. Osuna-Prieto
- Department of Physical and Sports Education, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
- Research Institute in Health Pere Virgili, University Hospital of Tarragona Joan XXIII, Tarragona, Spain
| | - Lucas Jurado-Fasoli
- Department of Physical and Sports Education, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | - Francisco J. Amaro-Gahete
- Department of Physical and Sports Education, Faculty of Sport Sciences, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | - Amador García-Ramos
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
- Department of Sports Sciences and Physical Conditioning, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Juan C. Colado
- Research Group in Prevention and Health in Exercise and Sport (PHES), University of Valencia, Valencia, Spain
| |
Collapse
|
5
|
Greenfield AM, Alba BK, Giersch GEW, Seeley AD. Sex differences in thermal sensitivity and perception: Implications for behavioral and autonomic thermoregulation. Physiol Behav 2023; 263:114126. [PMID: 36787810 DOI: 10.1016/j.physbeh.2023.114126] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/20/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Temperature sensitive receptors in the skin and deep body enable the detection of the external and internal environment, including the perception of thermal stimuli. Changes in heat balance require autonomic (e.g., sweating) and behavioral (e.g., seeking shade) thermoeffector initiation to maintain thermal homeostasis. Sex differences in body morphology can largely, but not entirely, account for divergent responses in thermoeffector and perceptual responses to environmental stress between men and women. Thus, it has been suggested that innate differences in thermosensation may exist between men and women. Our goal in this review is to summarize the existing literature that investigates localized and whole-body cold and heat exposure pertaining to sex differences in thermal sensitivity and perception, and the interplay between autonomic and behavioral thermoeffector responses. Overall, it appears that local differences in thermal sensitivity and perception are minimized, yet still apparent, when morphological characteristics are well-controlled. Sex differences in the early vasomotor response to environmental stress and subsequent changes in blood flow likely contribute to the heightened thermal awareness observed in women. However, the contribution of thermoreceptors to observed sex differences in thermal perception and thermoeffector function is unclear, as human studies investigating these questions have not been performed.
Collapse
Affiliation(s)
- Andrew M Greenfield
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States of America; Oak Ridge Institute for Science and Education, Belcamp, MD, United States of America.
| | - Billie K Alba
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Gabrielle E W Giersch
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Afton D Seeley
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| |
Collapse
|
6
|
Ravanelli N, Gendron P, Gagnon D. Revisiting the evaluation of central versus peripheral thermoregulatory control in humans. Am J Physiol Regul Integr Comp Physiol 2021; 321:R91-R99. [PMID: 34075801 DOI: 10.1152/ajpregu.00321.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human thermoregulatory control is often evaluated through the relationship between thermoeffector output and core or mean body temperature. In addition to providing a general indication of whether a variable of interest alters thermoregulatory control, this relationship is often used to determine how this alteration may occur. This latter interpretation relies upon two parameters of the thermoeffector output-body temperature relationship: the onset threshold and thermosensitivity. Traditionally, changes in the onset threshold and thermosensitivity are interpreted as "central" or "peripheral" modulation of thermoregulatory control, respectively. This mini-review revisits the origins of the thermoeffector output-body temperature relationship and its use to interpret "central" or "peripheral" modulation of thermoregulatory control. Against this background, we discuss the strengths and weaknesses of this approach and highlight that "central" thermoregulatory control reflects the neural control of body temperature whereas "peripheral" thermoregulatory control reflects properties specific to the thermoeffector organs. We highlight studies that employed more direct approaches to investigate the neural control of body temperature and peripheral properties of thermoeffector organs. We conclude by encouraging future investigations interested in studying thermoregulatory control to more directly investigate the component of the thermoeffector loop under investigation.heat; human; skin blood flow; sweat; thermoregulatory.
Collapse
Affiliation(s)
| | - Philippe Gendron
- Département des Sciences de l'Activité Physique, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada.,Montreal Heart Institute, Montreal, Quebec, Canada
| | - Daniel Gagnon
- Montreal Heart Institute, Montreal, Quebec, Canada.,School of Kinesiology and Exercise Science, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| |
Collapse
|
7
|
Botonis PG, Miliotis PG, Kounalakis SN, Koskolou MD, Geladas ND. Thermoregulatory and cardiovasculareffects of capsaicin application on human skin during dynamic exercise to temperate and warm conditions. Physiol Rep 2019; 7:e14325. [PMID: 31883232 PMCID: PMC6934878 DOI: 10.14814/phy2.14325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Thermoregulatory and cardiovascular responses during cycling in temperate and warm environments without and with application of capsaicin on the skin were investigated. We hypothesized that regardless of environmental temperature, capsaicin application would activate heat loss mechanisms attenuating exercise‐induced rectal temperature (Tre) and blood pressure increase. Eight males cycled at 55% of their maximal aerobic power so long as to reach 38.2°C Tre at 20.8 ± 1.0°C and at 30.6 ± 1.1°C ambient temperatures twice: without (NCA) and with (CA) application of capsaicin patches (12 × 18 cm, 4.8 mg). Patches were applied on pectoralis major, trapezius and vastus lateralis muscles. Thermoregulatory (Tre, proximal‐distal skin temperature gradient, sweating rate), cardiovascular variables and oxygen uptake were continuously recorded. In both ambient conditions, during the first 14 min of exercise, the local vasoconstrictive tone as a function of the relative change in Tre was lower in CA than NCA (p < .05, d = 0.84–1.15). Further, sweating rate was higher and occurred at a lower Tre increase in CA compared to NCA (p = .03, d = 0.6) resulting in extended time to reach 38.2°C Tre (p = .03, d = 0.9). Moreover, oxygen consumption was higher in CA than in NCA (p < .001, d = 0.8). Mean arterial pressure was lower during cycling in warm compared to temperate environment, but was unaffected by capsaicin. We conclude that activation of thermal sensors by capsaicin results in lower Tre rise during exercise, which is mediated through greater skin vasodilation along with higher rate and earlier onset of sweating. Nonetheless, capsaicin application has no extra effect on exercise cardiovascular responses.
Collapse
Affiliation(s)
- Petros G Botonis
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis G Miliotis
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Stylianos N Kounalakis
- Faculty of Physical and Cultural Education, Evelpidon Hellenic Army Academy, Vari, Greece
| | - Maria D Koskolou
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Nickos D Geladas
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| |
Collapse
|