Static Exercise Research Articles

Immediate effects of whole-body vibration exposure on perceived exertion and peripheral hemodynamics in overweight and obese individuals

ABSTRACT Objective The study aim was to investigate the immediate effects of whole-body vibration (WBV) exposure in combination with physical exercises on perceived exertion and peripheral hemodynamic responses in overweight and obese individuals. Methods Thirty-six individuals who were overweight or obese (44% males, mean age = 44.17 (9.43) years, mean BMI = 33.29 (3.19) kg/m2) were recruited. Participants were randomly allocated to two groups: control (n = 17) and the WBV (n = 19) group with vibration at 30 Hz and amplitude of 2 mm for a 20-min single vibration session. All participants completed static and dynamic exercises on the sinusoidal-vertical vibration plate but without vibration exposure in the control group. The Borg Rating of Perceived Exertion Scale (RPE) was used to evaluate perceived exertion. Hemodynamic responses were measured with heart rate (HR), arterial blood pressure (aBP) and peripheral capillary oxygen saturation (SpO2) in the pre-WBV, post-WBV, and the recovery period. Results A prolonged increase in perceived exertion was observed in the WBV group (ES = 0.48, p = 0.025), as compared to the control group (ES = 0.10, p = 0.668) in the recovery period. However, the Borg RPE between-groups comparison showed no significant differences in the pre-WBV, post-WBV, and recovery periods. No significant differences in group-time interaction were found for HR, aBP, and SpO2 hemodynamics. Conclusions WBV exposure had no significant positive effect on perceived exertion and hemodynamic responses in overweight and obese individuals.

Effect of dynamic and static strength training on hormonal activity in elite boxers

The aim of this study was to determine hormonal responses to acute and chronic exposure to static and dynamic strength training programs using resistance bands in boxers. 19 male national boxers participated in the study. Boxers were instructed to perform strength exercises with resistance bands for 3 days a week for 8 weeks involving either dynamic (n=10) or static (n=9) resistance exercises. Blood samples were taken before exercise, immediately after the initial exercise session, and 8 weeks later following the last exercise session. Cortisol, growth hormone, adrenocorticotropic hormone adrenaline and noradrenaline levels were measured. Statistical analyses involved non-parametric analysis with an alpha level of .05. Dynamic strength exercises were effective stimuli to growth hormone, adrenaline and noradrenaline, while static strength exercises provoked cortisol, growth hormone, adrenaline and noradrenaline responses both initially after exercise and after 8 weeks of chronic training. Neither dynamic nor static strength exercises were effective in prompting adrenocorticotropic changes after an exercise session or after 8 weeks of training. We showed that dynamic and static strength exercise protocols using resistance bands both could provoke acute and chronic hormonal responses in boxers similar to more traditional modes of such exercise.

Facial Blood Flow Responses to Dynamic Exercise.

We reported previously that a static handgrip exercise evoked regional differences in the facial blood flow. The present study examined whether regional differences in facial blood flow are also evoked during dynamic exercise. Facial blood flow was measured by laser speckle flowgraphy during 15 min of cycling exercise at heart rates of 120 bpm, 140 bpm and 160 bpm in 12 subjects. The facial vascular conductance index was calculated from the blood flow and mean arterial pressure. The regional blood flow and conductance index values were determined in the forehead, eyelid, nose, cheek, ear and lip. One-way ANOVA and Tukey's post-hoc test were used to examine effects of exercise intensity and target regions. The blood flow and conductance index in skin areas increased significantly with the exercise intensity. The blood flow and conductance index in the lip increased significantly at 120 bpm and 140 bpm compared to the control, while the values in the lip at 160 bpm did not change from the control values. These results suggest that the blood flow in facial skin areas, not in the lip, responds similarly to dynamic exercise, in contrast to the responses to static exercise.

The effect of static and dynamic core exercises on dynamic balance, spinal stability, and hip mobility in female office workers.

Objectives This study aims to compare the effect of static and dynamic core exercises in terms of dynamic balance, spinal stability, and hip mobility in female office workers.Patients and methods Between May 2018 and June 2018, a total of 34 women (mean age 36.4±6.5 years; range, 28 to 54 years) who worked for a bank and exercised in the fitness center of the work place were recruited. The women were divided into two groups including 17 women in each as static and dynamic core groups and administered sessions of 20 to 30 min twice a week for six weeks. Both groups were tested for dynamic balance (Y-balance test), spinal stability (functional reach test), and hip mobility (active flexion and extension) before and after six weeks of exercise.Results A statistically significant improvement was found in both groups between the pre- and post-test results in terms of spinal stability, hip mobility, and dynamic balance (p<0.05). The only exception was the right and left leg anterior balance in the static core group. Dynamic core exercises seemed to be more effective than static core exercises in improving the right and left leg anterior balance. There were no statistically significant differences between the groups in terms of spinal stability, hip mobility, and dynamic balance according to the mean absolute change (p>0.05).ConclusionOur study results indicate that both types of exercises are effective in improving dynamic balance, spinal stability, and hip mobility in female office workers. Therefore, the expected benefits from core exercises are to enhance dynamic balance, spinal stability, and hip mobility. Female workers can perform both types of exercises safely and effectively.

Investigation of Static and Dynamic Balance in School Basketball Players with a History of Ankle Injury

Objective: This study aimed to investigate the static and dynamic balance in basketball students with an ankle injury history. Methods: Subjects of this study were 36 elementary school basketball male students who participated in this study purposefully and voluntarily. Subjects were divided into two groups of 18 people with an ankle injury and the control group without ankle injury. To measure the static balance from the stork test and the dynamic balance from the star test was used. Descriptive statistics (mean and standard deviation) and inferential statistics (Shapiro-Wilk test and independent t-test) were used to analyze the results. Results: There was a significant difference between the static balance of basketball students and the control group (P=0.001), but no significant difference was found between basketball studentschr('39') dynamic balance with ankle injuries and the control group (P=0.0887). Conclusion: Based on research results, it can be concluded that lower limb injuries, especially ankle injuries they can influence postural control and static balance of basketball students and caused some functional disability. Also recommended coaches during the sports era of basketball players to design specific exercises to strengthen ankle muscles and ligaments and use static balance exercises not to witness this type of injury.

How may alternative drug policy settings influence criminal charges? A longitudinal study of cannabis patients and a general population sample

BackgroundThis study examines criminal charges amongst cannabis use disorder (CUD) patients and a matched sample in a setting of drug criminalization, and simulates the effect of policy changes on the proportion obtaining a criminal record and on the number of charges for those being charged. MethodsAll CUD patients entering specialist treatment in Norway in 2009–2010 (n=3,951) were included from the Norwegian Patient Registry and a random sample matched on age and gender drawn from the general population by Statistics Norway (n=7,902). Data were linked to the Norwegian Crime Registry (2009–2014).The nature and extent of all charges were examined. A static simulation exercise assessed the hypothetical effect on charges if a) all charges for use and possession of illicit drugs were eliminated (“decriminalization”) and b) in addition, all charges for cultivation, manufacturing, and sales were eliminated (“legalization”). ResultsTwo thirds (66%) of patients and 12% of matched sample were charged during the observation period. While the most common offence for patients was drug law violations (52%), relatively few (14%) had no other charges. Road traffic violations was the most common offence for the matched sample and 1.2% were charged with drug offences only. The mean number of charges were 9 for the patients and 3 for the matched sample.Simulations suggest that decriminalization may decrease the proportion being charged by 8% for patients and 4% for the matched sample under “decriminalization”, compared to 24% and 11%, respectively if all drugs were legalized. The number of charges for patients and non-patients would drop by 23% and 13% respectively, while legalization may decrease the number of charges by 46% and 25%, respectively. ConclusionThe simulations suggest that the impacts of decriminalisation and legalisation on the proportion being charged are relatively modest, while the policy changes are likely to lead to substantial reductions in the number of charges for both the patient and non-patient groups.

COVID-19 — Is It Time for Exercise Clinicians to Prehabilitate “High Risk” Respiratory Patients?

COVID-19 — Is It Time for Exercise Clinicians to Prehabilitate “High Risk” Respiratory Patients?

Impact Of Vibration On Rectus Femoris During Bodyweight Squats In Female Collegiate Track Athletes

Whole-body vibration (WBV) exposes the entire body to mechanical oscillations when one is standing on a vibrating platform. In recent years, researchers have studied the extent to which these oscillations effect the body. Previous studies have investigated muscle activity in the general population during static exercises with WBV, but there has been little research that has focused on the effects of WBV during dynamic movements in athletes. PURPOSE: The purpose of the study was to investigate the effects of WBV on rectus femoris muscle activity during a whole-body squat (WBS) exercise in NCAA Division 1 female track and field athletes. METHODS: Fifteen NCAA Division 1 track and field female athletes (Height = 165.20+7.85 cm; Weight = 61.11+9.46 kg; BF% = 18.80+4.92 %; Age = 19.80+1.57 years) were assessed for adequate squat form using the FMS deep squat protocol. Subjects then completed a dynamic warm-up before a wired EMG sensor was placed over the rectus femoris muscle belly of the right leg. Subjects completed two trials consisting of 10 repetitions of WBS with and without WBV, in a counterbalanced order. Root mean squared (RMS) values were collected using the EMG sensor during WBS trials. RMS values for WBS during each trial were analyzed using a Dependent t-Test with an alpha level of p< 0.05. RESULTS: Mean values for RMS were 74.92+22.81 μV for WBV trials, and 53.11+24.46 μV for ground squat trials. The values for RMS were significantly (p < 0.001) greater for the WBV trials. CONCLUSIONS: Significantly higher RMS values occurred for the WBV trials which may indicate that more motor units were recruited in the rectus femoris when the athlete was performing WBS and experiencing WBV. Future research may be required to determine if the current study’s results may apply to collegiate male track and field athletes.

Symptom And Physiological Response To Exercise Following Concussion

Exercise can exacerbate concussion symptoms, even when symptom are not apparent at rest. Whether this relates to a physiologic response to exercise remains unknown. PURPOSE: To examine symptom and physiologic responses to a stationary bike exercise protocol among participants with concussion and uninjured controls. METHODS: 32 concussed individuals (age=16.9±2 years; 50% female; 12.4±5 days post-injury) and 22 healthy controls (age=18.3±2 years; 59% female) completed a modified YMCA branching exercise protocol. After warmup (3 mins; 50 watts), participants progressed to Stage 1 (3 mins; 100 watts). Stage 2 was based on Stage 1 HR (2 mins; 175 watts if <60% age predicted HR; 150 watts if 60-70% age predicted HR; 125 watts if >70% age predicted max HR). Stages 3-5 lasted 2 mins, and increased by 50 watts/stage. Stopping criteria were symptom worsening (visual analog scale [VAS, 0 - 100] change>30) or 85% age-predicted HR. We assessed changes (end - baseline) for VAS, HR, systolic/diastolic blood pressure (SBP/DBP), rating of perceived exertion (RPE), carbon dioxide output (VCO2), respiratory exchange ratio (RER), and oxygen consumption (VO2)]. RESULTS: The concussion group reported significantly higher symptom severity at rest than controls (21.0±19.6 vs. 5.6±5.6; p=0.002). Resting HR (63.4±9.8 vs. 64.6±7.3) and protocol duration (11.3±2.0 vs. 11.5±1.3 minutes) were similar between groups. 22% of concussed participants stopped due to symptom exacerbation. Symptom change was not significantly different between groups (VAS= 10.4±16.1 vs. 4.7±11.2; p=0.18). The control group had significantly larger increase in DBP than the concussion group (6.1±5.7 vs. 1.4±4.8; p=0.003). VAS change was significantly associated with HR change among concussed (β=-0.45; 95% CI=-0.87, -0.02; p=0.04) and control groups (β=0.67; 95% CI=0.18, 1.17), and for control subjects, VAS change was associated with RPE (β=2.9; 95% CI=0.55, 5.22; p=0.02) and SPB (β=-0.73; 95% CI= -0.97, -0.48; p<0.001) changes. CONCLUSIONS: Using a branching bike-based exercise protocol, most participants achieved 85% age-predicted maximum HR, rather than symptom exacerbation. The amount of symptom provocation between groups was similar. Greater HR changes during exercise were associated with greater symptom provocation independent of group.

Determination of the functional state of the body using non-traditional research methods when performing the static exercise: "Prone press ups, static top position" (Cobra)

Material and methods. Investigation of the effect of the selected static exercise was performed using the method of determining the electrical conductivity of representative points of the human body. Ten female students of 18-20 years who perfectly mastered the technique of performing the exercise were surveyed. The measurements were performed during, after and after 6 minutes.&#x0D; Results. Significant changes in indicators of electrical activity in representative points of the human body were revealed. Selected static exercise has a significant impact on the functional state of the person: according to Chinese folk medicine, stimulates the body points corresponding to the acupuncture meridians according to the classification of Chinese medicine cardiovascular, lymphatic and immune systems, colon and submucosa, mucosa spleen, small intestine.&#x0D; Conclusions. During the study of the effect of static exercise, it was found that the increase of electrical activity of the human body points, which, according to the literature, are responsible for the functions of the respiratory, cardiovascular, lymphatic and immune systems, the large intestine. This exercise also causes a decrease in electrical activity at representative points of the liver, stomach, and inhibits the activity of the small intestine, spleen, and pancreas. It is possible to propose the use of methods for determining the activity of human body points for the study of the influence of static exercises on the human body, along with other generally accepted scientific methods.

Determination of the functional state of the body using non-traditional research methods when performing the static exercise: "Prone press ups, static top position" (Cobra)

&lt;p&gt;&lt;strong&gt;The aim&lt;/strong&gt; of the work was to determine the electrical activity of the skin when performing a static exercise "Prone press ups, static top position (Cobra) ".&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Material and methods&lt;/strong&gt;. Investigation of the effect of the selected static exercise was performed using the method of determining the electrical conductivity of representative points of the human body. Ten female students of 18-20 years who perfectly mastered the technique of performing the exercise were surveyed. The measurements were performed during, after and after 6 minutes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results.&lt;/strong&gt; Significant changes in indicators of electrical activity in representative points of the human body were revealed. Selected static exercise has a significant impact on the functional state of the person: according to Chinese folk medicine, stimulates the body points corresponding to the acupuncture meridians according to the classification of Chinese medicine cardiovascular, lymphatic and immune systems, colon and submucosa, mucosa spleen, small intestine.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions&lt;/strong&gt;. During the study of the effect of static exercise, it was found that the increase of electrical activity of the human body points, which, according to the literature, are responsible for the functions of the respiratory, cardiovascular, lymphatic and immune systems, the large intestine. This exercise also causes a decrease in electrical activity at representative points of the liver, stomach, and inhibits the activity of the small intestine, spleen, and pancreas. It is possible to propose the use of methods for determining the activity of human body points for the study of the influence of static exercises on the human body, along with other generally accepted scientific methods.&lt;/p&gt;

Factores determinantes del equilibrio en mujeres mayores: la salud mental y la edad

Las mujeres mayores se consideran potencialmente más frágiles que los varones. Este estado conlleva un mayor riesgo de sufrir caídas. A su vez, la salud mental está directamente relacionada con el equilibrio, y por tanto con las caídas. Los objetivos planteados fueron: a) determinar la relación entre el equilibrio estático y el dinámico con el estado de salud mental y la edad de mujeres mayores físicamente independientes, b) analizar las diferencias en los parámetros físicos y mentales analizados en función de la presencia o no de deterioro cognitivo. Se invitó a participar a 120 mujeres de entre 60 y 80 años. Para determinar su independencia funcional se utilizó la escala de Katz. La función cognitiva fue medida con el test Mini-Mental State. El equilibrio estático monopodal (EEM) se valoró con el test de permanecer sobre una pierna. Para medir el equilibrio dinámico se utilizó el test funcional Timed Up and Go. 103 mujeres fueron incluidas en el estudio. El estado de salud mental se relaciona directamente con el índice de Katz (r² = 0,00317) y el EEM (r² = 0,132), e inversamente con la edad (r² = 0,0509) y el equilibrio dinámico (r² = 0,0822). La edad se relaciona directamente con equilibrio dinámico (r² = 0,115) e inversamente con índice de Katz (r² = 0,009) y el EEM (r² = 0,175). Se encontraron diferencias significativas en el índice de Katz (P =0,01), el estado de salud mental (P&lt;0,001), el EEM (P =0,004) y el equilibrio dinámico (P =0,03) entre los grupos con y sin deterioro cognitivo. Se puede concluir que tanto la edad como la salud mental son predictoras de un buen equilibrio estático monopodal y dinámico en una muestra de mujeres mayores. Se recomienda realizar ejercicios de estimulación cognitiva y equilibrio estático y dinámico.

The Investigation of the Effect of Static and Dynamic Core Training on Performance on Football Players

This study was carried out to investigate the effect of static and dynamic core training on the performance of football players. In this study, static and dynamically applied core exercises were evaluated in terms of speed and agility in football players, and then their effects on anaerobic power tests, core stabilization tests and body composition were compared. While 10 of the 30 football players participating in the study were practicing dynamic core exercises and 10 of them were practicing static core exercises 2 days a week for about 9 weeks and 30 minutes a day, 10 athletes continued their football training with the other group athletes as control groups. The effects of the exercises, performed at the end of 9 weeks on performance, body composition, and core stabilization tests were compared in the pre and post-test in order (p<0.05). There is no significant difference in the height, body weight, body mass index parameters of 30 subjects (10 control, 10 static core, 10 dynamic core) belonging to the 3 groups participating in the study. Significant differences were found at waist level and hip circumference at the level of p<0.05 in comparisons between the first and last measurements of all anthropometric measurements. While there was a significant increase in the duration of leg lift, push-up, plank, shuttle, and isometric tests, a decrease was observed in the plank, shuttle and isometric test times in the control group. In the pre and post-test comparisons, 30 m speed, long jump, vertical jump, agility 550 and arrowhead agility tests showed a significant difference at p<0.05 level. It can be said that core studies should be included in training aimed at increasing performance in the football branch.

Features of electromyographic changes in patients with upper limb lesions during various exercise types performance

For the first time in clinical conditions a study was carried out for estimation of average amplitude (AA-EMG) and frequency of oscillations repetitions parameters during dynamic and static exercises performance. We found that in healthy individuals EMG amplitude depends on the character of physical exercises performed. The largest EMG amplitude was registered when performing static exercises. It was found that in acute stroke patients, while performing flexion and extension of fingers, low-amplitude EMG activity was registered stretched for entire movement cycle without a clear peak of extremum. When performing static exercises, the amplitude and frequency of EMG oscillations changed significantly in a positive way.

Endothelial function in response to exercise in the cold in patients with coronary artery disease.

Regular long-term physical exercise has favourable effects on endothelial function in patients with coronary artery disease (CAD). However, the effects of an acute exercise bout in the cold on endothelial function are not known. At first, the effects of moderate-intensity aerobic lower-body exercise were assessed in CAD patients (n=16) in a neutral [+22°C] and cold [-15°C] environment. Secondly, responses to static and dynamic upper-body exercise in a neutral [+22°C] and cold [-15°C] environment were investigated in CAD patients (n=15). All experiments were performed in a random order. Endothelial function was measured by flow-mediated dilation (FMD) of the brachial artery in response to reactive hyperaemia, before and after the exposures in a neutral environment. No significant temperature*exercise*condition (pre-post) interaction was observed in FMD% when comparing rest versus aerobic exercise or static versus dynamic upper-body exercise. Relative reactive hyperaemia during FMD protocol, measured by changes in shear rate, was elevated after rest compared to aerobic exercise (p=.001) and after static compared to dynamic upper-body exercise (p<.001). However, no significant temperature*exercise*condition interaction was observed when FMD% was normalizedfor shear rate. Endothelial function to an acute bout of exercise among CAD patients was not modified by the environmental temperature where the exercise was performed. The present findings argue against the hypothesis that exercise in cold environmental conditions impairs endothelial function in patients with CAD.

High Intensity Interval Exercise Increases Platelet and Transforming Growth Factor‐β Yield in Platelet‐Rich Plasma

Platelet-rich plasma (PRP) is an emerging orthobiologic treatment for musculoskeletal conditions like osteoarthritis. Two studies have demonstrated the influence of longer duration exercise on PRP composition, but no study has ever explored the impact of high intensity interval exercise (HIIE) on PRP content. To quantify cellular and growth factor content changes in PRP after 4 minutes of HIIE. Controlled laboratory pilot study. Academic sports medicine center. Ten healthy volunteers (5 male, 5 female). Volunteers had PRP prepared from 15 mL of whole blood using a single spin, plasma-based system (autologous conditioned plasma [ACP]) immediately before and after 4 minutes of HIIE on a stationary exercise bike (Tabata protocol). The PRP was sent for complete blood counts and enzyme-linked immunosorbent assay (ELISA) to quantify transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), insulin-like growth factor (IGF)-1, and vascular endothelial growth factor (VEGF). Mean platelet count in PRP increased from 367.4 ± 57.5 k/μL to 497.7 ± 93.3 k/μL after 4 minutes of HIIE (P < .001). TGF-β also increased from 8237.2 ± 7676.5 pg/mL to 21 535.7 ± 4062.6 pg/mL postexercise (P = .004). The other cellular components (leukocytes, red blood cells, and mean platelet volume) and growth factors (PDGF, IGF-1, and VEGF) were not significantly changed. A short 4-minute bout of HIIE significantly increased the total platelet count and TGF-β concentration in PRP.

Heart rate variability in different intensities of static and dynamic exercises graded using similar heart rate

The intensity and the type of the cardiovascular responses differ depending on the exercise type and intensity and the muscle groups involved. However, the responses in static and dynamic exercises are hardly comparable since the protocol used for grading the intensity of these exercises are different. Thus, we compared the cardiovascular autonomic responses in dynamic and static exercises of same muscle groups at increasing intensities graded using similar heart rate. 32 subjects performed dynamic and static exercises of lower limbs at 50% (HR50max) and 60% (HR60max) of their maximum achievable heart rates. Continuous ECG was recorded for 2 min during the exercise. Target heart rate specific single beat R–R intervals were extracted from the recorded ECG, and heart rate variability was determined. A factorial two way analysis of variance was conducted on the influence of two independent variables (load and exercise type) on the heart rate variability during different manoeuvres with baseline values taken as covariates. Exercise load had a main effect on HFnu and RMSSD. HFnu increased (p = 0.001) while RMSSD decreased (p = 0.025) with an increase in the exercise load. Exercise type also had a main effect on RMSSD with RMSSD being higher in dynamic exercise (p = 0.028). With increased load, LFnu decreased in dynamic exercise but was maintained in static exercise. Time domain parameter RMSSD decreases with an increase in the exercise load indicating a decrease in vagal modulation of heart rate with an increase in exercise load. RMSSD is more in dynamic exercise compared with static exercise indicating higher vagal modulation in dynamic exercise. However, increase in HFnu with exercise load may be due to the influence of increased ventilation on heart rate modulation.

Development of Micro-Mobility Based on Piezoelectric Energy Harvesting for Smart City Applications

This study investigates the use of an alternative energy source in the production of electric energy to meet the increasing energy requirements, encourage the use of clean energy, and thus reduce the effects of global warming. The alternative energy source used is a mechanical energy by piezoelectric material, which can convert mechanical energy into electrical energy, that can convert mechanical energy from pressure forces and vibrations during activities such as walking and traveling into electrical energy. Herein, a pilot device is designed, involving the modification of a bicycle into a stationary exercise bike with a piezoelectric generator, to study energy conversion and storage generated from using the bike. Secondly, the piezoelectric energy harvesting system is used on bicycles as a micro-mobility, light electric utility vehicle with smart operation, providing a novel approach to smart city design. The results show that the energy harvested from the piezoelectric devices can be stored in a 3200 mAh, 5 V battery and power sensors on the bicycle. Moreover, 13.6 mW power can be generated at regular cycling speed, outputting 11.5 V and 1.2 mA. Therefore, the piezoelectric energy harvesting system has sufficient potential for application as a renewable energy source that can be used with low power equipment.

One‐Time Acute Elevation of Muscle Temperature Is Effective for Attenuation of Exaggerated Exercise Pressor Reflex in Rats with Peripheral Artery Disease

BackgroundThe blood pressure (BP) response is augmented during static exercise in peripheral artery disease (PAD). Heating treatment was found to be effective for the attenuation of the BP response in PAD patients. However the underlying mechanism for the muscle temperature (Tm) on BP responses in PAD is still unclear.AimsWe first determined the effect of one‐time acute Tm elevation on the exaggerated exercise pressor reflex in PAD rats with 72 hours of femoral artery occlusion. We further determined if P2X receptor was engaged during this process because a lower Tm in occluded muscle can alter expression and function of P2X.MethodsThe BP response to static muscle contraction was recorded to examine the exercise pressor reflex. Also, αβ‐methylene ATP (αβ‐me ATP) was injected into the arterial blood supply of the hindlimb muscles to stimulate P2X receptors in the muscle afferent nerves. To elevate the Tm, a heating pad was placed locally on the hindlimb and the Tm was increased by ~1.5 °C. Then the Tm was stabilized and maintained for 5 min.ResultsThe BP response to static muscle contraction was examined 20 minutes before (pre‐heat), immediately following (acute heat) and 20 minutes after the end of elevation of Tm (recovery). Compared with control rats, a greater mean arterial pressure (MAP) response was observed in PAD rats in the pre‐heat session (27.50±2.07 mmHg in PAD rats/n=12 vs. 18.00±1.67 mmHg in control rats/n=9; P&lt;0.05). However, following elevation of the Tm, the amplification of MAP response was similar in PAD rats and in control rats (21.25±3.00 mmHg in PAD rats/n=12 vs. 18.00±2.56 mmHg in control rats/n=8; P&gt;0.05). During the recovery, a greater MAP response remained in PAD rats (27.54±0.90 mmHg in PAD rats/n=11 vs. 20.14±1.43 mmHg in control rats/n=7; P&lt;0.05). Note that no significant difference in developed muscle tension during contraction was seen in control rats and PAD rats (P&gt;0.05). When αβ‐me ATP (0.125mM) was given, the MAP responses were higher in PAD rats (n=7) than in control rats (n=7) (56.03±4.70 mmHg in PAD vs. 39.12±4.59 mmHg in control for pre‐heat, 59.63±3.55 mmHg in PAD vs. 39.92±5.20 mmHg in control after heating, and 63.33±2.51 mmHg in PAD vs. 35.57±4.38 mmHg in control for recovery; P&lt;0.05 for all sessions between two groups).ConclusionOne‐time acute elevation of the Tm inhibits the exaggeration of the exercise pressor reflex in PAD rats. The effects of one‐time heat may not be through alternating muscle afferent nerves’ P2X receptors.Support or Funding InformationThis study was supported by NIH P01 HL134609 &amp; R01 HL141198

Hypercapnia augments resistive exercise-induced elevations in intraocular pressure in older individuals.

What is the central question of this study? Astronauts on-board the International Space Station (ISS) perform daily exercises designed to prevent muscle atrophy and bone demineralization: what is the effect of resistive exercise performed by subjects while exposed to the same level of hypercapnia as on the ISS on intraocular pressure (IOP)? What is the main finding and its importance? The static exercise-induced elevation in IOP during 6° prone head-down tilt (simulating the headward shift of body fluids in microgravity) is augmented by hypercapnia and exceeds the ocular hypertension threshold. The present study assessed the effect of 6° head-down (establishing the cephalad fluid displacement noted in astronauts in microgravity) prone (simulating the effect on the eye) tilt during rest and exercise (simulating exercise performed by astronauts to mitigate the sarcopenia induced by unloading of weight-bearing limbs), in normocapnic and hypercapnic conditions (the latter simulating conditions on the International Space Station) on intraocular pressure (IOP). Volunteers (mean age=57.8±6 years, n=10) participated in two experimental sessions, each comprising: (i) 10min rest, (ii) 3min static handgrip exercise (30% max), and (iii) 2min recovery, inspiring either room air (NCAP) or a hypercapnic mixture (1% CO2 , HCAP). We measured IOP in the right eye, cardiac output (CO), stroke volume (SV), heart rate (HR) and mean arterial pressure (MAP) at regular intervals. Baseline IOP in the upright seated position while breathing room air was 14.1±2.9mmHg. Prone 6° head-down tilt significantly (P<0.01) elevated IOP in all three phases of the NCAP (rest: 27.0±3.7mmHg; exercise: 32.2±4.8mmHg; recovery: 27.4±4.0mmHg) and HCAP (rest: 27.3±4.3mmHg; exercise: 34.2±6.0mmHg; recovery: 29.1±5.8mmHg) trials, with hypercapnia augmenting the exercise-induced elevation in IOP (P<0.01). CO, SV, HR and MAP were significantly increased during handgrip dynamometry, but there was no effect of hypercapnia. The observed IOP measured during prone 6° HDT in all phases of the NCAP and HCAP trials exceeded the threshold pressure defining ocular hypertension. The exercise-induced increase in IOP is exacerbated by hypercapnia.