Measure Of Exercise Intensity Research Articles

Myocardial Blood Flow in Newly Diagnosed Breast Cancer Patients at Rest and During Exercise

Heart depends critically on continuous supply of blood, but it is unknown whether cancer, without any treatments, affects myocardial blood flow (MBF) at rest or during exercise. This study therefore aimed at measuring MBF in cancer patients and control subjects and it was hypothesized that MBF is affected by cancer. The study included recently-diagnosed breast cancer patients (n=18) who had not started their oncologic treatments and age-matched female control participants (n=32). Controls were women referred to cardiac diagnostic testing but who were by this testing judged to be free of obstructive coronary artery disease. MBF was quantified with [15O]H2O positron emission tomography (PET) at rest in both groups and additionally during 10-min supine bicycling exercise in the breast cancer patients. Furthermore, cardiac morphological changes were analyzed with a breast cancer mice-model four weeks after the inoculation of 13TC mammary tumor cells. Respective mice without tumors served as controls. Resting heart rate (HR) and rate pressure product (RPP) correlated positively with resting MBF, but were similar in both groups resulting also in similar resting MBF in cancer patients and controls. MBF increased significantly from rest during exercise in breast cancer patients (p<0.0001) and exercising MBF correlated positively with the histologic grade of cancer (r=0.54, p=0.021). However, cancer grade did not associate with exercise intensity measures such as HR, RPP or HR percentage from age-predicted maximal HR. In the mouse model, the breast cancer did not affect heart weight, cardiomyocyte size, myocardial capillary density, or capillary-to-myocyte size ratio. In conclusion, resting MBF in humans or myocardial capillarity in mice appear not to be affected by breast cancer. However, the more severe is the histologic grade of cancer, the higher is the MBF during exercise in patients with breast cancer, independently of the intensity of the exercise suggesting dysregulation of myocardial blood supply with cancer. This novel finding requires further investigations. This study was financially supported by Academy of Finland and Hospital District of South-West Finland. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Feasibility and Usefulness of Repetitions-In-Reserve Scales for Selecting Exercise Intensity: A Scoping Review.

The intensity of resistance training (RT) exercise is an important consideration for determining relevant health and performance-related outcomes. Yet, current objective exercise intensity measures present concerns in terms of viability or cost. In response to these concerns, repetition-in-reserve (RIR) scales may represent an adequate method of measuring and regulating intensity. However, no recent review has focused on how RIR scales have been used for this purpose in prior research. We prepared the present scoping review to analyze the feasibility and usefulness of RIR scales in selecting RT intensity. We conducted a systematic search in PubMed, SPORTDiscus, PsycINFO, and ClinicalTrials.gov databases (last search date April 2023) for experimental and non-experimental studies that utilized an RIR scale to measure proximity to failure in RT activities with apparently healthy individuals of any age. We qualitatively analyzed 31 studies (N = 855 mostly male adult participants) published between 2012-2023. RIR scales appeared to be contextually feasible and useful in prescribing and adjusting RT intensity. The most common trend in this research was to prescribe a target RIR and adjust the exercise load for a desired proximity to muscle failure. Additionally, when measuring proximity to failure as an outcome of interest, the literature suggests that the RIR prediction should be made close to task failure to increase its accuracy. Future research should further explore the impact of sex, RT experience, exercise selection, and muscle conditioning on the overall RIR approach.

Do changes in mood and anxiety mediate exercise-induced reductions in alcohol cravings? An exploratory study.

Exercise is increasingly used as adjunct treatment for alcohol use disorder (AUD). Evidence suggests that moderate-to-high-intensity exercise can ameliorate cravings. We explored the potential mediating effects of changes in mood states in the relationship between exercise intensity and alcohol cravings. Secondary analyses of a nested single-arm trial within a randomized controlled trial (FitForChange). In total, 117 sedentary adults (68.4% female, M = 52 ± 12 years) with clinician diagnosed (Diagnostic and Statistical Manual of Mental Disorders, fifth edition) AUD and indications of craving (Desire for Alcohol Questionnaire) completed a 12-min submaximal cardiorespiratory fitness test on a cycle ergometer. Assessments of craving, mood states (POMS), and state anxiety (STAI-Y1) were taken immediately before, after, and 30 min after exercise. Ratings of perceived exertion (RPE) were included as indirect measures of exercise intensity. The med4way command in Stata was used to explore mediating and interaction effects of improvements in total mood disturbance (TMD) and state anxiety. Improvements in mood and anxiety did not mediate the effect of higher exercise intensity on reductions in alcohol craving. A significant reference interaction was found between "hard" (or greater) exertion and anxiety improvements (β = -1.06, 95% CI [-1.50, -0.61]). Participants whose anxiety reduced during exercise had two times higher odds of reduced cravings when exercising at a higher intensity than participants whose anxiety worsened (OR = 2.04, 95% CI [1.12, 3.72]). Reductions in anxiety may partly explain the positive effect of higher exercise intensity on alcohol cravings. The findings are preliminary and require replication in future studies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Physical Exercise and Health, 2: Benefits Associated With Different Levels and Patterns of Activity.

Physical activity and leisure time exercise are associated with well-documented health benefits. Cohort studies and meta-analyses of such studies show that the benefits of physical activity are dose-dependent, arise at even low levels of activity, improve sharply from low to higher levels of activity, peak at very high levels of activity, and plateau thereafter. The benefits are apparent regardless of how the activity is accrued, from vigorous movements in very short intervals during everyday activities across the course of a day to vigorous, "weekend warrior" exercise, accumulated mostly during 1-2 days in a week. An earlier article in this column discussed terminology, guidance, benefits, and risks in the context of exercise and health. This article states and explains the guidance about exercise for adults and for special populations such as the elderly, discusses general limitations of cohort studies, examines how many steps of walking a day suffice to improve health outcomes and at what level a ceiling is reached, considers at what speed these steps need to accrue, examines the benefits of exercise patterns such as vigorous intermittent lifestyle physical activity and weekend warrior workouts, discusses a study that examined different combinations of exercise, and explains the reasons behind the paradox that fitter persons need to perform apparently harder workouts to meet the exercise guidance. Some niche issues are also discussed, such as a role for isometric exercise, the use of caffeinated and energy beverages before exercise, the use of target heart rate as a measure of exercise intensity, how to grade an exercise session that varies in intensity, and the importance of load-bearing, stability, balancing, and flexibility exercises. It must be understood that exercise is a lifetime commitment that provides benefits that pills cannot. Health care professionals need to recommend activity and discourage sedentariness in all patients whom they see.

O.4.1-10 The FITT guidelines for multicomponent fall prevention programmes for community-dwelling older adults

Abstract Purpose The most commonly proposed intervention for fall prevention in community-dwelling older adults is a multicomponent exercise programme. This is a structured form of exercise that improves muscle performance, balance, proprioception, coordination, mobility, and gait. It usually includes balance and functional exercises versus control. Although it has been suggested that exercise programmes for fall prevention should be performed three or more times per week, no precise guidelines for frequency (F), intensity (I), T(time), and T(type) of a multicomponent exercise programme have been proposed. It has already been pointed out that frequency, type, and time of a multicomponent exercise programme do not explain the effects of balance exercises in older adults. The aim of this systematic review was to evaluate the reporting of FITT guidelines for a multicomponent exercise programme for fall prevention in community-dwelling older adults, with a focus on intensity. Methods Systematic reviews of randomised control trials comparing the effectiveness of structured, multicomponent fall prevention programmes in community-dwelling older adults were included. Studies that focused on a specific condition, such as stroke, were excluded. We included only studies that compared fall rates before and after the multicomponent programme. PubMed, PEDro, EMBASE, Scopus were searched until January 2023. Results Preliminary results showed that FITT guidelines for multicomponent exercise were not consistently reported across studies. In particular, exercise intensity was often not reported. Without a valid and reliable measure of exercise intensity, the dose-response relationship for a multicomponent exercise programme should be further investigated. Conclusions Limitations of this systematic review include variability in the design of multicomponent interventions and incomplete reporting of FITT in reported studies. Support/Funding Source The study is founded from Next Generation EU Recovery and Resilience Facility and resources from National institute of public health Slovenia.

Perceived Exertion Related To Physiological Measures Of Exercise Intensity - Comparing Cycling In Laboratory And Field

Perceived Exertion Related To Physiological Measures Of Exercise Intensity - Comparing Cycling In Laboratory And Field

The talk test as a useful tool to monitor aerobic exercise intensity in healthy population.

The talk test (TT) is subjective method to measure exercise intensity in costless and feasible manner, compared to sophisticated laboratory equipment. We attempted to investigate whether the TT was a valid method for evaluation of exercise intensity, by comparing with values derived from various physiologic markers during cardiopulmonary exercise testing on treadmill in healthy population. A total of 17 healthy subjects (12 males and 5 females) participated in this study. The TT was applied, which consisted of 3-stages difficulties demanding respiratory load while they performed the cardiopulmonary exercise testing on treadmill. In each of the TT stages, ergospirometric and psychophysiologic response marker were collected such as heart rate, oxygen consumption, respiratory exchange ratio, minute ventilation, carbon dioxide output, tidal volume, respiratory rate, and rating of perceived exertion of breathing. Statistical analyses revealed a significant difference of all dependent variables in each of three TT stages, comparing with the resting phase before the TT. The TT showed strong correlation coefficient with all variables except for rating of perceived exertion during the resting phase before the TT. According to increase of exercise intensity, all dependent variables showed a linear tendency with the stages of the TT. Our findings indicated that each of the TT stages was strongly correlated with ergospirometric variables as well as psychophysiologic response during cardiopulmonary exercise testing on treadmill. We suggested that the TT can be used to evaluate and prescribe exercise intensity of aerobic activity in cardiovascular and pulmonary rehabilitation settings.

Monitoring the physical demands of training in Rugby League: The practices and perceptions of practitioners

ABSTRACT The physical demands of elite sport are often monitored with the aim of making evidence-based decisions to enhance performance and reduce injury risk. However, there is limited evidence in rugby league of the monitoring practices and perspectives of practitioners. This study provides a cross-sectional view of practices and perspectives of rugby league practitioners engaged in monitoring the physical demands of training. Practitioners from the Super League, Championship and National Rugby League competitions completed an online survey. Questions related to the tools and measures used to monitor training, along with perceptions of monitoring effectiveness. ‘Enhancing performance’ was considered the most important factor for monitoring training demands with most practitioners using some form of time motion analysis (e.g. GPS) or accelerometers. Nearly all practitioners combined objective external measures of exercise intensity with subjective measures, of which RPE was most common. The monitoring parameters considered most useful were running metrics (high-speed running, total distance covered, and the number of accelerations). Findings suggest that current practices are mostly supported by evidence from research. There was a preference for internal load monitoring tools that are quick and simple, such as RPE. The extent to which training load was monitored was lesser in some Championship teams compared to those in the other competitions, which might be explained by discrepancies in funding and access to players.

The Talk Test to Measure Exercise Intensity in Children

The Talk Test (TT) is a measure of exercise intensity that has been used in a variety of populations. This study extends the use of the TT as a method to measure exercise intensity in prepubertal children. Healthy children performed an incremental exercise test and then either an interval-based exercise session on the treadmill or a 30-min free-play activity session in the gymnasium. The subject read a short (~100 word) passage and responded to “can you speak comfortably?” If the subject was able to speak comfortably, it was recorded as the positive (+) stage of the TT. If the individual was able to speak but with some difficulty, it was recorded as the equivocal stage (+/-). If the subject was unable to speak comfortably, it was recorded as the negative (-) stage. Ventilatory threshold (VT) was determined in the laboratory through respiratory gas exchange. During the interval-based activity and free-play session, the TT was used in the prediction of whether the subject was exercising at an intensity below or above their VT. Data analysis was performed with a chi-squared test for determining statistical significance. In both the interval-based exercise session and the free-play activity, the TT was effective at predicting whether the subject was exercising at an intensity below or above their VT. Correct predictions were made 73.3% of the time for the interval-based exercise group and 81.6% of the time for the free-play session. The TT appears to be a valid predictor of exercise intensity in prepubertal children participating in interval exercise or free play.

Dissonance in views between healthcare professionals and adults with a spinal cord injury with their understanding and interpretation of exercise intensity for exercise prescription

ObjectivesTo evaluate the difference between healthcare professionals (HCPs) and adults with spinal cord injury (SCI) in Asia regarding knowledge and interpretation of ‘exercise intensity’ for aerobic exercise prescription.Methods and study...

Assessment of Exercise Intensity for Uphill Walking in Healthy Adults Performed Indoors and Outdoors.

Borg's rating of perceived exertion (BRPE) scale is a simple, but subjective tool to grade physical strain during exercise. As a result, it is widely used for the prescription of exercise intensity, especially for cardiovascular disease prevention. The purpose of this study was to assess and compare relationships between BRPE and physiological measures of exercise intensity during uphill walking indoors and outdoors. 134 healthy participants [median age: 56 years (IQR 52-63)] completed a maximal graded walking test indoors on a treadmill using the modified Bruce protocol, and a submaximal 1 km outdoor uphill cardio-trekking test (1 km CTT). Heart rate (HR) and oxygen consumption (V̇O2) were continuously measured throughout both tests. BRPE was simultaneously assessed at the end of each increment on the treadmill, while the maximal BRPE value was noted at the end of the 1 km CTT. On the treadmill, BRPE correlated very high with relative HR (%HRmax) (ρ = 0.88, p < 0.001) and V̇O2 (%V̇O2max) (ρ = 0.89, p < 0.001). During the 1 km CTT, a small correlation between BRPE and %HRmax (ρ = 0.24, p < 0.05), respectively %V̇O2max was found (ρ = 0.24, p < 0.05). Criterion validity of BRPE during uphill walking depends on the environment and is higher during a treadmill test compared to a natural environment. Adding sensor-based, objective exercise-intensity parameters such as HR holds promise to improve intensity prescription and health safety during uphill walking in a natural environment.

Digitally enabled cardiac rehabilitation following coronary revascularization: results from a single centre feasibility study.

Wearable activity monitors, together with smartphone-based health and fitness applications (apps), are becoming more accessible and their widespread use provides an additional opportunity for the recording of cardiovascular metrics in patients with cardiovascular disease. The use of selected metrics by cardiac rehabilitation (CR) programmes allows the facilitation of individualized and tailored positive lifestyle changes to patients and places the patient at the centre of their recovery programme. To investigate the role of such devices on outcomes with patients on a CR programme, a cohort/case-control study was conducted. Patients post-myocardial infarction who were treated with either percutaneous coronary intervention or surgical coronary revascularisation at a single centre were invited to use a physical activity monitor linked to a customized app at their initial assessment for the rehabilitation programme. Those who accepted were allocated to the treatment group. The control group was selected from a larger pool of 400 historical and concurrent patients. Propensity matching was used to associate each case with their closest control. The changes in self-reported physical activity were similar for both groups at the end of the CR programme (EOP). The digitally monitored group tended to achieve greater METS (metabolic equivalent of task - a measure of exercise intensity) at 12 weeks (P < 0.059); however, no difference was observed in the overall change in METS at EOP (P < 0.333). Although no difference was noted in diastolic blood pressure, a statistically significant drop in the systolic blood pressure in the digitally monitored group (P < 0.004) was detected. In this study, the innovative combination of technology and face-to-face CR showed promising results and assisted the individualization of delivered content. This intervention could easily be replicated and expanded. Challenges are the recruitment of the elderly population, those who may be less engaged with or have less access to technology, and the underrepresentation of women in the study sample.

Valorization of Natural Cardio Trekking Trails Through Open Innovation for the Promotion of Sustainable Cross-generational Health-Oriented Tourism in the Connect2Move Project: Protocol for a Cross-sectional Study.

BackgroundHiking is one of the most popular forms of exercise in the alpine region. However, besides its health benefits, hiking is the alpine activity with the highest incidence of cardiac events. Most incidents occur due to overexertion or underestimation of the physiological strain of hiking.ObjectiveThis project will establish a standardized cardio trekking test trail to evaluate the exercise capacity of tourists within hiking areas and deliver a tool for the prevention of hiking-associated cardiac incidents. Further, individual exercise intensity for a hiking tour will be predicted and visualized in digital maps.MethodsThis cooperation study between Austria and Germany will first validate a 1-km outdoor cardio trekking test trail at 2 different study sites. Then, exercise intensity measures on 8-km hiking trails will be evaluated during hiking to estimate overall hiking intensity. A total of 144 healthy adults (aged >45 years) will perform a treadmill test in the laboratory and a 1-km hiking test outdoors. They will wear a portable spirometry device that measures gas exchange, as well as heart rate, walking speed, ventilation, GPS location, and altitude throughout the tests. Estimation models for exercise capacity based on measured parameters will be calculated.ResultsThe project “Connect2Move” was funded in December 2019 by the European Regional Development Fund (INTERREG V-A Programme Austria-Bavaria – 2014-2020; Project Number AB296). “Connect2Move” started in January 2020 and runs until the end of June 2022. By the end of April 2022, 162 participants were tested in the laboratory, and of these, 144 were tested outdoors. The data analysis will be completed by the end of June 2022, and results are expected to be published by the end of 2022.ConclusionsIndividual prediction of exercise capacity in healthy individuals with interest in hiking aims at the prevention of hiking-associated cardiovascular events caused by overexertion. Integration of a mathematical equation into existing hiking apps will allow individual hiking route recommendations derived from individual performance on a standardized cardio trekking test trail.Trial RegistrationClinicalTrails.gov NCT05226806; https://clinicaltrials.gov/ct2/show/NCT05226806International Registered Report Identifier (IRRID)DERR1-10.2196/39038

Exercise intensity of active video gaming in cerebral palsy: hip- versus wrist-worn accelerometer data

ABSTRACT Objective The aim of this study was to compare exercise intensity of active video games (AVGs) between hip- and wrist-worn accelerometer data in cerebral palsy (CP). Methods Twenty children and adolescents (9.35 ± 3.71 years) with CP performed two exercise sessions, completing a standardized series of AVGs. Exercise intensity was collected, while one accelerometer was fitted to wrist and hip in separate, counterbalanced sessions. Results Accelerometer counts per minute and cut-points determined were significantly different between the wrist- and hip-worn outputs (p < .001). Metabolic equivalents (METs) of performing AVGs exceeded the three METs moderate intensity threshold in wrist-worn (3.12 ± 0.86) accelerometer and hip-worn data tend to underestimate intensity (1.16 ± 0.08). Conclusions Previous studies showed METs required to perform AVGs were related to moderate intensity (3–6 METs) in CP with mild deficits. Wrist-worn accelerometer, exceeding 3 METs, seem to have higher accuracy in measuring exercise intensity of AVGs than hip-worn.

Sistem Monitoring Kondisi Kesehatan Sebelum dan Sesudah Olahraga Menggunakan Pulse Sensor dan Sensor DS18B20 dengan Metode Naive Bayes

Heart rate and body temperature are essential factors that must be considered before exercise is essential to optimize exercise and know the body's condition. The trainer conducts a health check, and management evaluates the exercise results conducted on the athlete. The Internet of Things is the solution provided to facilitate the monitoring of health conditions and measure exercise intensity. Before and after exercise, the health condition monitoring system is designed to determine the user's health condition by measuring heart rate and body temperature as parameters for decision-making by applying the Naïve Bayes method. The Naive Bayes method is rule-based with the python sci-kit-learn programming language and data communication with MQTT. From the study results, the Sports Health condition monitoring system has succeeded in providing monitoring results, condition prediction decisions, and the accuracy of the Naïve Bayes method by 75%.

Web-based exercise therapy for the treatment of depression

Web-based exercise therapy for the treatment of depression

Modeling Professional Rugby Union Peak Intensity-Duration Relationships Using a Power Law.

Can power law models accurately predict the peak intensities of rugby competition as a function of time? Match movement data were collected from 30 elite and 30 subelite rugby union athletes across competitive seasons, using wearable Global Navigation Satellite Systems and accelerometers. Each athlete's peak rolling mean value of each measure (mean speed, metabolic power, and PlayerLoad™) for 8 durations between 5seconds and 10minutes was predicted by the duration with 4 power law (log-log) models, one for forwards and backs in each half of a typical match. The log of peak exercise intensity and exercise duration (5-600s) displayed strong linear relationships (R2 = .967-.993) across all 3 measures. Rugby backs had greater predicted intensities for shorter durations than forwards, but their intensities declined at a steeper rate as duration increased. Random prediction errors for mean speed, metabolic power, and PlayerLoad were 5% to 6%, 7% to 9%, and 8% to 10% (moderateto large), respectively, for elite players. Systematic prediction errors across the range of durations were trivialto small for elite players, underestimating intensities for shorter (5-10s) and longer (300-600s) durations by 2% to 4% and overestimating 20- to 120-second intensities by 2% to 3%. Random and systematic errors were slightly greater for subelites compared to elites, with ranges of 4% to 12% and 2% to 5%, respectively. Peak intensities of professional rugby union matches can be predicted with adequate precision (trivialto small errors) for prescribing training drills of a given duration, irrespective of playing position, match half, level of competition, or measure of exercise intensity. However, practitioners should be aware of the substantial (moderate to large) prediction errors at the level of the individual player.

Cardiorespiratory Parameters Comparison Between Incremental Protocols Performed in Aquatic and Land Environments by Healthy Individuals: A Systematic Review and Meta-Analysis

Physical properties of water cause physiological changes in the immersed human body compared with the land environment. Understanding the magnitude of cardiorespiratory alterations might ensure adequate intensity control during aquatic exercise programs. We aimed to compare the oxygen uptake (VO2), heart rate (HR), and rating of perceived exertion (RPE) parameters during aquatic and land incremental tests. Four databases (PubMed, LILACS, EMBASE, and SPORTDiscus) were searched in September 2020. Eligibility criteria included studies in a crossover design comparing aquatic and land incremental tests for healthy individuals with at least one of the following parameters: VO2 (maximal, VO2max; anaerobic threshold, VO2AT), HR (HRmax; HRAT), and RPE (RPEmax; RPEAT). The random-effects meta-analysis included mean difference and 95% confidence interval for VO2 and HR or standardized mean difference for RPE. The Joanna Briggs Institute Critical Appraisal tool was adapted to assess methodological quality. Twenty-eight studies were eligible and included in the meta-analysis. Aquatic protocols showed lower values compared with land for VO2max (- 7.07mL.kg-1.min-1; - 8.43 to - 5.70; n = 502), VO2AT (- 6.19mL.kg-1.min-1; - 7.66 to - 4.73; n = 145), HRmax (- 11.71bpm; - 13.84 to - 9.58; n = 503), and HRAT (- 15.29bpm; - 19.05 to - 11.53; n = 145). RPEmax (0.01; - 0.16 to 0.18; n = 299) and RPEAT (- 0.67; - 1.35 to 0.02; n = 55) values were similar between aquatic and land protocols. Our study reinforces the specificity of the environment during incremental tests for prescribing exercises based on physiological parameters as VO2 and HR parameters presented lower values in aquatic protocols than land protocols. Conversely, RPE seems an interchangeable measure of exercise intensity, with similar values during the protocols in both environments. Substantial levels of heterogeneity were present for the VO2max and HRmax meta-analyses, and as such, results should be interpreted with attention. PROTOCOLREGISTRATION: This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42020212508).

Deep learning to predict power output from respiratory inductive plethysmography data

AbstractPower output is one of the most accurate methods for measuring exercise intensity during outdoor endurance sports, since it records the actual effect of the work performed by the muscles over time. However, power meters are expensive and are limited to activity forms where it is possible to embed sensors in the propulsion system such as in cycling. We investigate using breathing to estimate power output during exercise, in order to create a portable method for tracking physical effort that is universally applicable in many activity forms. Breathing can be quantified through respiratory inductive plethysmography (RIP), which entails recording the movement of the rib cage and abdomen caused by breathing, and it enables us to have a portable, non‐invasive device for measuring breathing. RIP signals, heart rate and power output were recorded during a N‐of‐1 study of a person performing a set of workouts on a stationary bike. The recorded data were used to build predictive models through deep learning algorithms. A convolutional neural network (CNN) trained on features derived from RIP signals and heart rate obtained a mean absolute percentage error (MAPE) of 0.20 (ie, 20% average error). The model showed promising capability of estimating correct power levels and reactivity to changes in power output, but the accuracy is significantly lower than that of cycling power meters.

Relationship Between Perceived Exercise Intensity And Natural Killer Cell Mobilization After Exercise

The mobilization of lymphocyte subsets into and out of peripheral blood after dynamic exercise is well-characterized. While the magnitude of this effect has been shown to relate to objective measures of exercise intensity, the role of perceived intensity of the exercise bout is less understood. PURPOSE: Determine if the change in frequency of peripheral blood lymphocytes following acute dynamic exercise is associated with ratings of perceived exertion (RPE). METHODS: 18 physically active adults (8 women, aged 27.7 ± 4.4 years) cycled on a stationary bicycle 30 min at a power sufficient to elicit 80% of their age predicted maximum heart rate (HR). Heart rate and RPE (Borg 6-20 scale) was recorded each minute. Venous blood sampled pre- and post-exercise was analyzed by flow cytometry, and the relative change in lymphocyte subset frequency was calculated post-exercise relative to pre-exercise. The relationship between change in lymphocyte subset frequency with RPE in the final minute of exercise (RPE-end), or HR in final minute of exercise (HR-end), was assessed by linear regression. RESULTS: RPE-end significantly predicted the change in NK-cell frequency post-exercise, where RPE-end was higher in those displaying a greater mobilization (b = 40.41, SE = 17.28, p = .034, R2 = .267). Likewise, RPE-end predicted the increase in cytotoxic CD56dim NK-cells (b = 43.81, SE = 18.73, p = .034, R2 = .267). Analyzing subsets of CD56dim NK-cells differentiated by expression of inhibitory NKG2A and killer cell immunoglobulin-like receptor CD158b revealed RPE-end predicted the change in low- (b = 37.26, SE = 15.77, p = .032, R2 = .271), medium- (b = 43.03, SE = 18.41, p = .034, R2 = .267), and high-differentiated (b = 52.08, SE = 21.78, p = .030, R2 = .276) subsets. RPE-end did not significantly predict change in CD4 or CD8 T-cell subsets. HR-end did not significantly predict change in frequency of any lymphocyte subset. CONCLUSIONS: End of exercise RPE, but not HR, significantly predicted changes in the frequency of NK-cells in peripheral blood post-exercise. Although the current results are limited by the small sample, they suggest a role for the perception of exercise intensity in predicting immune responses to exercise.