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Chun-Chih Wang, Chien-Heng Chu, I-Hua Chu, Kuei-Hui Chan and Yu-Kai Chang

This study was designed to examine the modulation of executive functions during acute exercise and to determine whether exercise intensity moderates this relationship. Eighty college-aged adults were recruited and randomly assigned into one of the four following groups: control, 30%, 50%, and 80% heart rate reserve. The Wisconsin Card Sorting Test (WCST) was administered during each intervention. The results indicated that the majority of the WCST performances were impaired in the high exercise intensity group relative to those of the other three groups, whereas similar performance rates were maintained in the low- and moderate-intensity groups. These findings suggest that transient hypofrontality occurs during high-intensity exercise, but not during low- and moderate-intensity exercises. Future research aimed at employing the dual-mode theory, and applying the reticular-activating hypofrontality model is recommended to further the current knowledge.

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Shannon Bezoian, W. Jack Rejeski and Edward McAuley

The present study examined the role that preexisting efficacy cognitions played in the generation of exercise-induced feeling states during and following an acute bout of exercise. In so doing, the construct validity of a newly developed measure of psychological responses to exercise, the Exercise-Induced Feeling Inventory (EFI; Gauvin & Rejeski, 1993), was investigated. Female undergraduates, classified as having either high or low physical efficacy, engaged in an acute exercise bout and feeling states were recorded prior to, during, and following the activity. More efficacious females maintained a sense of energy during exercise and felt more revitalized and experienced increased positive engagement postexercise than did their less efficacious counterparts. Such findings provide further support for a social-cognitive interpretation of how psychological responses to physical activity might be generated. Results are further discussed in terms of the measurement of exercise-induced feeling states and future applications of the EFI.

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Keith Tolfrey, Alice Emily Thackray and Laura Ann Barrett

Exaggerated postprandial triacylglycerol concentrations (TAG) independently predict future cardiovascular events. Acute exercise and diet interventions attenuate postprandial TAG in adults. This paper aims to examine the exercise postprandial lipemia studies published to date in young people. Nine studies satisfied the inclusion criteria adopted for this summary. The majority of studies are in boys (22% girls) and have shown a single ~60-min session of moderate-intensity exercise, performed 12-18 hours before a standardized meal, reduces postprandial TAG. Manipulations of exercise duration and intensity suggest an exercise energy expenditure dose-dependent response is not supported directly in healthy young people. Studies investigating alternative exercise bouts have reported lower postprandial TAG after simulated intermittent games activity, high-intensity interval running and cumulative 10-min blocks over several hours, which may appeal to the spontaneous physical activity habits of young people. Although extension of these initial findings is warranted, exercise may be an effective strategy to promote regular benefits in TAG metabolism in children and adolescents; this may contribute to an improved cardiovascular disease risk profile early in life.

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Mia K. Newlin, Sara Williams, Tim McNamara, Harold Tjalsma, Dorine W. Swinkels and Emily M. Haymes

Purpose:

To investigate the effects of acute exercise on serum hepcidin and iron (sFe) in active women. Changes in interleukin-6 (IL-6), hepcidin, ferritin, and sFe in response to 2 different exercise durations were compared.

Methods:

Twelve women age 19–32 yr performed 2 treadmill runs (60 and 120 min) at 65% of VO2max. Blood samples were obtained before, immediately after, and 3, 6, 9, and 24 hr after exercise. Two-way repeatedmeasures ANOVA was conducted to examine changes in measured variables. Significance was accepted at p < .05.

Results:

Significant effects for trial were observed for hepcidin (60 min: 1.15 ± 0.48 nmol/L; 120 min: 2.28 ± 1.44 nmol/L) and for time, with hepcidin significantly increased 3 hr postexercise in both trials (60 min: 3 hr – 1.99 ± 2.00 nmol/L; 120 min: 3 hr – 4.60 ± 4.61 nmol/L). Significant main effects for time occurred for sFe, ferritin, and IL-6. sFe was significantly decreased 9 hr postexercise compared with 3 and 24 hr postexercise. IL-6 was significantly increased immediately postexercise.

Conclusions:

Both runs resulted in significant increases in hepcidin 3 hr after exercise. Increases in hepcidin were preceded by significant increases in IL-6 immediately postexercise and followed by significant decreases in sFe 9 hr postexercise. It was concluded that endurance exercise increases the production of hepcidin, which affects sFe. The 2-hr exercise bout stimulated greater changes in serum hepcidin than the 1-hr bout.

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Caterina Pesce and Michel Audiffren

This study investigated the effects of acute exercise on 53 young (16–24 years) and 47 older (65–74 years) adults’ switch-task performance. Participants practiced sports requiring either low or high cognitive demands. Both at rest and during aerobic exercise, the participants performed two reaction time tasks that differed in the amount of executive control involved in switching between global and local target features of visual compound stimuli. Switch costs were computed as reaction time differences between switch and nonswitch trials. In the low demanding task, switch costs were sensitive only to age, whereas in the high demanding task, they were sensitive to acute exercise, age, and sport-related cognitive expertise. The results suggest that acute exercise enhances cognitive flexibility and facilitates complex switch-task performance. Both young age and habitual practice of cognitively challenging sports are associated with smaller switch costs, but neither age nor cognitive expertise seem to moderate the relationship between acute exercise and switch-task performance.

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Richard J. Bloomer, Bradford Cole and Kelsey H. Fisher-Wellman

High-kilocalorie feedings induce oxidative stress. Acute exercise has the potential to attenuate postprandial oxidative stress. No study has determined whether there are racial differences in postprandial oxidative stress with and without a preceding bout of acute exercise.

Purpose:

To investigate the impact of acute exercise on blood oxidative- stress biomarkers, triglycerides (TAG), and glucose in African American (AA) and White (W) women.

Methods:

10 AA (age 29 ± 3 yr, body-mass index [BMI] 31 ± 3 kg/m2) and 10 W (age 30 ± 2 yr, BMI 30 ± 3 kg/m2) women consumed a meal of 1.2 g of fat and carbohydrate and 0.25 g of protein per kilogram body mass, on 2 occasions—with and without a session of aerobic exercise 15 min preceding the meal (45 min cycling at 65% heart-rate reserve)—in a random-order crossover design. Blood samples were collected premeal (fasted), and at 1, 2, 4, and 6 hr postmeal and assayed for TAG, glucose, xanthine oxidase activity, hydrogen peroxide (H2O2), and malondialdehyde (MDA). Area under the curve (AUC) was calculated for each variable.

Results:

AUC was lower for AA compared with W for both the exercise and the no exercise conditions for H2O2, MDA, and TAG (p < .01). However, acute exercise had no effect on decreasing the AUC for any variable in either AA or W women (p > .05).

Conclusions:

Postprandial lipemia and oxidative stress are lower in AA than in W overweight/obese women. However, acute exercise, performed at the intensity and duration in the current study, does not influence postprandial lipemia or oxidative stress in AA or W women.

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Kent C. Hansen and Dale A. Schoeller

Objective:

Increasing fat content in an isocaloric diet is associated with positive fat imbalance. Exercise attenuates this process, and the authors hypothesized the attenuation was a result of altered postprandial lipid trafficking.

Design:

To investigate the effects of prior exercise and nutritional state on the metabolic fate of dietary fat, a study was designed with 4 treatment arms. Energy-balance modifications (fed or fasted) ± exercise were followed by postexercise feeding of 1-14C oleic acid to Sprague-Dawley rats. Fed rats were fed 6 hr before treatment, whereas fasted rats were fasted for 15 hr before treatment with the primary variable being exercise.

Measurements:

14C content of gastrointestinal tract, plasma, breath, muscle (soleus, vastus lateralis [VL], and extensor digitorum longus), liver, and adipose tissue (retroperitoneal and epididymal) was measured at 5 time points postdose (1, 2, 4, 8, and 24 hr).

Results:

Compared with matched unexercised controls, fed rats undergoing acute exercise significantly increased recovery of 14C in breath (p = .005) and plasma (p = .001), and trends of increasing 14C recovery occurred in VL (p = .07) and soleus (p = .06). Acute exercise significantly increased recovery of 14C in breath (p = .003), VL (p = .04), and soleus (p = .03) in the fasted study. Acute exercise significantly decreased the trafficking of dietary tracer into adipose tissue in only the fed study (p < .0001).

Conclusion:

Although the effect of acute exercise on trafficking dietary fat away from adipose tissue was greater in the fed group than in the fasted, acute exercise had beneficial effects on adipose tissue’s collecting dietary fat when fed or fasted.

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Jaak Jürimäe

Physical exercise is known to regulate energy balance. Important to this regulatory system is the existence of several peptides that communicate the status of body energy stores to the brain and are related to the body fatness including leptin, adiponectin and ghrelin. These hormones assist in regulating energy balance as well as somatic and pubertal growth in children. It appears that rather few studies have investigated the responses of leptin, adiponectin and ghrelin to acute exercise and these studies have demonstrated no changes in these peptides as a result of exercise. Leptin levels are decreased and may remain unchanged advancing from prepuberty to pubertal maturation in young male and female athletes. A limited number of studies indicate that adiponectin levels are not different between prepubertal and pubertal athletes and untrained controls. However, in certain circumstances circulating adiponectin could be increased in young athletes after onset of puberty as a result of heavily increased energy expenditure. Ghrelin levels are elevated in young sportsmen. However, pubertal onset decreases ghrelin levels in boys and girls even in the presence of chronically elevated energy expenditure as seen in young athletes. Ghrelin may also be used as an indicator of energy imbalance across the menstrual cycle in adolescent athletes. There are no studies with high-molecular-weight adiponectin and only very few studies with acylated ghrelin responses to acute exercise and chronic training have been performed in young athletes. Since these forms of adiponectin and ghrelin have been thought to be bioactive forms, further studies with these specific forms of adiponectin and ghrelin are needed. In conclusion, further studies should be conducted to investigate the response of these hormones to acute and chronic negative energy balance to better understand their role in regulating energy balance during growth and maturation in young athletes.

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Brian C. Focht and Heather A. Hausenblas

This study examined the state anxiety (SA) and perceived arousal (AS) responses to self-selected or imposed-intensity bouts of acute exercise performed in different environments by 30 women with high social physique anxiety (SPA). Participants were randomly assigned to a self-selected or imposed-intensity choice group and subsequently (a) exercised in a naturalistic environment, (b) exercised in a laboratory environment, and (c) rested quietly. Assessments of SA and AS were obtained before, during, and following each condition and data were analyzed via separate 2 × 3 × 6 (Intensity Choice × Condition × Time) ANOVAs with repeated measures on the Condition and Time factors. Results revealed that AS increased during both exercise conditions. Conversely, SA was elevated only during the naturalistic exercise condition, and item-level analysis revealed that this increase was composed of both activation and apprehension/worry inventory items. Although SA was reduced 5 min following both exercise conditions, the anxiolytic effect only persisted following the laboratory condition. No significant differences in SA or AS were observed between the two groups. It is concluded that environmentally-induced perceived evaluative threat is associated with an increase in SA during exercise and may attenuate postexercise anxiolysis in women with high SPA.

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Jennifer L. Etnier, Laurie Wideman, Jeffrey D. Labban, Aaron T. Piepmeier, Daniel M. Pendleton, Kelly K. Dvorak and Katie Becofsky

Acute exercise benefits cognition, and some evidence suggests that brain-derived neurotrophic factor (BDNF) plays a role in this effect. The purpose of this study was to explore the dose–response relationship between exercise intensity, memory, and BDNF. Young adults completed 3 exercise sessions at different intensities relative to ventilator threshold (Vt) (VO2max, Vt – 20%, Vt + 20%). For each session, participants exercised for approximately 30 min. Following exercise, they performed the Rey Auditory Verbal Learning Test (RAVLT) to assess short-term memory, learning, and long-term memory recall. Twenty-four hours later, they completed the RAVLT recognition trial, which provided another measure of long-term memory. Blood was drawn before exercise, immediately postexercise, and after the 30-min recall test. Results indicated that long-term memory as assessed after the 24-hr delay differed as a function of exercise intensity with the largest benefits observed following maximal intensity exercise. BDNF data showed a significant increase in response to exercise; however, there were no differences relative to exercise intensity and there were no significant associations between BDNF and memory. Future research is warranted so that we can better understand how to use exercise to benefit cognitive performance.