Cardiac Rehabilitation Knowledge and Attitudes of Cardiology Fellows.

PURPOSE: Cardiac rehabilitation (CR) is underutilized with only 8-31% of eligible patients participating. Lack of referral and lack of physician endorsement are well-known barriers to participation. Physicians who lack insights regarding CR are less likely to refer patients and recommend it. Cardiology fellows are early career physicians who spend a significant amount of time treating patients eligible for CR. At one institution's cardiology fellowship program, we sought to assess fellow attitudes and knowledge base regarding CR and to determine their facilitators and barriers to CR endorsement and referral. METHODS: University of Pittsburgh Department of Medicine Cardiology fellows were surveyed and interviewed to assess CR knowledge, attitudes, and perceived facilitators and barriers to CR endorsement and referral. RESULTS: The cardiology fellows at this institution had strong belief in the benefits and cost-effectiveness of CR. Despite their support of CR, they had low CR knowledge scores. Perceived impediments to CR included complicated logistics of CR operations, limited communication between CR staff and fellows, limited time with patients, presumed patient barriers, perceived self-barriers, and poor understanding of referral processes (particularly as they varied in each hospital in which they rotated). Perceived supports to CR included greater awareness of evidence-based outcomes, awareness of patient-centered outcomes, pre-arranged order sets, and reminders for referral. CONCLUSION: This study revealed perceptions of cardiology fellows at one institution regarding CR that have not been considered previously. Key barriers to endorsement and referral to CR were exposed as well as opportunities to overcome them. Fellowship training affords an important opportunity to improve CR education, and to potentially improve participation of eligible patients for this important aspect of care.

Are Heart Rate and Rating of Perceived Exertion Effective to Control Indoor Cycling Intensity?

Indoor cycling's popularity is related to the combination of music and exercise leading to higher levels of exercise intensity. It was our objective to determine the efficacy of heart rate and rating of perceived exertion in controlling the intensity of indoor cycling classes and to quantify their association with oxygen uptake. Twelve experienced males performed three indoor cycling sessions of 45 min that differed in the way the intensity was controlled: (i) oxygen uptake; (ii) heart rate; and (iii) rating of perceived exertion using the OMNI-Cycling. The oxygen uptake levels were significantly higher (p = 0.007; µp2 = 0.254) in oxygen uptake than heart rate sessions. Oxygen uptake related to body mass was significantly higher (p < 0.005) in the oxygen uptake sessions compared with other sessions. Strong correlations were observed between oxygen uptake mean in the oxygen uptake and rating of perceived exertion sessions (r =0.986, p < 0.0001) and between oxygen uptake mean in the oxygen uptake and heart rate sessions (r = 0.977, p < 0.0001). Both heart rate and rating of perceived exertion are effective in controlling the intensity of indoor cycling classes in experienced subjects. However, the use of rating of perceived exertion is easier to use and does not require special instrumentation.

Affective and metabolic responses to self-selected intensity cycle exercise in young men.

Self-selected intensity exercise has resulted in greater affective responses (AR) compared to prescribed exercise of similar intensity and many individuals self-select intensity at a moderate level identified by metabolic analysis. As such, self-selected intensity may be an effective alternative for exercise prescription designed to promote adherence and result in health and fitness benefits. Self-selected intensity has not been well described for many subject populations and exercise modes. Therefore, the purpose of this investigation was to measure affective and metabolic responses during self-selected intensity cycle exercise in college-aged men. Thirty-three men (22.4 ±â€¯2.2 yr) performed a peak oxygen consumption test and a 20 min self-selected trial on a cycle ergometer on separate days. Oxygen consumption (VO2) was measured continuously throughout both exercise sessions. AR were measured using the Feeling Scale and ratings of perceived exertion (RPE) using the OMNI Scale every 5 min during the self-selected trial. χ2 analysis was used to determine if a significant proportion of subjects self-selected intensity above 50% VO2 reserve (VO2R), defined as a threshold for moderate-intensity exercise and potential cardiorespiratory fitness benefits by American College of Sports Medicine. Mean self-selected intensity was 57.6 ±â€¯11.1%VO2peak and 89.3 ±â€¯20.2% of ventilatory threshold. Twenty eight of 33 subjects self-selected intensity above 50% VO2R (p < .05). Self-selected intensity was associated with positive AR (1.8 ±â€¯1.4) and mean RPE of 4.0 ±â€¯1.5. In college-aged men, self-selected intensity cycle exercise was performed at a moderate intensity level and elicited positive AR for most subjects. Therefore, self-selected intensity could be an effective component of an exercise prescription for this population.

Evaluating Energy Expenditure Estimated by Wearable Technology During Variable Intensity Activity on Female Collegiate Athletes.

Monitoring an athlete's energy intake and energy expenditure (EE) is an important consideration of nutritional planning for sport conditioning and peak performance. In order to provide appropriate recommendations regarding nutritional requirements and caloric needs, an accurate determination of energy requirements is necessary. By knowing an individual's EE, a coach, athletic performance staff or trainer can effectively determine training loads and volumes necessary for periodization and seasonal planning for a particular sport. The purpose of this study is to examine the accuracy of the BodyMedia Mini armband while measuring EE in female basketball players during various-intensity game-like conditions. This investigation required three testing sessions: an orientation session, and two randomized experimental trials. Trials included a maximal multistage 20-m shuttle run (Trial I) and 30-minute basketball skills session (Trial II). The independent variable for this investigation was EE estimated by the Mini armband. The dependent variable was EE determined by the Cosmed K4b2 indirect calorimetry (IC) method. EE assessed with the Mini and EE measured with the IC method was significantly correlated for both Trial I (r= 0.839) and Trial II (r= 0.833). EE calculated by the Mini was significantly underestimated in both Trial I (9.41 ± 26.1 total kcals) and Trial II (56.71 ± 14.1 total kcals). During Trial I the underestimation of EE increased with a rise in test level and intensity (p<.05). Due to the underestimation of EE by the Mini, the development of exercise specific algorithms to improve the estimation of EE during intermittent exercise in basketball players is warranted.

Exertional Observation in Adults Performing Intermittent Treadmill Walking and Running.

The present investigation examined the Adult OMNI Walk-Run Scale for use by an independent observer to rate an individual's perception of exertion during intermittent treadmill walking and running. Forty (22.4 ± 2.9 yrs) recreationally active males (n = 18) and females (n = 22) completed three 5-min intermittent bouts of treadmill exercise. The exercise bouts were a level walk (LW; 4.0 km·hr-1, 0% grade), hill walk (HW; 5.6 km·hr-1, 5% grade), and run (R; 8 km·hr-1, 2.5% grade). Each bout was separated by a 5-min recovery period. RPE responses were simultaneously estimated by an observer and self-estimated by the participant during each bout using the Adult OMNI Walk-Run Scale. Session RPE responses were simultaneously estimated by the same observer and self-estimated by the participant 5-min post-exercise session. Analysis of variance indicated no significant mean differences between observer RPE and participant RPE (p > 0.05) except for males during the running bout (p < 0.05). Additionally, there were no significant mean differences between the observer RPE and the participant RPE for the session ratings (p > 0.05). Finally, strong positive correlations were found between observer and participant RPE ranging from 0.79-0.84 for exercise bouts and moderate-strong positive correlations ranging from 0.58-0.64 for the exercise session. Results support the use of the OMNI RPE Scale in a direct observation procedure to estimate exertion in female and male young adults performing intermittent treadmill walking and running. This observation-based procedure provides the practitioner with an opportunity to independently evaluate the perceptual intensity of individuals involved in aerobic exercise.

Comparison of Affect and Cardiorespiratory Training Responses Between Structured Gym Activities and Traditional Aerobic Exercise in Children.

Physical activities (PA) that are pleasurable are likely to be repeated. Structured gym activities (SGA) are defined as dodging, chasing, and fleeing games. Traditional aerobic exercises (TAE) are defined as treadmill, cycle ergometer, and elliptical exercise. The purpose of this investigation was to compare affect and cardiorespiratory training responses between SGA and TAE in children. Thirty-two participants (9.3±0.2) were randomized to either the SGA or TAE group. Exercise training was seven weeks, with two sessions per week, for 35 minutes per session. Affect was measured by the (+5 (pleasurable) to -5 (displeasurable)) feelings scale. Affect was recorded at the mid-point and end of each exercise session. The 20-meter pacer test was used to assess cardiorespiratory fitness at baseline and post intervention. Affect responses and heart rates were averaged across all exercise sessions. The SGA group scored 2.77±0.2 affect units higher than the TAE group (p < 0.0001). The TAE group significantly increased cardiorespiratory fitness (baseline 47.8±3.8; post 49.1±3.1 ml·kg-1·min-1; p = 0.023) with no change in the SGA group (baseline 46.3±3.5; post 47.2±2.7 ml·kg-1·min-1; p = 0.127). SGA reported more positive affect, suggesting they experienced greater pleasure during the exercise sessions than the TAE participants. SGA activities promote more positive affect, and therefore may increase children's PA participation.

Energy Drinks Improve Five-Kilometer Running Performance in Recreational Endurance Runners.

Prins, PJ, Goss, FL, Nagle, EF, Beals, K, Robertson, RJ, Lovalekar, MT, and Welton, GL. Energy drinks improve five-kilometer running performance in recreational endurance runners. J Strength Cond Res 30(11): 2979-2990, 2016-The purpose of this study was to evaluate exercise performance time and related physiological and perceptual responses of recreational endurance runners after they had ingested a commercially available energy drink (Red Bull, Red Bull GmbH, Fuschl am See, Austria) containing caffeine, glucose, and taurine. Recreational endurance runners (n = 18; 13 men and 5 women; age: 20.39 ± 3.27 years; weight: 71.25 ± 17.17 kg; height: 178.00 ± 7.57 cm; V[Combining Dot Above]O2max: 55.94 ± 7.66 ml·kg·min) participated in a double-blind, crossover, repeated-measures study where they were randomized to supplement with 500 ml of the commercially available energy drink Red Bull and a noncaffeinated, sugar-free placebo (PLA) 60 minutes before completing a 5-km time trial on a treadmill, separated by 7 days. Heart rate, rating of perceived exertion (RPE) (RPE-Overall; RPE-Chest; RPE-Legs), and affect were recorded at rest, 1 hour before ingestion, at 5-minute intervals during the 5-km time trial, and immediately after exercise. Session RPE and session affect were obtained 5 minutes after completion of the 5-km time trial. The distance covered at each 5-minute interval during the 5-km time trial was recorded. Performance improved with the energy drink compared with placebo (Red Bull: 1,413.2 ± 169.7 vs. PLA: 1,443.6 ± 179.2 seconds; p = 0.016), but there were no differences in RPE, affect, session RPE, session affect, or the distance covered at 5-minute splits between the two 5-km time trials (p > 0.05). These results demonstrate that consuming a commercially available energy drink before exercise can improve 5-km performance. These results may have application for altering pre-exercise nutritional strategies in recreational runners.

Observation of OMNI scale of perceived exertion during fire suppression training.

Ratings of perceived exertion in 66 firefighters before, during, and immediately after performing 20 min. of fire suppression training were self-reported by the participants using the OMNI Walk-Run Scale and also recorded by a trained observer. The observer used the same definition of perceived exertion, instructions, and high and low anchoring procedures as the participants. Self-reported and observed ratings of perceived exertion did not differ before or during fire suppression training. Significant differences were noted between the self-reported and observed ratings immediately after fire suppression training. These findings support the use of direct observation to provide estimates of ratings of perceived exertion during fire suppression training.

Prediction of VO2 peak using OMNI Ratings of Perceived Exertion from a submaximal cycle exercise test.

The primary aim of this study was to develop statistical models to predict peak oxygen consumption (VO2 peak) using OMNI Ratings of Perceived Exertion measured during submaximal cycle ergometry. Male (M = 20.9 yr., SE = 0.4) and female (M = 21.6 yr., SE = 0.5) participants (N = 81) completed a load-incremented maximal cycle ergometer exercise test. Simultaneous multiple linear regression was used to develop separate VO2 peak statistical models using submaximal ratings of perceived exertion for the overall body, legs, and chest/breathing as predictor variables. VO2 peak (L·min(-1)) predicted for men and women from ratings of perceived exertion for the overall body (3.02 ± 0.06; 2.03 ± 0.04), legs (3.02 ± 0.06; 2.04 ± 0.04), and chest/breathing (3.02 ± 0.05; 2.03 ± 0.03) were similar to measured VO2 peak (3.02 ± 0.10; 2.03 ± 0.06, ps > .05). Statistical models based on submaximal OMNI Ratings of Perceived Exertion provide an easily administered and accurate method to predict VO2 peak.

Validation of the OMNI Scale of Thermal Sensations.

Concurrent and construct validation of the OMNI Scale of Thermal Sensations was examined in a sample of 16 adult men and 5 adult women. Concurrent validity was established by regressing OMNI ratings of thermal sensation against core and skin temperatures obtained during treadmill walking while wearing firefighter thermal-protective clothing in temperatures between 33 and 35 degrees C. Construct validity was established by regressing the OMNI scale against a construct-specific visual analogue scale. OMNI scale responses accounted for statistically significant variance in both skin temperature and core temperature (48% and 51%, respectively) and visual analogue scale responses (84%). Concurrent and construct validity were established for the OMNI Scale of Thermal Sensations in healthy adults performing treadmill walking while wearing fire fighter thermal protective clothing.

Validation of the OMNI RPE Seven Day Exertional Recall Questionnaire.

PURPOSE: The present study examined the validity of the Seven Day Recall Questionnaire among recreationally active men and women. METHOD: Initially, participants completed a level walk (2.5 mph [4.0 kph]), hill walk (3.5 mph [5.6 kph], 5% grade), and run (5.0 mph [8.0 kph], 2.5% grade). Seven days later, participants were given the Seven Day Recall Questionnaire and rated their perceived exertion associated with the exercise bouts. Participants then repeated the same exercise bouts as in Session 1, and the OMNI rating of perceived exertion (RPE) was estimated. RESULTS: Concurrent validity indicated that for both men and women, respectively, the RPE-Overall (r = .48, r = .70), RPE-Leg (r = .43, r = .66), and RPE-Chest (r = .47, r = .66) derived from the Seven Day Recall Questionnaire distributed as a function of oxygen consumption. RPE-Overall (r = .61, r = .76), RPE-Leg (r = .56, r = .72), and RPE-Chest (r = .61, r = .72) from the Seven Day Recall Questionnaire distributed as a function of heart rate. Convergent validity coefficients between the perceptual responses from the Seven Day Recall Questionnaire and the recall/criterion session were: level walk (r = .53-.87, r = .51-.80), hill walk (r = .65-.79, r = .56-.64), and run (r = .60-.68, r = .68-.78) for men and women, respectively. CONCLUSIONS: Concurrent and convergent evidence partially supports the utilization of the Seven Day Recall Questionnaire to recall the relative intensity of walking and running exercise sessions conducted 7 days prior.

Intensity selection and regulation using the OMNI scale of perceived exertion during intermittent exercise.

The purpose of this investigation was to determine if subjects can self-regulate exercise intensity during intermittent exercise by using ratings of perceived exertion. Thirty-one subjects completed an estimation trial maximal treadmill graded exercise test (GXT). Using the oxygen uptake and ratings of perceived exertion (RPE) from the GXT, target RPEs that corresponded to 50% and 70% of oxygen uptake reserve were determined. During the subsequent 20 min production trial, subjects titrated treadmill speed and grade to elicit the target RPEs that were presented in 2 counterbalanced orders (counterbalance order I (70%-50% of oxygen uptake reserve) or counterbalance order II (50%-70% of oxygen uptake reserve)). Heart rate (HR) and oxygen uptake were higher in the production trial compared with the estimation trial for counterbalance order I (p < 0.001) at an RPE that corresponded to 50% of oxygen uptake reserve. There was no difference in HR and oxygen uptake between the estimation and production trial for counterbalance order II (p < 0.05). HR was higher in the production trial compared with estimation trial for counterbalance order I (p < 0.05) at an RPE that corresponded to 70% of oxygen uptake reserve. There was no difference in HR between the estimation and production trials for counterbalance order II (p < 0.05). At an RPE that corresponded to 70% of oxygen uptake reserve, there was no difference in the oxygen uptake between the estimation and production trials (p < 0.05). A difference in HR (p < 0.05) and oxygen uptake (p < 0.05) between the 2 prescribed production trial intensities was indicated. The subjects were able to utilize RPE to self-regulate intensity during 20 min of exercise at varying intensity when beginning with the target RPE that corresponded to 50% of oxygen uptake reserve.

Session perceived exertion and affective responses to self-selected and imposed cycle exercise of the same intensity in young men.

Session perceived exertion (S-RPE) and session affective responses (S-AR) are post-exercise estimates of the global responses experienced during exercise. To compare S-RPE and S-AR to acute RPE (A-RPE) and acute AR (A-AR) during self-selected (SS) and imposed (IMP) exercise of the same workload. Thirty-two males (22.3 ± 2.2 years) performed two, 20-min cycle exercise trials. In the SS trial, subjects adjusted SS workload every 5 min. In the IMP trial, workload was automatically adjusted to the SS workload. Experimental (EXP, n = 16) subjects were unaware that workload was the same between the trials. Control (CON, n = 16) subjects were aware that both trials were of the same workload. A-RPE and A-AR were measured every 5 min using the OMNI Scale and Feeling Scale, respectively. Fifteen minutes following a cool-down, subjects rated S-RPE and S-AR. Session and exercise values were compared between trials and groups using ANOVA. No between-group differences were observed. There were no differences between the SS and IMP trials for S-RPE, A-RPE, S-AR and A-AR. For SS and IMP trials, S-RPE was greater than A-RPE (4.6 ± 1.5 vs. 3.9 ± 1.4; 4.3 ± 1.6 vs. 3.7 ± 1.4, respectively, p < 0.05). S-AR was greater than A-AR for the SS trial (1.9 ± 1.3 vs. 2.3 ± 1.5, p < 0.05), but not the IMP trial (1.9 ± 1.5 vs. 2.2 ± 1.4). A mismatch exists between the session and acute exercise values for RPE and AR during the SS cycle exercise in young males.

Just noticeable difference in perception of physical exertion during cycle exercise in young adult men and women.

The purpose of this investigation was to describe the just noticeable difference (JND) in perceived exertion during cycle exercise. Males (n = 20) and females (n = 26) (21.4 ± 3.1 year) performed load-incremented cycle exercise to peak intensity. At the end of each minute, subjects rated their overall-body perceived exertion using the OMNI (0-10) rating of perceived exertion (RPE) scale. Individual regression derived the power output (PO) corresponding to RPE 5. This PO served as the standard stimulus (SS). On a separate occasion, four 5-min cycling bouts were performed with 5 min rest between bouts. During bouts 1 and 3 subjects cycled at the SS. During bouts 2 and 4 subjects adjusted the resistance to achieve a level of exertion just noticeably above/below the SS. The difference in final 30-s oxygen consumption (VO2) and PO between each JND bout and the previous SS were the above (JND-A) and below (JND-B) perceived exertion JNDs. JND-A and JND-B were compared between genders and between subjects exhibiting lower versus higher ventilatory threshold (VT) and VO(2PEAK) within genders for VO2 (l · min(-1), %VO(2PEAK)) and PO (W, %SS). JND-B was significantly (P < 0.05) greater than JND-A for VO2 and PO, when expressed in absolute (l · min(-1), W) and relative units (%VO(2PEAK), %SS). Males exhibited greater JND values than females in absolute, but not relative, units. Subjects with lower and higher VT and VO(2)PEAK exhibited similar JND values. The JND can serve as an effective tool to measure perceptual acuity and to determine individual ability to self-regulate prescribed exercise intensities.

Evaluation of N95 respirator use with a surgical mask cover: effects on breathing resistance and inhaled carbon dioxide.

OBJECTIVE: For pandemic influenza outbreaks, the Institute of Medicine has recommended using a surgical mask cover (SM) over N95 filtering facepiece respirators (FFRs) among healthcare workers as one strategy to avoid surface contamination of the FFR which would extend its efficacy and reduce the threat of exhausting FFR supplies. The objective of this investigation was to measure breathing air quality and breathing resistance when using FFRs with US Food and Drug Administration-cleared SM and without SM. METHODS: Thirty National Institute for Occupational Safety and Health (NIOSH)-approved FFR models with and without SM were evaluated using the NIOSH Automated Breathing and Metabolic Simulator (ABMS) through six incremental work rates. RESULTS: Generally, concentrations of average inhaled CO(2) decreased and average inhaled O(2) increased with increasing O(2) consumption for FFR+SM and FFR-only. For most work rates, peak inhalation and exhalation pressures were statistically higher in FFR+SM as compared with FFR-only. The type of FFR and the presence of exhalation valves (EVs) had significant effects on average inhaled CO(2), average inhaled O(2), and breathing pressures. The evidence suggests that placement of an SM on one type of FFR improved inhaled breathing gas concentrations over the FFR without SM; the placement of an SM over an FFR+EV probably will prevent the EV from opening, regardless of activity intensity; and, at lower levels of energy expenditure, EVs in FFR do not open either with or without an SM. CONCLUSIONS: The differences in inhaled gas concentrations in FFR+SM and FFR-only were significant, especially at lower levels of energy expenditure. The orientation of the SM on the FFR may have a significant effect on the inhaled breathing quality and breathing resistance, although the measurable inhalation and exhalation pressures caused by SM over FFR for healthcare users probably will be imperceptible at lower activity levels.

Concurrent validity of an OMNI rating of perceived exertion scale for bench stepping exercise.

To develop and validate a modified OMNI rating of perceived exertion (RPE) scale for use during bench stepping exercise (OMNI-BS). Thirty women (age: 19.8 ± 1.8 years) undertook 2 experimental trials, separated by 7 days. Concurrent validity was established by examining the relation between physiological criterion variables, oxygen consumption (VO2), and heart rate (HR), with the concurrent variable, RPE from OMNI-BS, during 2 trials in which the intensity increased linearly (test 1) and intermittently (test 2). The first test consisted of 3-minute stages. Subjects stepped up and down on the bench at 120 b·min(-1). The test was terminated owing to subject fatigue. Exercise intensity increased as bench height increased every 3 minutes. The second test consisted of three 3-minute exercise bouts that reproduced exercise stage 1 (low intensity), stage 3 (moderate intensity), and stage 5 (high intensity) performed in the first test. The order of these 3 exercise bouts was counterbalanced. Intraclass correlation analysis from experimental trials indicated a strong positive association between RPE and VO2 (r = 0.96 and r = 0.95) and HR (r = 0.95 and r = 0.95). Concurrent validity for the OMNI-BS RPE scale was established for women performing bench stepping exercise.

Development of the physical activity index as a measure of total activity load and total kilocalorie expenditure during submaximal walking.

BACKGROUND: Pedometers are most accurate at measuring steps, less accurate at estimating distance, and even less accurate at estimating kilocalorie expenditure. The purpose of this investigation was to create a Physical Activity Index (PAI) using pedometer step counts and rating of perceived exertion (RPE) to enhance the ability to estimate kilocalorie expenditure during walking exercise. METHODS: Thirty-two females performed 3 counterbalanced walking bouts. During each bout, oxygen consumption, RPE, and step counts were measured. The PAI was calculated as the product of RPE and step count for each of the bouts. RESULTS: Concurrent validation of the PAI was established using VO2 as the criterion variable. A multiple regression analysis revealed a strong, positive relation between PAI score and VO2 (r=.91). Data were then used to develop a statistical model to estimate kcal expenditure using the PAI score as the predictor variable. CONCLUSION: The PAI was found to be an accurate method of estimating kcal expenditure and is a simple, unobtrusive and inexpensive tool which may be used in public health settings.

Development of a perceptual hyperthermia index to evaluate heat strain during treadmill exercise.

Fire suppression and rescue is a physiologically demanding occupation due to extreme external heat as well as the physical and thermal burden of the protective garments. These conditions challenge body temperature homeostasis and results in heat stress. Accurate field assessment of core temperature is complex and unreliable. The present investigation developed a perceptually based hyperthermia metric to measure physiologic exertional heat strain during treadmill exercise. Sixty-five (28.9 ± 6.8 years) female (n = 11) and male (n = 54) firefighters and non-firefighting volunteers participated in four related exertional heat stress investigations performing treadmill exercise in a heated room while wearing thermal protective clothing. Body core temperature, perceived exertion, and thermal sensation were assessed at baseline, 20-mins exercise, and at termination. Perceived exertion increased from baseline (0.24 ± 0.42) to termination (7.43 ± 1.86). Thermal sensation increased from baseline (1.78 ± 0.77) to termination (4.50 ± 0.68). Perceived exertion and thermal sensation were measured concurrently with body core temperature to develop a two-dimensional graphical representation of three exertional heat strain zones representative of a range of mean body core temperature responses such that low risk (green) incorporated 36.0-37.4°C, moderate risk (yellow) incorporated 37.5-37.9°C, and high risk (red) incorporated 38.0 to greater than 40.5°C. The perceptual hyperthermia index (PHI) may provide a quick and easy momentary assessment of the level of risk for exertional heat stress for firefighters engaged in fire suppression that may be beneficial in high-risk environments that threaten the lives of firefighters.

Effect of body mass index on affect at intensities spanning the ventilatory threshold.

The aim of this study was to compare acute affective responses at exercise intensities based on the ventilatory threshold between normal weight, overweight, and obese women. 66 sedentary women (22 in each Body Mass Index group) performed a maximal graded treadmill test to measure their maximal oxygen uptake and ventilatory thresholds. Affective valence was compared at intensities spanning the ventilatory threshold (below, at, and above threshold). Affective valence below ventilatory threshold did not differ among the Body Mass Index groups. The obese group had a lower affective response at ventilatory threshold and above ventilatory threshold than the normal weight and overweight groups; the latter two groups did not differ. The obese group had a lower affective response than the normal and overweight groups, which corresponds to a less pleasant experience. Exercise prescriptions for obese subjects targeting intensities below ventilatory threshold can provide a more pleasant experience and may facilitate exercise adherence.

Gender-based differences in substrate use during exercise at a self-selected pace.

The aim of this study was to investigate gender-based differences in substrate use during exercise at a self-selected pace. Seventeen men and 17 women performed a maximal exercise test and a 20-minute bout of self-paced treadmill walking to determine carbohydrate and fat oxidation rates. Gas exchange measurements were performed throughout the tests, and stoichiometric equations were used to calculate substrate oxidation rates. For each individual, a best-fit polynomial curve was constructed using fat oxidation rate (g·min(-1)) vs. exercise intensity (percentage of maximal oxygen uptake, % VO(2)max). Each individual curve was used to obtain the following variables: maximal fat oxidation (MFO), the peak rate of fat oxidation measured over the entire range of exercise intensities; fat(max), the exercise intensity at which the MFO was observed; and fat(max) zone, range of exercise intensities with fat oxidation rates within 10% of fat oxidation rates at fat(max). Although the MFO was similar between genders, fat(max) was lower in men than in women. Similarly, the "low" and "high" borders of the fat(max) zone were lower in men than in women. During exercise at a self-selected pace, carbohydrate oxidation rates were greater in men than in women, despite no gender-based differences in fat oxidation rates. However, fat oxidation contribution to total energy expenditure (EE) was greater in women than in men, despite no gender-based differences in the exercise intensity. In conclusion, although both genders self-selected a similar exercise intensity, the contribution of fat oxidation to EE is greater in women than in men. Interestingly, both genders self-selected an exercise intensity that falls within the fat(max) zone.