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Biomedical subjects

S J Petruzzello

Publications and source records attributed to S J Petruzzello.

At least 19 recordsLinked to original sources
PubMed2005

Selected hormonal and immunological responses to strenuous live-fire firefighting drills.

This study investigated the effects of strenuous live-fire firefighting drills and a 90 min recovery period on selected hormonal, immunological and psychological variables. Apparently healthy, male, professional firefighters (n = 11) performed three trials of standardized firefighting tasks in a live-fire training structure. There was significant leukocytosis immediately post firefighting activity that persisted following recovery, although there was a variable response among the leukocyte subsets. Most notable was the decrease in number and percentage of lymphocytes following 90 min of recovery. Plasma levels of ACTH and cortisol were significantly elevated post firefighting activity and cortisol remained elevated following 90 min of recovery. Elevated cortisol immediately following activity was related to reduced feelings of energy. These data demonstrate the magnitude of the physiological and psychological disruption following strenuous firefighting activity and suggest that immune function may be altered following such activity. This is a finding that may have practical consequences for this group of first responders.

Adrenocorticotropic Hormone↗
PubMed2001

Effect of strenuous live-fire drills on cardiovascular and psychological responses of recruit firefighters.

The study examined the effects of repeated strenuous live-fire drills on cardiovascular and psychological responses of male recruit firefighters (n = 7). Participants performed three trials of a standardized set of tasks while inside a training structure containing several live fires. Measurements of heart rate, aortic blood flow, perceived exertion, respiratory and thermal distress, reaction time, and error rate were obtained before testing, after each trial and during recovery. Heart rate increased significantly during each of the trials, reaching age-predicted maximal values. Stroke volume was significantly lower after trial 3 versus trial 1 and prevalues. Perceived exertion, respiratory distress, and thermal distress all increased, indicating greater stress following firefighting activities. Reaction time and error rate did not change significantly, but there was a tendency for more errors following trials 2 and 3 versus trial 1. The training drills resulted in considerable physiological and psychological strain, which has the potential to impair cognitive function. Firefighters are encouraged to take all possible steps to mitigate the extent of the cardiovascular strain.

Cardiovascular System↗
PubMed2001

Regional brain activation as a biological marker of affective responsivity to acute exercise: influence of fitness.

Previous research has shown that regional brain activation, assessed via frontal electroencephalographic (EEG) asymmetry, predicts affective responsivity to aerobic exercise. To replicate and extend this work, in the present study we examined whether resting brain activation was associated with affective responses to an acute bout of aerobic exercise and the extent to which aerobic fitness mediated this relationship. Participants (high-fit, n = 22; low/moderate-fit, n = 45) ran on a treadmill for 30 min at 75% VO2max. EEG and affect were assessed pre- and 0-, 10-, 20-, and 30-min postexercise. Resting EEG asymmetry predicted positive affect (as measured by the energetic arousal subscale of the Activation Deactivation Adjective Check List) postexercise. Furthermore, resting frontal EEG asymmetry predicted affect only in the high-fit group, suggesting the effect might be mediated by some factor related to fitness. It was also shown that subjects with relatively greater left frontal activation had significantly more energy (i.e., activated pleasant affect) following exercise than subjects with relatively greater right frontal activation. In conclusion, aerobic fitness influenced the relationship between resting frontal asymmetry and exercise-related affective responsivity.

Adult↗
PubMed2000

Walking in (affective) circles: can short walks enhance affect?

Recent physical activity recommendations call for activities that are of moderate intensity and can be performed intermittently during the day, such as walking. These proclamations were based partly on the assumption that moderate activities are generally more enjoyable than physically demanding ones, and they are, therefore, also more likely to be continued over the long haul. However, little is actually known about the affective outcomes of short bouts of walking and extant findings are equivocal. Four experimental studies examined the affective responses associated with short (10- to 15-min) bouts of walking using a dimensional conceptual model of affect, namely, the circumplex. Results consistently showed that walking was associated with shifts toward increased activation and more positive affective valence. Recovery from walking for 10-15 min was associated with a return toward calmness and relaxation. This pattern, was robust across different self-report measures of the circumplex affective dimensions, across ecological settings (field and laboratory), across time, and across samples.

Adult↗
PubMed1999

Acute aerobic exercise and affect: current status, problems and prospects regarding dose-response.

One of the assumptions underlying recent physical activity recommendations is that lower doses of activity (i.e. intensity and duration) are more enjoyable for the average person, thus leading to higher involvement and adherence rates. However, the veracity of this hypothesis can be questioned, since little is actually known regarding the association between activity doses and affective responses. The few preliminary attempts at the conceptual delineation of the dose-response relationship, all centred around an 'inverted-U' notion, are reviewed and criticised as lacking empirical foundation. Available meta-analyses, as well as the empirical literature on the role of exercise intensity and duration, are examined. Increased intensity appears to be associated with reduced positivity of affect during and immediately following an exercise bout. Intensity effects appear to be attenuated during recovery. Fitness and training status appear to become significant mediators of the exercise-affect relationship only at high intensities. With intensity being kept constant, different exercise bout durations have not been shown to have a differential impact on pre- to post-exercise affective changes. Recommendations for future research include: (i) a shift from categorical to dimensional conceptualisations and operationalisations of affect; (ii) the examination of psychological theories on the association between activation and affect (e.g. extraversion-introversion, sensation seeking, type A behaviour pattern and related self-evaluative tendencies, reversal theory, optimal stimulation theory, multidimensional activation theory and self-efficacy); (iii) the systematic and theory-based examination of in-task and post-exercise affective responses; (iv) the incorporation of the parameter of fitness and/or activity status in research designs; and (v) the re-evaluation of methods for selecting exercise intensity levels.

Emotions↗
PubMed1998

Selected physiological and psychological responses to live-fire drills in different configurations of firefighting gear.

The purpose of this study was to examine selected physiological and psychological responses to strenuous live-fire drills in different configurations of protective firefighting gear. Career firefighters (n = 10) performed three sets of firefighting drills in a training structure that contained live fires in two different configurations of firefighting gear. On separate days subjects wore: (a) the NFPA 1500 (1987) standard configuration, and (b) a hip-boot configuration of the firefighting gear. Physiological and psychological measurements were recorded pre-activity and at the end of each trial. Repeated measures ANOVA revealed a strong trend for performance time to be greater in the 1500 gear than in the hip-boot gear. There was a significant Time x Gear interaction for tympanic membrane temperature, with temperature being greater in the 1500 gear. Perceptions of effort and thermal sensations were also greater in the 1500 gear than in the hip-boot configuration of the gear. There was little difference in mean performance on cognitive function measures between the two gear configurations, but there was greater variability in performance in the 1500 gear. These data suggest that performing strenuous firefighting drills in the current NFPA 1500 standard configuration results in longer performance time, greater thermal strain, and greater perception of effort and thermal sensation.

Adult↗
PubMed1997

The effects of different thermal environments on the physiological and psychological responses of firefighters to a training drill.

Little is known about the impact of thermoregulatory demands on cardiovascular and psychological responses of firefighters during firefighting activities. This study examined selected responses to a training drill in different thermal environments. Male firefighters (n = 16) were randomly assigned to perform a simulated ceiling overhaul task for 16 min in either a neutral (13.7 degrees C) or hot (89.6 degrees C) condition while wearing standard firefighting turnout gear. Physiological and psychological measures were assessed before, after 8 min and 16 min of firefighting activity, and following a 10-min recovery period. The variables assessed included heart rate (HR), tympanic temperature (Ttymp), lactate level (LAC), blood glucose level, ratings of perceived exertion (RPE), perceptions of respiration, thermal sensations (TS) and state anxiety (SA). Significant increases were seen for HR, Ttymp, LAC, RPE and SA, with the increases being much greater following the hot condition. Recovery was significantly slower following work in the hot condition. These findings suggest that the addition of a live fire (a common situation for firefighters) contributes to increased cardiovascular and psychological strain at a standardized workload.

Adult↗
PubMed1997

Brain activation, affect, and aerobic exercise: an examination of both state-independent and state-dependent relationships.

Resting electroencephalograph (EEG) asymmetry is a biological marker of the propensity to respond affectively to, and a measure of change in affect associated with, acute aerobic exercise. This study examined the EEG-affect-exercise relationship. Twenty participants performed each of three randomly assigned 30-min conditions: (a) a nonexercise control, (b) a cycling exercise at 55% VO2max, and (c) a cycling exercise at 70% VO2max. EEG and affect were assessed pre- and 0, 5, 10, 20, and 30 min postcondition. No significant results were seen in the control or 55% conditions. In the 70% exercise condition, greater relative left frontal activation preexercise predicted increased positive affect and reduced state anxiety postexercise. Participants (n = 7) with extreme relative left frontal activation postexercise reported concomitant decreases in anxiety, whereas participants (n = 7) with extreme relative right frontal activation postexercise reported increases in anxiety. These findings (a) replicate prior work, (b) suggest a dose-response intensity effect, and (c) support the idea that exercise is an emotion-eliciting event. Affective responses seem to be mediated in part by differential resting levels of activation in the anterior brain regions. Ongoing anterior brain activation reflected concurrent postexercise affect.

Adult↗
PubMed1997

Affective responses to acute exercise: a test of opponent-process theory.

Based on Solomon's Opponent-Process theory (1980), it was predicted that individuals involved in a regimen of regular aerobic exercise (active; n = 18) would respond to an acute bout of exercise with reduced negative and/or increased positive affect compared to nonactive counterparts (nonactive; n = 12). State Anxiety (SA), positive affect (PA), negative affect (NA), and self-reported fatigue were assessed immediately prior to, every 6 min during, and every 6 min following a 24 min bout of bicycle exercise performed at an RPE of 13 (+/- 1). As expected, no significant group differences occurred for RPE (M = 13.5 for nonactive, 13.2 for active). The active group did, however, exercise at a greater absolute workload than the nonactive group (261.0 +/- 22.4 W vs 200.0 +/- 19.98 W, respectively). Analyses indicated similar changes in SA and fatigue for both groups, with significant reductions in SA occurring at 6 min post-exercise and remaining below pre-exercise levels throughout the post-exercise period, while fatigue was reduced at 12, 18, and 24 min post-exercise. A significant Group x Time interaction occurred for affective valence (PA - NA; p < .01). Post hoc analyses indicated that for the active group, affect increased modestly (i.e., more PA, less NA) during exercise; this increase was sustained post-exercise. The nonactive group evidenced a sharp drop in affect (i.e., less PA, more NA) during exercise followed by a small post-exercise rise which did not return to pre-exercise levels. The results of the present study partially support the Opponent-Process model as an explanation for exercise-related affect. Although there was no differential anxiety response as a function of activity level as the model would predict, there was a differential response for affective valence in accordance with predictions.

Adult↗
PubMed1996

Changes in electroencephalographic activity associated with learning a novel motor task.

This study was designed to examine changes in EEG activity associated with the learning of a novel task. Right-handed adults (N = 61) were randomly assigned to experimental and control groups. Subjects'EEG was recorded at 10 sites. Subjects' performance was assessed using 8-s trials on a mirror star trace. On the acquisition day, the experimental subjects performed 175 trials while the control subjects performed 10 trials, sat quietly for the amount of time needed to perform 155 trials, and then performed 10 more trials. On the retention day, all subjects performed 20 trials. There was a significant Group x Day x Trial interaction that showed that performance improved across trial blocks and across days; however, after the first 10 acquisition trials, the experimental subjects were always significantly better than the control subjects. Analysis of the EEG data showed a significant four-way interaction that showed that following the the first 10 acquisition trials, the experimental subjects had more alpha activity than the control subjects. It is concluded that there are consistent EEG changes in the alpha band that are associated with learning a motor task.

Adult↗
PubMed1996

The effects of acute and chronic exercise on sleep. A meta-analytic review.

Studies attempting to ascertain the effects of acute and chronic exercise on measures of sleep have yielded conflicting results and interpretations. Methodological differences among studies may explain this lack of consensus; however, small sample sizes and subsequently low statistical power may also have contributed. In an attempt to resolve these issues, this review used meta-analytical techniques to: (a) re-examine the effects of exercise on sleep; and (b) examine possible moderators of these effects. Studies meeting the selection criteria were included in the analysis. Analyses of moderating factors were performed for stage 4 sleep and rapid eye movement (REM) sleep. The results indicated that acute and chronic exercise increased slow wave sleep (SWS) and total sleep time but decreased sleep onset latency and REM sleep. Moderating variables influencing the magnitude and direction of these effects were related to characteristics of the individual (e.g. sex, age, fitness level) and the exercise (e.g. time of day exercise was completed, type of exercise, exercise duration). Mechanisms which have been suggested to explain the relationship between exercise and sleep are discussed and directions for further research are provided.

Exercise↗
PubMed1996

Physiological, psychophysical, and psychological responses of firefighters to firefighting training drills.

This study was designed to describe the physiological, psychophysical, and psychological responses of firefighters to firefighting drills in a training structure containing live fires. Fifteen male firefighters, wearing standard turnout gear which resulted in full encapsulation, performed two firefighting tasks (advancing fire hose, chopping wood) while inside the training structure. Measurements of heart rate, tympanic membrane temperature, blood lactate, perceptions of respiration, mood, perceived exertion, and thermal sensation were obtained after 8 min of advancing fire hose, and again after 8 min of chopping. Heart rate and temperature increased significantly from baseline and from advancing hose to wood chopping, whereas blood lactate increased initially after advancing the hose and remained elevated at the end of the chopping task. At the completion of the test (both tasks), mean heart rate (182.3 b.min-1), temperature (40.1 degrees C, [104.1 degrees F]), and blood lactate (3.8 mMol) suggested that the firefighting tasks used in this study impose considerable physiological strain on firefighters. Psychophysical and psychological data mirrored the greater physiological strain following firefighting tasks performed in a hot environment while wearing full turnout gear.

Adult↗
PubMed1995

Anxiety responses to maximal exercise testing.

The influence of maximal exercise testing on state anxiety was examined in three separate studies. Highly trained male distance runners (Study 1, n = 12) as well as college students with average (Study 2, n = 16) and below average (Study 3, n = 32) physical fitness levels completed graded maximal exercise tests. This last group was also randomly assigned to either a control or an 8 week training programme in order to determine the effect of increased fitness on the psychological responses to maximal exercise testing. Physical fitness was determined by the measurement of maximal oxygen uptake. State anxiety (State-Trait Anxiety Inventory) was assessed before and from 2-15 min following exercise. It was found that the state anxiety responses to maximal exercise testing were not influenced by re-testing or by 8 weeks of endurance training. Across the three study groups, the anxiety response was variable during the first 5 min following exercise testing; increases, decreases and no changes in anxiety were observed when compared to pre-exercise levels. The anxiety response to maximal exercise appeared to be dependent on the pre-exercise anxiety levels as well as the timing of the post-exercise assessments. It is concluded that maximal exercise testing can be associated with negative mood shifts during the first 5 min after exercise; however, this response is transitory and followed by positive mood shifts 10-15 min following such tests.

Adult↗
PubMed1995

Varying the intensity of acute exercise: implications for changes in affect.

Little is known regarding effects of components of the exercise stimulus (e.g., intensity, duration) on affective responses. The effect of varying levels of exercise intensity was examined for state anxiety (SA), positive affect (energetic arousal; EA), and negative affect (tense arousal; TA). Twenty subjects (M age = 22.6 years; M VO2 max = 47.8 ml.kg-1.min-1) participated in 3 randomly assigned conditions: (a) no exercise (control), (b) cycling@ 55% VO2max, and (c) cycling@ 70% VO2max. After being seated on an exercise bike, subjects completed the affect measures and were then told what condition they had been assigned for that day. Subjects either exercised or sat quietly on the bike for 30 min. Affect measures were obtained during exercise (or control), upon cessation of each condition, and then during the 30 min post-condition period. No changes occurred for the control condition on any variables. SA increased (p < 0.05) for both intensities during exercise followed by a significant post-exercise reduction only in the 70% VO2max condition. EA increased (p < 0.05) during exercise and remained elevated following both exercise intensities; increased EA was maintained to a greater extent following the 70% intensity condition (p < 0.05). These findings suggest that aerobic exercise (55-70% VO2max) elicits not only decreases in negative feeling states (state anxiety) but also increases in positive affect. Further, there is some evidence that such changes may be dependent on exercise intensity.

Adult↗
PubMed1994

State anxiety reduction and exercise: does hemispheric activation reflect such changes?

Acute bouts of aerobic exercise have been consistently associated with significant reductions in anxiety, but explanations for this effect remain elusive. The cerebral lateralization hypothesis predicts that anxiety reductions would be caused by a postexercise decrease in anterior right, relative to left, hemisphere activation. A sample of 19 right-handed males ran at 75% of their VO2max for 30 min on a treadmill. Electroencephalogram (EEG; F3, F4, T3, T4) and state anxiety were collected before and following exercise. Compared with preexercise, anxiety was significantly (P < 0.05) reduced at 10, 20, and 30 min postexercise. Preexercise EEG alpha asymmetry was significantly related to trait anxiety and also predicted a significant amount of variance (30%; P = 0.008) in postexercise anxiety reduction. From pre- to postexercise, the relative activation of the left frontal area increased with respect to the homologous right frontal site. Within-subject correlations for the change in anxiety with corresponding EEG changes were small but in line with theoretical predictions. It is concluded that the cerebral lateralization hypothesis remains tenable for explaining anxiety reductions associated with exercise.

Adult↗
PubMed1992

Spontaneous eyeblinks and state anxiety following exercise.

The purposes of this investigation were: (1) assess the impact of acute exercise on spontaneous eyeblink rate, and (2) determine the relationship between eyeblinks and state anxiety before and following exercise. Sixteen men performed a graded treadmill run for the purpose of assessing maximal oxygen uptake (VO2max). On three separate days the subjects completed a 15 min run at 75% of VO2max, a 30 min run at 75% of VO2max, and a control condition which involved 15 min of imagined running. State anxiety and eyeblink rate were assessed immediately before as well as 5, 10, 20, and 30 min following each condition. Multivariate ANOVA (3 Conditions x 5 Trials) with repeated measures revealed a significant main effect for trials (Wilks' Lambda = .80; F = 2.5; df = 4.42; p = .05) for eyeblink rate. One-way ANOVA post hoc tests indicated that eyeblinks increased significantly following the imagined exercise condition only. A significant main effect for trials (Wilks' Lambda = .47; F = 12.1; df = 4.42; p < .001) was also found for state anxiety, and following all three conditions significant reductions in anxiety were observed when compared to precondition values. Significant correlations were not observed between eyeblink rate and state anxiety following any of the three conditions; however, a moderate relationship was found immediately prior to each condition (range: r = .30-.43). It is concluded that eyeblink rates are not influenced by treadmill running at 75% of VO2max for either 15 or 30 min, and that postexercise anxiety reductions are unrelated to eyeblink rates.

Adult↗
PubMed1991

A meta-analysis on the anxiety-reducing effects of acute and chronic exercise. Outcomes and mechanisms.

The relationship between exercise and anxiety has been extensively examined over the last 15 years. Three separate meta-analysis were conducted to quantitatively review the exercise-anxiety literature for state anxiety, trait anxiety and psychophysiological correlates of anxiety. Such a procedure allows tendencies of the research to be characterised. The results substantiate the claim that exercise is associated with reductions in anxiety, but only for aerobic forms of exercise. These effects were generally independent of both subject (i.e. age and health status) and descriptive characteristics. Numerous design characteristics were different, but these differences were not uniform across the 3 meta-analyses. For state anxiety, exercise was associated with reduced anxiety, but had effects similar to other known anxiety-reducing treatments (e.g. relaxation). The trait anxiety meta-analysis revealed that random assignment was important for achieving larger effects when compared to the use of intact groups. Training programmes also need to exceed 10 weeks before significant changes in trait anxiety occur. For psychophysiological correlates, cardiovascular measures of anxiety (e.g. blood pressure, heart rate) yielded significantly smaller effects than did other measures (e.g. EMG, EEG). The only variable that was significant across all 3 meta-analyses was exercise duration. Exercise of at least 21 minutes seems necessary to achieve reductions in state and trait anxiety, but there were variables confounding this relationship. As such, it remains to be seen what the minimum duration is necessary for anxiety reduction. Although exercise offers therapeutic benefits for reducing anxiety without the dangers or costs of drug therapy or psychotherapy, it remains to be determined precisely why exercise is associated with reductions in anxiety. Since several mechanisms may be operating simultaneously, future research should be designed with the idea of testing interactions between these mechanisms.

Acute Disease↗