Mean Peak Heart Rate Research Articles

Heart Rate and Liking During "Kinect Boxing" Versus "Wii Boxing": The Potential for Enjoyable Vigorous Physical Activity Videogames.

Nintendo(®) (Kyoto, Japan) "Wii™ Sports Boxing" ("Wii Boxing") and Xbox(®) (Microsoft, Redmond, WA) "Kinect(®) Sports Boxing" ("Kinect Boxing") are both boxing simulation videogames that are available for two different active videogame (AVG) systems. Although these AVGs are similar, the style of gameplay required is different (i.e., upper body only versus total body movements) and may alter physical activity intensity and one's preference for playing one game over the other. AVGs that elicit the greatest physiologic challenge and are preferred by users should be identified in an effort to enhance the efficacy of physical activity interventions and programs that include AVGs. The mean heart rate (HRmean) and peak heart rate (HRpeak) for 27 adults (22.7±4.2 years old) were recorded during four 10-minute conditions: seated rest, treadmill walking at 3 miles/hour, "Wii Boxing," and "Kinect Boxing." Upon completion of all four conditions, participants indicated which condition they preferred, and HRmean and HRpeak were calculated as a percentage of age-predicted maximum heart rate to classify physical activity intensity for the three activity conditions (treadmill, "Wii Boxing," and "Kinect Boxing"). "Kinect Boxing" significantly (P<0.001) increased percentage HRmean (64.1±1.6 percent of age-predicted maximum) and percentage HRpeak (76.5±1.9 percent) above all other conditions: Wii HRmean, 53.0±1.2 percent; Wii HRpeak, 61.8±1.5 percent; treadmill HRmean, 52.4±1.2 percent; treadmill HRpeak, 55.2±2.2 percent. Percentage HRpeak for "Kinect Boxing" was great enough to be considered a vigorous-intensity physical activity. There was no difference (P=0.55) in percentage HRmean between "Wii Boxing" and treadmill walking. Participants also preferred "Kinect Boxing" (P<0.001; n=26) to all other conditions ("Wii Boxing," n=1; treadmill n=0). "Kinect Boxing" was the most preferred and the only condition that was physiologically challenging enough to be classified as a vigorous-intensity physical activity.

Long-term follow-up after aortic coarctation repair: The unsolved issue of exercise-induced hypertension

IntroductionDespite successful repair of aortic coarctation (AC), systemic hypertension (HTN) can persist in a significant percentage of patients. Exercise-induced HTN is also common in these patients, although its clinical significance is still unclear. In this study we aimed to assess the prevalence of exercise-induced HTN in adult patients with repaired AC. MethodsWe retrospectively reviewed the clinical records of patients aged >18 years with repaired AC followed at an adult congenital heart disease outpatient clinic in a tertiary care center. Demographic and clinical data including age at intervention, blood pressure (BP) at rest and on exercise, transthoracic echocardiogram (TTE) and treadmill exercise test results were evaluated. Exercise-induced HTN was defined as peak systolic BP ≥210 mmHg for men and ≥190 mmHg for women. ResultsWe analyzed 65 patients (40 [61.5%] male; mean age at follow-up 30±8 years). Median age at AC repair was 7 years (P25-P75: 4-20) and mean follow-up was 20±7 years. Only one patient had diabetes and 10 (15.4%) had dyslipidemia. The majority of patients had controlled BP at rest and only nine (18%) were under antihypertensive medication. Forty-nine patients performed a treadmill exercise test. The mean duration of exercise was 10.7±3.1 minutes and mean peak heart rate was 166±18 beats per minute. Eleven (22%) patients had a hypertensive response, among whom only three (33%) had uncontrolled BP at rest. In our study treatment with angiotensin-converting enzyme inhibitors (ACEI) (OR 4.0 [95% CI 1.9–18.1]) and the peak instantaneous gradient in the descending aorta by TTE (OR 8.2 [95% CI 1.8–37.0]) were predictors of a hypertensive response with exercise. Age at surgery and type of AC repair were not associated with a hypertensive response on exercise. ConclusionsIn this study we found a significant prevalence of exercise-induced HTN in adult patients after successful AC repair despite adequate BP control at rest. Exercise-induced HTN was significantly related to higher peak gradient in the descending aorta and treatment with ACEI. These results highlight the complexity of the adult AC population and show that, even after a good surgical result, several patients remain at high cardiovascular risk and require long-term follow-up.

Long-term follow-up after aortic coarctation repair: The unsolved issue of exercise-induced hypertension

IntroductionDespite successful repair of aortic coarctation (AC), systemic hypertension (HTN) can persist in a significant percentage of patients. Exercise-induced HTN is also common in these patients, although its clinical significance is still unclear. In this study we aimed to assess the prevalence of exercise-induced HTN in adult patients with repaired AC. MethodsWe retrospectively reviewed the clinical records of patients aged >18 years with repaired AC followed at an adult congenital heart disease outpatient clinic in a tertiary care center. Demographic and clinical data including age at intervention, blood pressure (BP) at rest and on exercise, transthoracic echocardiogram (TTE) and treadmill exercise test results were evaluated. Exercise-induced HTN was defined as peak systolic BP ≥210 mmHg for men and ≥190 mmHg for women. ResultsWe analyzed 65 patients (40 [61.5%] male; mean age at follow-up 30±8 years). Median age at AC repair was 7 years (P25-P75: 4-20) and mean follow-up was 20±7 years. Only one patient had diabetes and 10 (15.4%) had dyslipidemia. The majority of patients had controlled BP at rest and only nine (18%) were under antihypertensive medication. Forty-nine patients performed a treadmill exercise test. The mean duration of exercise was 10.7±3.1 minutes and mean peak heart rate was 166±18 beats per minute. Eleven (22%) patients had a hypertensive response, among whom only three (33%) had uncontrolled BP at rest. In our study treatment with angiotensin-converting enzyme inhibitors (ACEI) (OR 4.0 [95% CI 1.9–18.1]) and the peak instantaneous gradient in the descending aorta by TTE (OR 8.2 [95% CI 1.8–37.0]) were predictors of a hypertensive response with exercise. Age at surgery and type of AC repair were not associated with a hypertensive response on exercise. ConclusionsIn this study we found a significant prevalence of exercise-induced HTN in adult patients after successful AC repair despite adequate BP control at rest. Exercise-induced HTN was significantly related to higher peak gradient in the descending aorta and treatment with ACEI. These results highlight the complexity of the adult AC population and show that, even after a good surgical result, several patients remain at high cardiovascular risk and require long-term follow-up.

Heart rate changes during electroconvulsive therapy

BackgroundThis observational study documented heart rate over the entire course of electrically induced seizures and aimed to evaluate the effects of stimulus electrode placement, patients' age, stimulus dose, and additional predictors.MethodIn 119 consecutive patients with 64 right unilateral (RUL) and 55 bifrontal (BF) electroconvulsive treatments, heart rate graphs based on beat-to-beat measurements were plotted up to durations of 130 s.ResultsIn RUL stimulation, the initial drop in heart rate lasted for 12.5 ± 2.6 s (mean ± standard deviation). This depended on stimulus train duration, age, and baseline heart rate. In seizures induced with BF electrode placement, a sympathetic response was observed within the first few seconds of the stimulation phase (median 3.5 s). This was also the case with subconvulsive stimulations. The mean peak heart rate in all 119 treatments amounted to 135 ± 20 bpm and depended on baseline heart rate and seizure duration; electrode placement, charge dose, and age were insignificant in regression analysis. A marked decline in heart rate in connection with seizure cessation occurred in 71% of treatments.ConclusionsA significant independent effect of stimulus electrode positioning on cardiac action was evident only in the initial phase of the seizures. Electrical stimulation rather than the seizure causes the initial heart rate increase in BF treatments. The data reveal no rationale for setting the stimulus doses as a function of intraictal peak heart rates (‘benchmark method’). The marked decline in heart rate at the end of most seizures is probably mediated by a baroreceptor reflex.

Validity of an Exercise Test Based on Habitual Gait Speed in Mobility-Limited Older Adults

Li X, Forman DE, Kiely DK, LaRose S, Hirschberg R, Frontera WR, Bean JF. Validity of an exercise test based on habitual gait speed in mobility-limited older adults. ObjectiveTo evaluate whether a customized exercise tolerance testing (ETT) protocol based on an individual's habitual gait speed (HGS) on level ground would be a valid mode of exercise testing older adults. Although ETT provides a useful means to risk-stratify adults, age-related declines in gait speed paradoxically limit the utility of standard ETT protocols for evaluating older adults. A customized ETT protocol may be a useful alternative to these standard methods, and this study hypothesized that this alternative approach would be valid. DesignWe performed a cross-sectional analysis of baseline data from a randomized controlled trial of older adults with observed mobility problems. Screening was performed using a treadmill-based ETT protocol customized for each individual's HGS. We determined the content validity by assessing the results of the ETTs, and we evaluated the construct validity of treadmill time in relation to the Physical Activity Scale for the Elderly (PASE) and the Late Life Function and Disability Instrument (LLFDI). SettingOutpatient rehabilitation center. ParticipantsCommunity-dwelling, mobility-limited older adults (N=141). InterventionsNot applicable. Main Outcome MeasuresCardiac instability, ETT duration, peak heart rate, peak systolic blood pressure, PASE, and LLFDI. ResultsAcute cardiac instability was identified in 4 of the participants who underwent ETT. The remaining participants (n=137, 68% female; mean age, 75.3y) were included in the subsequent analyses. Mean exercise duration was 9.39 minutes, with no significant differences in durations being observed after evaluating among tertiles by HGS status. Mean peak heart rate and mean peak systolic blood pressure were 126.6 beats/min and 175.0mmHg, respectively. Within separate multivariate models, ETT duration in each of the 3 gait speed groups was significantly associated (P<.05) with PASE and LLFDI. ConclusionsMobility-limited older adults can complete this customized ETT protocol, allowing for the identification of acute cardiac instability and the achievement of optimal exercise parameters.

A comparison of a portable blood lactate analyser and laboratory plasma analysis of blood samples from exercised horses

Quick, simple methods for blood lactate analysis could be helpful in evaluating xercise response in the field, but methods validated for analysis of blood collected after high intensity exercise in horses are scarce. The aim of the present study was to compare the results obtained using a commercial, portable blood lactate analyser with those from laboratory plasma analysis of blood samples from horses performing intensive exercise. Venous blood samples were collected from 220 horses within 5 min of performing exercise at a mean peak heart rate of 222 ±9 beats/min. The samples were kept chilled and analysed using portable analyser within 10 min of collection. Samples were also centrifuged and the plasma frozen (-20 °C) until analysed using an enzymatic and spectrophotometric laboratory lactate analysis. There was a significant (P&lt;0.05) correlation (R=0.94) between the methods at portable analyser values &lt;12.0 mmol/l, but at higher values there was no correlation. There was a significant effect of method (P&lt;0.0001) and portable analyser values were 21% lower than plasma lactate concentrations in the range 2.0-12.0 mmol/l. It is concluded that the portable analysis correlated well to a laboratory plasma analysis at portable analyser values &lt;12.0 mmol/l and that the portable analyser appears to be a safe method for lactate analysis during training conditions, when very high lactate concentrations are not expected. However, users should be aware that the results underestimate the corresponding plasma values by approximately 20%.

Heart Rate Response to Exercise Stress Testing in Asymptomatic Women

The definition of a normal heart rate (HR) response to exercise stress testing in women is poorly understood, given that most studies describing a normative response were predominately based on male data. Measures of an attenuated HR response (chronotropic incompetence) and age-predicted HR have not been validated in asymptomatic women. We investigated the association between HR response to exercise testing and age with prognosis in 5437 asymptomatic women. Participants underwent a symptom-limited maximal stress test in 1992. HR reserve (change in HR from rest to peak), chronotropic index, and age-predicted peak HR were calculated. Deaths were identified to December 31, 2008. Mean age at baseline was 52+/-11 years, with 549 deaths (10%) over 15.9+/-2.2 years. Mean peak HR was inversely associated with age; mean peak HR=206-0.88(age). After adjusting for exercise capacity and traditional cardiac risk factors, risk of death was reduced by 3% for every 1-beat-per-minute increase in peak HR, and by 2% for every 1-beat-per-minute increase in HR reserve (P<0.001). Inability to achieve 85% age-predicted HR was not an independent predictor of mortality, but being >/=1 SD below the mean predicted HR or a chronotropic index <0.80 based on the prediction model established by this cohort were independent predictors of mortality (P<0.001 and P=0.023, respectively). Chronotropic incompetence is associated with an increased risk of death in asymptomatic women; however, the traditional male-based calculation overestimates the maximum HR for age in women. Sex-specific parameters of physiological HR response to exercise should be incorporated into clinical practice.

Heart rates of horses during competitive dressage

An understanding of the physiological and metabolic demands of competition is essential for the development of training regimens that elicit adaptations appropriate for the sport being participated in. Despite the fact that dressage is a major sport and one of only three equestrian Olympic disciplines, to date there appear to be no studies that have described the heart rate of horses performing competitive dressage in any detail. The present study was therefore undertaken to describe the physiological demands of dressage competition. Thirty-five horses competing in a total of 50 dressage tests, 36 of which were at British dressage (BD) elementary level and 14 at BD medium level, were studied. The horses studied were predominantly Warmblood or Thoroughbred cross geldings with an age range from 6 to 17 (mean ± SD age of 10.0 ± 2.5 years). The average durations of warm-up for all horses competing were 31.3 ± 15.4 min at elementary level (n = 36) and 31.4 ± 10.0 min at medium level (n = 14; P&gt;0.05). The mean and mean peak heart rates for horses warming up for elementary level were 91 ± 13 and 146 ± 35 bpm (beats min− 1), respectively, and were not different to that for horses warming up for medium level (mean 91 ± 10 bpm; peak: 144 ± 32 bpm; P&gt;0.05). The mean and mean peak heart rates for all horses while competing at elementary level (n = 36) were 102 ± 13 and 132 ± 20 bpm, respectively, and 107 ± 8 and 132 ± 10 bpm, respectively, for medium level (n = 14), and were not significantly different (P&gt;0.05). Mean heart rates during competition were significantly higher compared with that during warm-up for both elementary and medium levels (P &lt; 0.001). Mean heart rate during competition (elementary and medium data combined) was significantly correlated with mean heart rate during warm-up (r2 = 0.503; n = 50; P &lt; 0.001). There was no association between heart rate, warm-up duration and score or placing. These observations suggest that competitive dressage at BD elementary and medium levels is only moderately aerobically demanding.

The multi-stage fitness test as a predictor of endurance fitness in wheelchair athletes

The aims of this study were two-fold: (1) to consider the criterion-related validity of the multi-stage fitness test (MSFT) by comparing the predicted maximal oxygen uptake ([Vdot]O2max) and distance travelled with peak oxygen uptake ([Vdot]O2peak) measured using a wheelchair ergometer (n = 24); and (2) to assess the reliability of the MSFT in a sub-sample of wheelchair athletes (n = 10) measured on two occasions. Twenty-four trained male wheelchair basketball players (mean age 29 years, s = 6) took part in the study. All participants performed a continuous incremental wheelchair ergometer test to volitional exhaustion to determine [Vdot]O2peak, and the MSFT on an indoor wooden basketball court. Mean ergometer [Vdot]O2peak was 2.66 litres · min−1 (s = 0.49) and peak heart rate was 188 beats · min−1 (s = 10). The group mean MSFT distance travelled was 2056 m (s = 272) and mean peak heart rate was 186 beats · min−1 (s = 11). Low to moderate correlations (ρ = 0.39 to 0.58; 95% confidence interval [CI]: −0.02 to 0.69 and 0.23 to 0.80) were found between distance travelled in the MSFT and different expressions of wheelchair ergometer [Vdot]O2peak. There was a mean bias of −1.9 beats · min−1 (95% CI: −5.9 to 2.0) and standard error of measurement of 6.6 beats · min−1 (95% CI: 5.4 to 8.8) between the ergometer and MSFT peak heart rates. A similar comparison of ergometer and predicted MSFT [Vdot]O2peak values revealed a large mean systematic bias of 15.3 ml · kg−1 · min−1 (95% CI: 13.2 to 17.4) and standard error of measurement of 3.5 ml · kg−1 · min−1 (95% CI: 2.8 to 4.6). Small standard errors of measurement for MSFT distance travelled (86 m; 95% CI: 59 to 157) and MSFT peak heart rate (2.4 beats · min−1; 95% CI: 1.7 to 4.5) suggest that these variables can be measured reliably. The results suggest that the multi-stage fitness test provides reliable data with this population, but does not fully reflect the aerobic capacity of wheelchair athletes directly.

Efficacy and systemic side‐effects of topical 0.5% timolol aqueous solution and 0.1% timolol hydrogel

The objective of this randomized, double-blind, controlled crossover trial was to compare 0.1% timolol hydrogel formulation eyedrops with 0.5% timolol aqueous solution in terms of systemic effects, hypotensive efficacy and pharmacodynamics. Twenty-four healthy subjects underwent careful ocular, cardiovascular and pulmonary function evaluation before and after 2 weeks of topical treatment with 0.1% timolol hydrogel or 0.5% aqueous timolol maleate. Intraocular pressure (IOP), heart rate, blood pressure, forced expiratory volume and plasma levels of timolol were measured. There was a statistically significant difference in the systemic absorption of timolol between these two ophthalmic timolol solutions. The peak concentration and mean area under the plasma drug concentration-time curve (AUC) were about 10-fold higher after 0.5% timolol aqueous solution. The mean peak heart rate during exercise was reduced by 19 bpm (SD 6.4 bpm) after 0.5% timolol aqueous solution and by only 4.6 bpm (SD 3.8 bpm) after 0.1% timolol hydrogel (p < 0.0001). There was no difference between the two formulations in efficacy in reducing IOP. No differences between treatments were found in respect of pulmonary function. The lower timolol concentration in the hydrogel vehicle and its better bioavailability resulted in reduced systemic absorption and side-effects without loss of efficacy.

A novel method for the performance of isometric exercise in the home

There is a paucity of research on devices suitable for home-based isometric exercise. Our aim was to compare cardiovascular responses to isometric exercise using novel and established methods. Ten individuals (age 34.0 ± 8.5 years, mass 68.2 ± 10.4 kg, height 1.72 ± 0.09 m; mean ± s) performed three different isometric exercise protocols with 48 h between each. Each protocol involved four repeated exercise bouts of 2 min at 30% maximum voluntary contraction force using alternate legs (transducer), alternate arms (transducer), or alternate arms (novel device). Systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and heart rate were measured every 30 s. The highest (peak) values during each 2 min bout of exercise were recorded (peak systolic blood pressure, peak diastolic blood pressure, peak mean arterial blood pressure and peak heart rate). At the end of each 2 min exercise bout, the participants rated their perceived discomfort using Borg's CR-10 scale. There was a statistically significant difference in peak systolic blood pressure between isometric arm flexion using the force transducer and the novel device [158.1 ± 10.8 vs. 149.1 ± 13.9 mmHg (mean ± s); P = 0.02]. Further analysis showed that peak systolic blood pressure was on average 9 mmHg higher using the force transducer with limits of agreement of – 15.97 to 33.97 mmHg. Analysis of the peak diastolic blood pressure, peak mean arterial blood pressure, peak heart rate and CR-10 data revealed no statistically significant differences between the three protocols. These results suggest that this novel, home-based method elicited similar cardiovascular responses during isometric exercise to those of established laboratory-based methods. However, the lower peak systolic blood pressure using the modified scales warrants further investigation before this method is used widely in the home.

Effects of stage duration in incremental running tests on physiological variables.

To study the effect of stage duration on some physiological variables in an incremental running test, 8 well-trained runners underwent 3 running tests, with stage durations of 1, 3 and 6 min. To study maximal lactate steady state (maxLASS) and its corresponding speed, every subject underwent a 4th test with three 15-min stages at three speeds, based on the running speed at 4 mmol/l blood lactate (V4) in the 6 min per stage protocol. The first load in the 15 min per stage test was V4 - 0.5 km/h, the second at V4, and the third V4 + 0.5 km/h. To compare the maxLASS speed with outdoor performance, the subjects also ran 5 km at this speed on an outdoor track. Mean maximal running speed (V (max)) in the incremental test was significantly lower in the 6-min (15.1 km/h) and 3-min stage protocol (17.1 km/h), compared with the 1-min stage protocol (18.3 km/h). Mean peak VO (2) and mean peak heart rate were not different between the protocols with different stage duration. The mean V4 was significantly lower in the 6 min per stage protocol compared with the 3 min per stage protocol (12.9 vs. 14.4 km/h). Mean ventilatory threshold was not different between the 1, 3 and 6 min per stage protocols. No threshold behaviour was found in respiratory rate. MaxLASS can be estimated from V4 in the 6 min per stage protocol, and verified by three 15-min intensities being V4 - 0.5 km/h, at V4, and V4 + 0.5 km/h. The mean blood lactate concentration at the maxLASS speed was not different between treadmill running and outdoor running on a track. In conclusion, for measuring peak values of physiological variables in an incremental running test, the duration per stage is of less importance, however, when measuring blood lactate concentration as a function of running speed, the duration per stage should be at least 6 min.

Acute hemodynamic effects of abdominal exercise with and without breath holding

Finnoff JT, Smith J, Low PA, Dahm DL, Harrington SP. Acute hemodynamic effects of abdominal exercise with and without breath holding. Arch Phys Med Rehabil 2003;84:1017-22. Objectives:To compare the magnitudes of change in heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure, and rate-pressure product (RPP) during 3 abdominal exercises: straight partial sit-up (SPSU), oblique partial sit-up (OPSU), and the AbSculptor® sit-up; and to examine the effect of breath holding on these parameters. Design:Prospective, repeated measures. Setting:Autonomic research laboratory in a major medical center. Participants:Fourteen normal male and female volunteers (age range, 24–37y; mean, 30.4y). Interventions:Hemodynamic parameters were recorded during each abdominal exercise performed with and without breath holding. Mean peak values were calculated for 1 minute before exercise, during exercise, and for 10 minutes after exercise. Main Outcome Measures:Statistical analysis examined for differences in the hemodynamic changes among the 3 exercises under both conditions (with and without breath holding). Results:Heart rate, SBP, DBP, mean blood pressure, and RPP increased during all 3 exercises. The mean peak heart rate and RPP increases were greater for the OPSU than the AbSculptor (heart-rate increase, 21.1±6.6bpm vs 17.6±5.7bpm, P=.03; RPP increase, 36.9±15.5bpm·mmHg vs 29.4±10.1bpm·mmHg, P=.05). For all 3 exercises, breath holding significantly increased the hemodynamic parameter elevations during exercise, with the exception of heart rate (SBP, P<.001; DBP, P<.001; mean blood pressure, P<.001; RPP, P=.02). Quantitatively, breath holding during the OPSU resulted in the largest exercise-associated increases in heart rate (21.0±8.1bpm), mean blood pressure (22.2±16.4mmHg), and RPP (44.9±22.3bpm·mmHg). Postexercise, all hemodynamic parameters generally returned to baseline within several minutes. Conclusion:When performing the OPSU, SPSU, or the AbSculptor exercises as used in this investigation, normal individuals exercising at low intensities may experience peak heart rate and mean blood pressure increases of 30bpm and 50mmHg, respectively. Voluntary breath holding significantly increased the peak blood pressure elevations and RPP for all 3 exercises, but particularly for the OPSU.

Exercise performance after the arterial switch operation for d-transposition of the great arteries

Early- and intermediate-term results of the arterial switch operation for D-transposition of the great arteries (D-TGA) are encouraging. However, questions remain about the long-term outcome for these patients, especially with regard to exercise performance. Preliminary studies have demonstrated normal endurance time on treadmills. However, data regarding aerobic capacity and cardiopulmonary function are lacking. We report the cardiopulmonary performance of 22 school-age patients with D-TGA who underwent the arterial switch operation. Outcome variables included maximal oxygen consumption (VO2), maximal cardiac index, and peak heart rate. Patient and procedure-related variables were assessed for their association with outcome variables using linear and logistic regression. The mean values of maximal VO2 (113 ± 19% predicted) and maximal cardiac index (96 ± 18% predicted) were within normal limits for the pediatric population. Although the mean peak heart rate for the entire group (184 ± 14 beats/min) was within normal limits, there were 7 subjects (32%) with chronotropic impairment. Significant ST-segment depression was seen in 2 subjects (9%). In regression analysis, surgery subsequent to the arterial switch was associated with lower maximal cardiac index (p = 0.01). Other variables were not significantly associated with maximal VO2, maximal cardiac index, and peak heart rate. In particular, chronotropic impairment was not significantly associated with maximal VO2 or maximal cardiac index. These findings demonstrate that cardiopulmonary performance during exercise is excellent after the arterial switch operation. The finding of ST-segment depression in some subjects supports the role of formal exercise testing in those patients participating in vigorous athletic activities.

Exercise testing: Improving performance with a ramped Bruce protocol

Background The standard Bruce protocol was compared with a ramped Bruce protocol in stress testing of a general population of patients. Methods We examined hemodynamic responses, test duration, and patient comfort with each exercise protocol. Twenty-three patients completed the study, 14 men and 9 women with a mean age of 51 ± 12 years. Each patient completed the 2 treadmill protocols in a random manner. Results Mean peak heart rate, systolic blood pressure, and rating of perceived exertion according to the revised Borg scale were equivalent in both protocols, measuring 157 ± 15 beats/min, 170 ± 22 mm Hg, and 8 ± 1 for the Bruce and 158 ± 17 beats/min, 175 ± 20 mm Hg, and 8 ± 1 for the ramp protocol ( P = NS). Duration of test and metabolic equivalents (METs) were greater with the ramp than with the Bruce protocol. For the Bruce duration and METs were 8:25 ± 3:00 min and 9.6 ± 3.1, and for the ramp 10:01 ± 2:32 min and 11.4 ± 2.7 ( P < .0001 for both). Subjective rating of difficulty was assessed on a scale of 1 to 5, 1 being the most difficult and 5 being the easiest. Rating for the Bruce protocol was 2.5 ± 0.9 and for the ramp 4.1 ± 0.9 ( P < .0001). Conclusion We propose that a ramped modification of the Bruce protocol achieves equivalent hemodynamic goals but with better duration. Patients preferred the ramp with respect to comfort, and exercise data can be correlated easily with standard protocols. (Am Heart J 1999;138:1033-7.)

Topical lidocaine-prilocaine versus lidocaine for neonatal circumcision: a randomized controlled trial

Objective: To evaluate epicutaneous application of 5% lidocaine-prilocaine and 30% lidocaine cream anesthetics for neonatal circumcision. Methods: The efficacy of 5% lidocaine-prilocaine and 30% lidocaine creams was compared in a randomized, double-blind, placebo-controlled trial. Sixty-one neonates were randomly assigned to one of three groups: 5% prilocaine-lidocaine ( n = 20), 30% lidocaine ( n = 20), and a control group that received an acid-mantle cream ( n = 21). Heart rate, oxygen saturation, and crying time were monitored before, during, and after circumcision. Blood pressure was measured before and after circumcision. Results: Mean peak heart rates for the 5% lidocaine-prilocaine, 30% lidocaine, and control groups (± standard deviation) were 146 ± 16, 157 ± 10, and 164 ± 16 beats per minute, respectively. During four of six active phases of circumcision, the 5% lidocaine-prilocaine group suppressed significant increases in heart rate better than 30% lidocaine, which was more effective than control (dorsal clamp, P < .001; bell clamp on, P = .001; tightening, P = .001; bell clamp off, P < .001). During tightening of the bell clamp, significantly less crying was seen in the 5% lidocaine-prilocaine group (13 ± 12 seconds) compared with 30% lidocaine (24 ± 14 seconds) and controls (38 ± 27 seconds) ( P < .001). The group that received 5% lidocaine-prilocaine also had no significant increase in systolic ( t = 1.6, P = .12) or diastolic ( t = 1.9, P = .067, respectively) blood pressure, unlike the group receiving 30% lidocaine ( t = 4.8, P = .001 and t = 2.9, P = .009, respectively) and the placebo group ( t = 2.5, P = .023 and t = 2.3, P = .032). There were no significant differences in oxygen saturation (α = .05, power 0.79). Conclusion: Epicutaneous 5% lidocaine-prilocaine was more effective than 30% lidocaine for neonatal circumcision, better reducing neonatal stress indicators. Lidocaine-prilocaine significantly shortened crying time during one of the most painful phases of circumcision. Both topical anesthetics were more effective than placebo in attenuating the behavioral and physiologic indicators of neonatal pain.

Detection of atrial fibrillation during sinus tachycardia induced by exercise in patients with implantable atrial defibrillators.

Accurate detection of atrial fibrillation (AF) is essential for appropriate operation of an implantable atrial defibrillator (IAD). However, during episodes of sinus tachycardia, distinction between AF and sinus rhythm (SR) using the "quiet interval" and "baseline crossing" analysis in the detection algorithm of the IAD may be difficult. The efficacy of this AF detection algorithm was tested in five patients implanted with an IAD (METRIX, Model 3000 or 3020, InControl Inc.) during treadmill exercise testing. The IADs were programmed to Monitor Mode with a wake up cycle of 1 minute for AF detection using the device nominal parameters or modified parameters, and to mark rhythms appropriate for shock delivery. A mean peak heart rate of 137 +/- 26 beats/min was reached during maximum exercise, and one patient developed transient AF. Seventy-eight (75 in SR, 3 in AF) and 91 (89 in SR, 2 in AF) runs of AF detection were performed using the nominal and modified parameters, respectively. The IAD detected AF and SR accurately, except for one episode of false-positive AF detection during sinus tachycardia at the nominal settings, but inappropriate shocks were prevented by minimum RR interval criteria that limited discharge at high heart rate. These results indicate that the AF detection algorithm in the IAD may become more vulnerable to false-positive AF detection during sinus tachycardia, which were avoided by reprogramming the Quiet Interval and minimum RR interval criteria for AF detection. Exercise testing appeared useful to program optimal settings of the IAD in preparation for daily activities.

The effects of housing on heart rate of gestating sows during specific behaviours

The heart rates of 21 sows in three different dry sow housing systems were measured during feeding, drinking, rooting and lying with eyes open. Measurements were made on sows kept in: (1) a large group of 37 with an electronic sow feeder ( n = 7); (2) small groups of five, with individual feeders ( n = 7); (3) individual stalls ( n = 7). For all three systems, heart rate was highest during feeding and lowest during lying, with rooting and drinking intermediate. When comparing between systems, stall-housed sows had significantly higher basal heart rates (54.1 b.p.m.) and average feeding heart rates (118.5 b.p.m.) than sows from large-group (45.9 b.p.m. and 105.9 b.p.m.) and small-group housing systems (46.7 b.p.m. and 102.5 b.p.m.). The variability of heart rate during feeding and the difference between average feeding heart rate and basal heart rate was also highest in stall-housed sows. Sows housed in the small group had higher mean peak heart rates during feeding than sows housed in the large group with stall-housed sows intermediate. Long-term confinement in stalls may induce a greater sympathetic nervous response to important stimuli such as feeding. However, a feeding environment in which there can be contact between sows results in higher mean peak feeding heart rates and heart rate variability probably due to short-term adrenal responses to agonistic interactions.

Effect of maximal arm exercise on skin blood flux in the paralyzed lower limbs in persons with spinal cord injury.

The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC) were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subject's mean peak oxygen uptake and peak heart rate was 1.41 +/- 0.22 l.min-1 and 171.6 +/- 19.2 beats.min-1, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest. These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE.

Thermoregulatory response to wearing encapsulated protective clothing during simulated work in various thermal environments.

This investigation assessed the thermoregulatory impact of performing simulated tasks normally encountered during chemical accident clean-up while wearing chemical protection clothing under various representative thermal loads. A Drager 500 (D) suit was worn with a self-contained breathing apparatus (SCBA) external to the suit, while both a Trelleborg Trellchem Super Extra (T) and a James North MZ500 (J) suit required the SCBA to be worn inside the suit. The D suit was unventilated, while the T and S suits were ventilated with the subject's exhaled air. The T suit also was ventilated via a 2 L/min flow of air from the SCBA. Subjects were six firefighters. Each simulation lasted for 30 minutes and involved tasks such as drum rolling, drum carrying, walking, and hose dragging. The trials were conducted at 11.3, 17.1, and 23.8 degrees C WBGT. The overall mean peak heart rate was 128.1 +/- 2.80 breaths/min and was elicited while performing lifting tasks. Nonsignificant differences (p > 0.05) were observed for both the average heart rate and sweat rate. Mean skin temperature, mean body temperature, and temperature within the suit cavity were significantly higher when wearing the D suit compared to wearing T or J suits; differences between the T and J suits were nonsignificant. Suit type did not significantly affect rectal temperature, which also failed to exceed the American Council of Governmental Industrial Hygienists' (ACGIH) standard of 38.0 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)