Search PubMed⌕ Search

Biomedical subjects

W P Morgan

Publications and source records attributed to W P Morgan.

At least 19 recordsLinked to original sources
PubMed2004

Trait anxiety predicts panic behavior in beginning scuba students.

Recreational scuba diving is associated with a significant number of fatalities and decompression illnesses each year, and there is evidence that permanent neuropsychological injury can occur in divers. There is also evidence that the principal cause of decompression illness and fatalities in divers is rapid ascent, and it appears that the primary stimulus for rapid ascent is panic. The primary purpose of this investigation was to evaluate the extent to which an objective measure of trait anxiety could be effective in predicting panic behavior in students undergoing scuba training. Trait anxiety was assessed at the outset of scuba instruction in 42 students, and the instructor recorded instances of panic behavior during the 4-month course. It was predicted that individuals scoring 39 or greater on the trait anxiety sub-scale of the State-Trait Anxiety Inventory would be more likely to experience panic behavior than individuals with scores below this cut-off. Predictions and actual recordings of panic behavior were performed independently using a blinded paradigm. Eleven of the students exhibited panic behavior on two or more occasions during the instruction, and 35 of 42 (83 %) predictions were accurate (p < 0.001). It is concluded that an objective measure of trait anxiety can be employed a priori for prediction of panic behavior in beginning scuba students.

Adult↗
PubMed2002

Brain activation by central command during actual and imagined handgrip under hypnosis.

The purpose was to compare patterns of brain activation during imagined handgrip exercise and identify cerebral cortical structures participating in "central" cardiovascular regulation. Subjects screened for hypnotizability, five with higher (HH) and four with lower hypnotizability (LH) scores, were tested under two conditions involving 3 min of 1) static handgrip exercise (HG) at 30% of maximal voluntary contraction (MVC) and 2) imagined HG (I-HG) at 30% MVC. Force (kg), forearm integrated electromyography, rating of perceived exertion, heart rate (HR), mean blood pressure (MBP), and differences in regional cerebral blood flow distributions were compared using an ANOVA. During HG, both groups showed similar increases in HR (+13 +/- 5 beats/min) and MBP (+17 +/- 3 mmHg) after 3 min. However, during I-HG, only the HH group showed increases in HR (+10 +/- 2 beats/min; P < 0.05) and MBP (+12 +/- 2 mmHg; P < 0.05). There were no significant increases or differences in force or integrated electromyographic activity between groups during I-HG. The rating of perceived exertion was significantly increased for the HH group during I-HG, but not for the LH group. In comparison of regional cerebral blood flow, the LH showed significantly lower activity in the anterior cingulate (-6 +/- 2%) and insular cortexes (-9 +/- 4%) during I-HG. These findings suggest that cardiovascular responses elicited during imagined exercise involve central activation of insular and anterior cingulate cortexes, independent of muscle afferent feedback; these structures appear to have key roles in the central modulation of cardiovascular responses.

Blood Pressure↗
PubMed2001

Affective and metabolic responses to hypnosis, autogenic relaxation, and quiet rest in the supine and seated positions.

This study examined the influence of hypnosis, autogenic relaxation, and quiet rest on selected affective states and metabolism. The influence of body position (seated vs. supine) on these same outcome measures was also investigated. Anxiety, tension, and overall mood were assessed before and 30 minutes after each treatment, and oxygen uptake was measured continuously. State anxiety, tension, and a general measure of mood were reduced significantly following each intervention, but oxygen uptake did not change with the exception of small, transient alterations during the physical challenges performed in the hypnosis condition. It is concluded that administration of a routine hypnosis induction to healthy individuals results in a reduction of state anxiety and an improvement of mood commensurate with effects achieved by autogenic training and quiet rest, and these effects occur in both the supine and seated position.

Adolescent↗
PubMed2001

Hypnotic manipulation of effort sense during dynamic exercise: cardiovascular responses and brain activation.

The purpose of this investigation was to hypnotically manipulate effort sense during dynamic exercise and determine whether cerebral cortical structures previously implicated in the central modulation of cardiovascular responses were activated. Six healthy volunteers (4 women, 2 men) screened for high hypnotizability were studied on 3 separate days during constant-load exercise under three hypnotic conditions involving cycling on a 1) perceived level grade, 2) perceived downhill grade, and 3) perceived uphill grade. Ratings of perceived exertion (RPE), heart rate (HR), blood pressure (BP), and regional cerebral blood flow (rCBF) distributions for several sites were compared across conditions using an analysis of variance. The suggestion of downhill cycling decreased both the RPE [from 13 +/- 2 to 11 +/- 2 (SD) units; P < 0.05] and rCBF in the left insular cortex and anterior cingulate cortex, but it did not alter exercise HR or BP responses. Perceived uphill cycling elicited significant increases in RPE (from 13 +/- 2 to 14 +/- 1 units), HR (+16 beats/min), mean BP (+7 mmHg), right insular activation (+7.7 +/- 4%), and right thalamus activation (+9.2 +/- 5%). There were no differences in rCBF for leg sensorimotor regions across conditions. These findings show that an increase in effort sense during constant-load exercise can activate both insular and thalamic regions and elevate cardiovascular responses but that decreases in effort sense do not reduce cardiovascular responses below the level required to sustain metabolic needs.

Adult↗
PubMed1997

Influence of time of day on the anxiolytic effects of exercise.

The purpose of this investigation was to study state anxiety responses associated with running at different times of day. Thirty volunteers (15 Female and 15 Male) who regularly exercised in the morning (n = 10), at noon (n = 10), or in the evening (n = 10) completed three running sessions at 0600 h-0800 h, 1100 h-1300 h, and 1600 h- 1800 h. A post-hoc analysis was also performed comparing individuals who ran at their preferred time (N = 18) with individuals who ran at a time different from their preferred time (N = 11). The duration and pace of these runs were based upon each runner's "preferred exertion", and this was held constant across trials for each participant. The estimated metabolic cost did not differ across the three sessions, but there was a significant difference between Female (mean = 11.4 METS) and Male (mean = 12.9 METS) runners. The dependent variables were state anxiety, perceived exertion, heart rate, tympanic temperature and blood pressure. Data were analyzed by means of repeated measures MANOVA for multifactor experiments. State anxiety was reduced significantly (p < 0.05) for both the women and men, and this effect was independent of time of day. Furthermore, this effect occurred regardless of whether or not the individual's usual exercise time was the preferred time. Perceived exertion increased significantly (p < 0.05) from half-way through to the end of the run and this response occurred regardless of time of day. None of the remaining variables were influenced by time of day. It is concluded that the anxiolytic effects of running exercise are independent of the time of day the exercise is performed.

Adult↗
PubMed1997

Influence of acute physical activity and relaxation on state anxiety and blood lactate in untrained college males.

The purpose of this investigation was to evaluate the acute effects of physical activity and relaxation on state anxiety and blood lactate. Thirty male Ss performed resistance exercise (N=15) or cycling (N=15) for 50 min at 70% of maximum, while 30 additional male Ss practiced autogenic relaxation (N=15) or rested quietly (N=15) in a sound chamber for 50 min. Assessment of state anxiety and blood lactate was performed before, 5-10 min and 60 min following treatments. The data were analyzed with a repeated measures ANOVA for multifactor experiments, and results indicate a significant group by trial interaction for state anxiety (p<0.0001) and lactate (p < 0.0001). Post-hoc analysis revealed that: 1. lactate increased (p<0.001) immediately following resistance exercise and fell to baseline levels 60 min post exercise; 2. state anxiety was decreased (p < 0.01) at 5-10 min following autogenic relaxation and quiet rest; and 3. a reduction (p < 0.001) in state anxiety was noted at 60 min following cycling. It is concluded that: 1. comparable anxiolytic effects occur following aerobic exercise (cycling), autogenic relaxation and quiet rest, but the effect persists for a longer period of time following aerobic exercise; and 2. accumulation of lactate does not influence state anxiety in normal individuals.

Adult↗
PubMed1997

Influence of wet suit wear on anxiety responses to underwater exercise.

The purpose of this investigation was to evaluate the effect of wearing a wet suit on selected psychological and physiologic variables. Certified divers (n = 13) finned underwater at 0.52 m/s for 20 min with and without a wet suit. Order was randomly assigned and performed on separate days. Heart rate, respiration rate, use of compressed air, ratings of perceived exertion, and breathing ratings increased significantly (P < 0.05) for both conditions, and increases in heart rate, use of compressed air, and breathing ratings were significantly greater for the wet-suit condition. Rectal temperature increased significantly (P < 0.001) for the wet-suit but not the bathing-suit condition. State anxiety and body awareness increased (P < 0.001) following the wet-suit condition. Furthermore, state anxiety decreased significantly (P < 0.001) by 15 min after exercise in the bathing-suit condition. It is concluded that wet suit wear can result in elevated anxiety when performed at a water temperature and exercise intensity sufficient to produce increased core temperature.

Adult↗
PubMed1996

Selected psychological characteristics and health behaviors of aging marathon runners: a longitudinal study.

This report summarizes the health behaviors and psychological characteristics of fifteen male marathon runners who were first tested in 1969 (N = 8) and 1976 (N = 7). The participants in this study averaged 29 years of age at the outset, and the mean age at the time of follow-up was 50 years. These subjects were found to score in the normal range on all of the psychological variables, and they were characterized by the "iceberg" profile described earlier for elite athletes in various sports. This profile includes scores that fall below the population average on mood states such as tension, depression, anger, fatigue and confusion along with above average scores on vigor. Also, the psychological traits of these former runners have been remarkably stable across the past two decades, with the exception that a uniform decline has been observed for the neuroticism measure. Earlier research by Eysenck has shown that neuroticism decreases with age. These former marathon runners continue to be moderately active, and it is noteworthy that they first became involved as runners while in high school. All but one of the participants had attended college, and each had participated in competitive running while in college. Training for marathon competition took place following the college years. It is likely that much of the early success enjoyed by this group was governed to a substantial degree by heredity. This sample possessed an average aerobic power of 70 ml.kg-1.min-1 along with a unique somatotype when first tested, and these factors are known to have a substantial heritability component. The health behaviors studied in this group were uniformly positive. They were found to be physically active, and their physical self-esteem fell above that of other men in their age group. The subjects reported moderate use of alcohol, no insomnia, few physical problems and good overall mood. The sample of former marathon runners described in this report is unique in a number of respects, and caution is urged in making generalizations. With this qualification in mind, it is concluded that a lifetime of regular physical activity is associated with desirable physical and mental health.

Adult↗
PubMed1996

Psychometric correlates of perception during arm ergometry in males and females.

This study examined psychometric correlates of rated perceived exertion (RPE) and perceived dyspnea (RPD) during progressive arm ergometry. Thirty female and 30 male subjects completed the State-Trait Anxiety Inventory (STAI), the Profile of Mood States Questionnaire (POMS) and the Body Awareness Scale (BAS) followed by progressive arm ergometry to exhaustion. Heart rate, minute ventilation, RPD and RPE were obtained during the last 30 seconds of every two minute stage of the exercise test. The female group had significantly (p < 0.05) higher RPE (overall and local), RPD, minute ventilation, and heart rate than did the male group during exercise at absolute power outputs of 33, 50 and 67 watts. At each of these work loads, both state anxiety and body awareness were positively and significantly (p < 0.05) related to RPE and RPD in the male but not in the female sample. Repeated measures ANOVAs revealed that a subset of high trait anxious males (N = 10) exhibited higher minute ventilatory volumes and dyspnea ratings than a subset of low trait anxious males (N = 10). The results show that elevated trait anxiety is associated with dyspnea during arm ergometry and that there are gender differences in psychological correlates of perception during arm exercise, but shed no light on why the gender differences exist.

Adult↗
PubMed1996

Psychological consequences of exercise deprivation in habitual exercisers.

Psychological consequences of exercise deprivation in habitual exercisers. The purpose of this investigation was to evaluate the influence of 3 d of exercise deprivation on selected psychological variables. Ten volunteers (4 female and 6 male) who regularly exercised 6-7 d.wk-1 for at least 45 min at a time participated in a 5-d study. Participants completed their regular workout on the first day of the study, refrained from physical activity for the next 3 d, and then resumed their regular exercise on the 5th d of the study. Participants reported to the lab on Monday following their regular workout and completed a series of questionnaires, and these same questionnaires were completed at the same time of day on the next 4 d. The dependent variables consisted of state and trait anxiety (STAI), and tension, depression, anger, vigor, fatigue, confusion, and overall mood (POMS). Increases in total mood disturbance, state anxiety, tension, depression, and confusion across days were significant (P < 0.05), and vigor decreased. The pattern of increasing mood disturbance with exercise deprivation was followed by mood improvement to baseline levels when exercise was resumed. We concluded that a brief period of exercise deprivation in habitual exercisers results in mood disturbance within 24-48 h.

Adult↗
PubMed1996

Responses to underwater exercise in scuba divers differing in trait anxiety.

Fifteen male scuba divers performed underwater leg ergometer exercise in an effort to determine if trait anxiety was related to their physiologic or perceptual responses. Psychologic assessment completed before exercise testing revealed that the sample exhibited positive psychologic profiles. However, five individuals possessed trait anxiety scores above the published mean (M = 46.0). Their responses to exercise were compared with the five participants with the lowest trait anxiety scores (M = 30.6). The exercise task was 20 min of steady-state underwater leg ergometer exercise. Oxygen consumption, CO2 production, minute ventilatory volume, breathing frequency, and heart rate were assessed at rest and every 5 min during exercise. Perception of effort and breathing discomfort were also determined during exercise. Each of the physiologic and perceptual variables increased (P < 0.05) with exercise. The only group main effect (P < 0.05) occurred for respiration rate. The high trait anxious group took 7.4 fewer breaths per minute (13.1 vs. 20.5) compared with low trait anxious group. These results have implications regarding the use of intervention strategies in persons at potential risk of experiencing panic while scuba diving.

Adult↗
PubMed1995

Influence of weight training on state anxiety, body awareness and blood pressure.

The primary purpose of this investigation was to evaluate the effect of one session of recreational weight training on state anxiety and related constructs. State anxiety, body awareness and blood pressure were evaluated before and within 5-min following 50-min of self-selected weight training activity in a group of 25 subjects, and following 50-min of non-activity for 25 control subjects. Repeated measures ANOVA revealed that state anxiety did not change (p > 0.05) significantly following weight training or quiet rest. However, there was a significant (p < 0.05) increase in body awareness in the weight training group, as well as a significant (p < 0.05) trials by conditions interaction in systolic blood pressure. The control group experienced a decrease in systolic blood pressure of 5 mmHg, whereas the exercise group had an increase in blood pressure of 5 mmHg. It is concluded that state anxiety is not altered immediately following one session of recreational weight training activity, but this activity does produce increases in body awareness and systolic blood pressure.

Adult↗
PubMed1995

Influence of time of day on psychological responses to exercise. A review.

Circadian rhythms have been documented for various physiological variables, such as body temperature, heart rate, blood pressure, cortisol, adrenaline (epinephrine) and noradrenaline (norepinephrine) under resting, as well as exercise conditions. The extent to which psychological variables, such as perception of effort, mood states and anxiety, are subject to circadian rhythms at rest and during exercise, is not as well understood. Body temperature follows a circadian rhythm in which temperature is highest in the evening and lowest in the early morning. Exercise heart rate follows a similar rhythm, but peaks a little earlier. The findings for exercise blood pressure are not consistent. Performance of physical activity is generally improved in the afternoon or evening, compared with morning. Cortisol levels follow a circadian rhythm in which cortisol peaks in the morning and decreases throughout the rest of the day, at rest and during exercise. Plasma catecholamines show a rhythm at rest, but the findings during exercise are inconsistent. Research on circadian rhythms of perceived exertion and mood states are equivocal and the limited research on anxiety suggests that the anxiolytic response to exercise is not influenced by time of day.

Affect↗
PubMed1995

Anxiety and panic in recreational scuba divers.

Scuba diving is a high-risk sport; it is estimated that 3 to 9 deaths per 100,000 divers occur annually in the US alone, in addition to increasing numbers of cases of decompression illness each year. However, there has been a tendency within the diving community to de-emphasise the risks associated with scuba diving. While there are numerous factors responsible for the injuries and fatalities occurring in this sport, there is general consensus that many of these cases are caused by panic. There is also evidence that individuals who are characterised by elevated levels of trait anxiety are more likely to have greater state anxiety responses when exposed to a stressor, and hence, this sub-group of the diving population is at an increased level of risk. Efforts to demonstrate that selected interventions such as hypnosis, imagery, mediation and relaxation can reduce stress responses in anxious divers has not yielded consistent findings, and there is a need for systematic research dealing with the efficacy of selected intervention strategies.

Accidents↗
PubMed1994

Development of a scale for use in monitoring training-induced distress in athletes.

In an attempt to identify athletes at risk of training-induced distress, a scale was developed using items from the Profile of Mood States (POMS). POMS data were collected monthly from 170 varsity college swimmers (70 female, 100 male) during four competitive training seasons. The team coaches identified swimmers who showed signs of compromised performance in response to intensive training (i.e., distress), and several series of discriminant function analyses were conducted in attempts to identify these individuals using POMS scale items. Discriminant function equations derived from subsets of items from the entire POMS items pool resulted in a mean prediction rate for identifying distressed swimmers of 93.9% for men and 100% for women. Seven POMS items which entered the equations most frequently served as predictor variables for analyses of a sample of 33 men swimmers. Predictions of distress were conducted at each monthly assessment. The prediction rate of distress achieved with the 7-item set of POMS items averaged 69.1%, and this level of accuracy was 37.0% above the chance rate of prediction (p < 0.05). In a cross-validation on 29 collegiate track and field athletes, the prediction rate of the 7-item scale was 66.7% (p < 0.05). It is concluded that the scale developed in this investigation was effective in identifying swimmers and other endurance athletes who exhibit signs of distress resulting from intensive training.

Depression↗
PubMed1994

Evaluation of the ergogenic properties of ginseng.

Ginseng has been used for several thousand years in the Orient as a tonic, prophylactic agent and 'restorative'. However, its efficacy has been established primarily through clinical experience as opposed to scientific verification of its pharmacological effects. Ginseng has been used by athletes as an ergogenic aid for many years, but there is an absence of compelling research evidence in support of its use for this purpose. Indeed, most of the support favouring the use of ginseng to enhance physical performance is of a testimonial nature. While studies with animals show that ginseng or its active components may prolong survival to physical or chemical stress, there is, generally, a lack of controlled research demonstrating the ability of ginseng to improve or prolong performance in fatigued humans.

Animals↗
PubMed1994

Psychological components of effort sense.

The perception of effort is multidimensional and it is governed by many physiological, psychological, and experiential factors. This paper deals with a discussion of selected psychological states and traits that are known to be correlated with the expression of effort sense. It has been shown that anxiety, somatic perception, depression, and neuroticism are associated with perceived exertion. Extroversion has been found to be inversely correlated with perceived exertion, and positively correlated with preferred exercise intensity. These empirical findings are congruent with theoretical expectations in each case. It has also been found that perception of effort can be increased and decreased in a systematic manner with various psychological interventions such as hypnotic suggestion, dissociative cognitive strategies, and imagery. Changes in effort sense can also be systematically modified by titrating exercise volume (e.g., overtraining, tapering), and this exercise-induced alteration in perception covaries with affective changes. The research reviewed in this paper supports the conclusion that effort sense is best conceptualized as a complex psychobiological construct as originally proposed by Borg three decades ago.

Anxiety↗