Author: Alex

D.L. Smith, S.J. Petruzzello, J.A. Woods, M.A. Chludzinski & J.J. Reed; Skidmore Coll., Saratoga Springs, NY; Univ.of Illinois and Covenant M.C., Urbana, IL

The purpose of this study was to describe changes in blood chemistry, blood volume, and blood cell counts following strenuous firefighting activities performed in a building that contained live fires. Subjects were 11 male, career firefighters (M age = 31.8 yrs, Ht = 180.7 cm, Wt = 86.1 kg). Subjects completed 3 trials of a standardized set of tasks (carrying and using a fire extinguisher, hoisting hose, chopping wood, dragging a dummy,) in a training structure that contained live fires. Each trial took an average of about 6 min and subjects were given a 10 minute rest period between Trials 2 and 3. Blood samples were drawn prior to initiating the drills, within 1 minute of completing the drills, and following a 1 hour recovery period. ANOVA with Tukey post-hoc analysis revealed significant differences among the three sample periods for a) plasma volume, b) white blood cell count (including subsets) and c)10 of the 19 variables assessed via a standard blood chemistry panel. These data indicate that strenuous firefighting activity performed in a hot and hostile environment results in changes in blood volume, blood cell counts and in blood chemistry. The change in plasma volume (a 15% decrease) is in agreement with published data regarding strenuous exercise in a hot environment. The changes in blood chemistry and white blood cell counts provides further evidence as to extent of physiological disruption that can occur with strenuous firefighting activity.

Supported by Skidmore Faculty Initiative Grant.

T Van Staveren, S Achord, EE Hall, P Ekkekakis, & SJ Petruzzello, PhD, FACSM, Department of Kinesiology, University of Illinois, Urbana, IL

Both aerobic exercise and relaxation training have been show to improve well-being through reductions in negative affect and enhancement of positive affect. This study examined the effects of exercise and guided relaxation on affect and brain activation. 19 adults (10 , 9 ; 22.7 yrs) participated in both randomly assigned conditions: (a) 30 min of treadmill running @ 75% VO₂max; (b) 25 min of verbally guided relaxation. Brain activation (EEG; F3, F4, referenced to linked ears), state anxiety (SAI), and energetic arousal were assessed at Pre, 0-, 10-, 20-, and 30 min post-condition. EEG asymmetry scores (R-L alpha) were compared with respect to changes in emotional state. Despite no significant change in alpha activity in the exercise condition, frontal asymmetry was related to state anxiety [r(17)= -0.51, P=0.02] immediately post-exercise, indicating greater left relative to right frontal activity (i.e., less alpha) was associated with lower state anxiety. No significant asymmetry-anxiety relationship was found for the relaxation condition. Relaxation resulted in alterations in theta and alpha band activity (P< 0.05), but did not change self-reported affect. Anxiety reduction was present only for the exercise condition from 0- to 10-min post compared to anxiety levels over the same time points in the relaxation condition (P=0.03). Exercise also resulted in increased energetic arousal that persisted for the entire post-treatment interval (P=0.003). Results suggest exercise may act as an emotion-eliciting event which is in part mediated by lateralized frontal brain activation. Relaxation resulted in altered EEG patterns, but had no appreciable impact on affective responses.

EE Hall & SJ Petruzzello, PhD, FACSM, Department of Kinesiology, University of Illinois, Urbana, IL

Physical activity has been consistently linked with better mental health (e.g., less anxiety, depression; more positive affect, satisfaction with life). Brain activation has also been linked to mental health, with greater relative left activation being related to more global positive affect and greater relative right activation being related to more global negative affect. Few studies have examined this relationship in older adults. Resting left and right hemisphere alpha activity (8-13 Hz; F3, F4, C3, C4, P3, P4, referenced to linked ears), mental health measures [positive affect (PA), trait anxiety (TA), depression (DEP), satisfaction with life (SWL), negative affect (NA)], and physical activity measures were obtained from 15 male and 26 female (M age=68.7±5.8 yrs) adults. Resting frontal asymmetry (R-L alpha) was related to PA (r=0.28, P=0.04; i.e., greater relative activation in left vs right related to more positive affect) in the total group (n=41). In the high active group (n= 21), frontal asymmetry was related to PA (r=0.49, P=0.01), NA (r=-0.39, P= 0.04), SWL (r=0.31, P=0.09), and DEP (r=-0.28, P=0.11). In the low active group (n=20), frontal asymmetry was related to NA (r=0.40, P=0.04) Physical activity was also related to PA (r=0.48, P= 0.001), SWL (r=0.48, P=0.001), DEP (r=-0.31, P=0.03), and TA (r=0.29, P=0.03). Physical activity is positively related to mental health in older adults and there is a relationship between positive affect and frontal brain asymmetry. This brain activation-mental health relationship appears to be mediated by physical activity in older adults.

Supported by a grant from the UIUC Office of Gerontology & Aging Studies.

E.E. Hall, P. Ekkekakis, & S.J. Petruzzello, University of Illinois, Urbana, IL 61801

Examination of affective responses to acute exercise using asymmetrical regional brain activation has shown resting EEG asymmetry to be a biological marker of an individual’s predisposition to respond affectively to aerobic exercise. Greater resting left anterior hemisphere activation, relative to the right, has been predictive of enhanced positive affective responses to such emotion-eliciting stimuli. To further examine this explanation with respect to exercise, regional brain activation measured via EEG (F3, F4, P3, P4; referenced to linked-ears) was assessed before treadmill running (30 min @ 75% VO₂max) in 69 subjects (38 males, 31 females; 21.5 ± 2.95 yrs).

Affect was assessed via a 10-item version of Spielberger’s State Anxiety Inventory (SA; Form Y-1) and Thayer’s ADACL, which yields measures of Energetic Arousal (EA) and Tense Arousal (TA; both SAI & ADACL had adequate reliability & validity). Affective measures were obtained before and 0, 10, 20, and 30 min post-exercise. Hierarchical regression analyses revealed that, after partialling out pre-exercise EA, resting frontal asymmetry accounted for 7% of the unique variance in EA (beta=.26, P=0.0065) at 10-min, 11% (beta=.34, P=0.0005) at 20-min, and 7% (beta=.26, P=0.0038) at 30-min post-exercise. Frontal asymmetry did not account for any unique variance in either SA or TA. Parietal EEG also failed to predict any affective responses.

Thus, relatively greater left frontal activation at rest predicted post-exercise increases in EA. These findings replicate previous exercise-EEG research and further support that exercise may be a significant emotion-eliciting event with affective responses being mediated, in part, by differential resting levels of activation in the anterior portions of the cerebral hemispheres.

Supported by NIMH RO3 MH55513-01.

S.J. Petruzzello, E.E. Hall, & P. Ekkekakis, University of Illinois, Urbana, IL 61801

Psychophysiology has become an important avenue for understanding various affective and cognitive phenomena within the exercise sciences. In particular, the use of EEG as a measure of brain activation has seen increasing use in recent years. Numerous discrepancies exist in the literature regarding outcomes from studies using different measurement protocols, but the extent to which certain factors might influence these outcomes is not known. It has been shown that body positions ranging from -12° head-down tilt to 45° head-up tilt result in a fairly linear decrease in EEG spectral power. The purpose of this study was to examine what the effect of different upright postures would be on EEG spectral power (4-20 Hz). Four, 60-s epochs of EEG were collected from 6 sites (F3, F4, C3, C4, P3, P4; referenced to linked ears) in 15 subjects. Subjects were placed in 3 different body positions (all head-up; 45° seated, 90° seated, standing). Repeated measures ANOVAs revealed that across EEG sites, there was a significant increase (Ps<0.015) in spectral power (8-20 Hz) as subjects went from a seated position to a standing position, with no differences between the two seated positions. Trends in the same direction occurred for slower frequencies (4-7 Hz). Coupled with previous data, it appears that there is a U-shaped relationship between body position and EEG spectral power, such that from head-down tilt to upright sitting, there is a fairly linear decrease in spectral power. As body position goes from upright sitting to standing, spectral power shows a significant increase, particularly in the frequency range from 8-20 Hz. The cause of this increase is unknown, but may be linked with loading of baroreceptors. Such a finding is important for exercise scientists using EEG techniques to examine relevant affective and cognitive variables.

Supported by NIMH RO3 MH55513-01.

E.E. Hall, P. Ekkekakis, & S.J. Petruzzello, University of Illinois, Urbana, IL 61801

Asymmetrical regional brain activation has been shown to be a biological marker of the predisposition to respond affectively to aerobic exercise. Unknown is the extent to which fitness may influence this relationship. Regional brain activation (via EEG: F3, F4, P3, P4; referenced to linked-ears) was assessed before treadmill running (30 min@75% VO₂max) in 67 subjects (37 males, 30 females; 21.4 ± 2.9 yrs). Aerobic fitness was determined from a graded treadmill exercise test. Affect was assessed before and 0, 10, 20, and 30 min post-exercise via Spielberger’s 10-item State Anxiety Inventory (SA; Form Y-1) and Thayer’s ADACL, which yields measures of Energetic Arousal (EA) and Tense Arousal (TA). Hierarchical regression analyses revealed that, after partialling out pre-exercise EA, resting frontal asymmetry accounted for 7% unique variance in EA (Beta =.26, P=0.0066) at 10-min, 11% (Beta =.34, P=0.0006) at 20-min, and 7% (Beta =.26, P=0.0037) at 30-min post-exercise. In the high fit group (n = 33), frontal asymmetry accounted for 17% unique variance in EA (Beta =.41, P=0.0006) at 10-min, 23% (Beta =.48, P=0.0002) at 20-min, and 16% (Beta =.40, P=0.0007) at 30-min post-exercise. In the low fit group (n = 34), frontal asymmetry did not account for any unique variance in EA. Neither frontal nor parietal EEG accounted for any unique variance in SA or TA for either group. Thus, relatively greater left frontal activation predicted post-exercise increases in EA and this relationship was influenced by level of aerobic fitness. These findings replicate previous exercise-EEG research and support the idea that affective responses to exercise are mediated, in part, by differential levels of activation in the anterior portions of the brain.

Supported by NIMH RO3 MH55513-01.

Van Landuyt, L.M., Ekkekakis, P., Hall, E.E., & Petruzzello, S.J., University of Illinois

Researchers have proposed that exercise must exceed a relatively high threshold of intensity (>60% VO₂ max) and duration (> 20-min) to produce positive affective changes, despite equivocal findings. The present investigations examined the effects of 10-minute walks, at a self-selected pace, in ecologically valid conditions on affect using multiple self-report measures. In study 1, 52 undergraduate volunteers were randomly assigned to either a walking group (n = 26) or a reading control group. Before and after each condition, the participants completed a battery of questionnaires including the Feeling Scale, the State Anxiety Inventory (SAI), the Activation Deactivation Adjective Checklist (AD-ACL), and the Positive And Negative Affect Schedule. Analysis indicated that, under these conditions, a short walk, in contrast to the control condition, was associated with more positive affective valence and increased activation. These findings were essentially replicated in Study 2 where 135 volunteers (76 exercise, 59 control) underwent the same treatments, and completed the AD-ACL and the SAI before, immediately after, and 10-min after treatment. The effects of the walk dissipated by the 10th minute post-walk. In conclusion, a brief outdoor walk was found to be effective in improving overall affect, specifically leading to a more activated pleasant affective state. Thus, the notion of a minimal threshold of exercise intensity/duration for affective change needs to be reconsidered.

Ekkekakis, P., Hall, E.E., & Petruzzello, S.J., University of Illinois

The SAI (Spielberger, 1983) has been criticized for exhibiting reduced internal consistency in the context of acute aerobic exercise and for confounding activation with affective valence, producing potentially invalid total state anxiety scores during and post-exercise. Two studies evaluated the psychometric properties of the SAI under such conditions. In Study 1, 45 female undergraduate volunteers participated in a 50-min session of aerobics at an intensity of 59% HRmax reserve. They completed an 8-item version of the SAI before, 25-min into, and immediately following the exercise bout. During exercise, coefficient alpha and mean inter-item correlation were reduced (.71 from .87 pre and .23 from .46 pre, respectively). Although the total SAI score remained unchanged from pre to during exercise, 2 items increased and 4 decreased. A measure of activation (Svebak & Murgatroyd, 1985) accounted for 7% (p<.05) of variance in total SAI score during and 26% (p<.001) following the exercise bout, beyond the variance accounted for by a measure of valence (38% and 16%, respectively). In Study 2, 69 undergraduate volunteers completed a 10-item version of the SAI before and after running on a treadmill for 30 min at 75% VO₂max. The total SAI score was increased (p<.001). Of the items, 5 indicative of activation showed increases, but 2 indicative of apprehension showed decreases. Internal consistency was again reduced. Concurrent assessment of Energetic Arousal (positively valent activation) also showed a significant increase. These findings indicate that the reliability and validity of the SAI as a measure of state anxiety are severely compromised in the context of acute exercise.

Hall, E.E., Ekkekakis, P., Van Landuyt, L.M., & Petruzzello, S.J., University of Illinois

Previous research has reliably documented that resting EEG frontal asymmetry (greater left frontal activation, relative to right) is a significant predictor of positive affective responses to aerobic exercise performed for 30 minutes at intensities at or above 70% of VO2max. The purpose of the present investigation was to examine the relationship between frontal asymmetry and affective responsivity using a short and non-vigorous bout of physical activity, namely a 10-min walk. To this end, regional brain activation was measured via EEG (F3, F4, referenced to linked-ears) in 42 volunteers prior to walking on a treadmill at a self-selected pace (speed = 2.76±.9 m.hr^-1, end HR = 99.3±19 b.min^-1) for 10-min. Affective responses were assessed via a 10-item version of Spielberger’s State Anxiety Inventory and Thayer’s AD-ACL, which yields measures of Energetic Arousal and Tense Arousal. The self-report scales were administered prior to, immediately following, and 10-min following the walk. Hierarchical regression analyses revealed that, in contrast to previous findings involving more vigorous exercise, resting frontal asymmetry, after partialling out pre-exercise affect, was unable to account for significant, unique variance in post-walk affect. This finding is consistent with a conceptual model, whereby frontal asymmetry, as a biological marker of approach motivation, is a significant predictor of affective responses only to doses of exercise that are high enough to present a significant challenge to the individual.