Aerobic Exercise Training and Inducible Inflammation: Results of a Randomized Controlled Trial in Healthy, Young Adults.

Background Consensus panels regularly recommend aerobic exercise for its health-promoting properties, due in part to presumed anti-inflammatory effects, but many studies show no such effect, possibly related to study differences in participants, interventions, inflammatory markers, and statistical approaches. This variability makes an unequivocal determination of the anti-inflammatory effects of aerobic training elusive. Methods and Results We conducted a randomized controlled trial of 12 weeks of aerobic exercise training or a wait list control condition followed by 4 weeks of sedentary deconditioning on lipopolysaccharide (0, 0.1, and 1.0 ng/mL)-inducible tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and on toll-like receptor 4 in 119 healthy, sedentary young adults. Aerobic capacity by cardiopulmonary exercise testing was measured at study entry (T1) and after training (T2) and deconditioning (T3). Despite a 15% increase in maximal oxygen consumption, there were no changes in inflammatory markers. Additional analyses revealed a differential longitudinal aerobic exercise training effect by lipopolysaccharide level in inducible TNF -α ( P=0.08) and IL-6 ( P=0.011), showing T1 to T2 increases rather than decreases in inducible (lipopolysaccharide 0.1, 1.0 versus 0.0 ng/mL) TNF- α (51% increase, P=0.041) and IL-6 (42% increase, P=0.11), and significant T2 to T3 decreases in inducible TNF- α (54% decrease, P=0.007) and IL-6 (55% decrease, P<0.001). There were no significant changes in either group at the 0.0 ng/mL lipopolysaccharide level for TNF- α or IL-6. Conclusions The failure to support the primary hypotheses and the unexpected post hoc findings of an exercise-training-induced proinflammatory response raise questions about whether and under what conditions exercise training has anti-inflammatory effects. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 01335737.

The Association of Cigarette Smoking With High-Frequency Heart Rate Variability: An Ecological Momentary Assessment Study.

OBJECTIVE: Evidence from both laboratory and observational studies suggests that acute and chronic smoking leads to reduced high-frequency heart rate variability (HF-HRV), a measure of cardiac vagal regulation. We used ecological momentary assessment (EMA) to study the effect of smoking on concurrent HF-HRV in a trial measuring the effects of hostility reduction and compared 24-hour HF-HRV in smokers and nonsmokers. METHOD: Ambulatory electrocardiogram data were collected before randomization from 149 healthy individuals with high hostility levels (20-45 years, body mass index ≤ 32 kg/m) and paired with concurrent EMA ratings of smoking and physical position during waking hours. A multilevel mixed model was estimated associating ln(HF-HRV) from smoking status (between-person factor) and person-centered momentary smoking (within-person factor, treated as a random effect), adjusting for momentary physical position, medication use, and consumption of alcohol and caffeine. RESULTS: Thirty-five smokers and 114 nonsmokers provided both EMA and HF-HRV data. Within smokers, ln HF-HRV was reduced by 0.31 millisecond (p = .04) when participants reported having recently smoked cigarettes, compared with when they had not. The 24-hour HF-HRV was significantly lower in smokers (M [SD] = 5.24 [0.14] milliseconds) than nonsmokers (5.63 ± 0.07 milliseconds, p = .01). CONCLUSIONS: In healthy smokers with high hostility levels used as their own controls during daily living, smoking acutely reduced HF-HRV. HF-HRV was also reduced in smokers as compared with nonsmokers. Although limited by a small sample of individuals with high hostility levels, these findings nonetheless provide additional evidence that cardiac vagal regulation is lowered by cigarette smoking, which may be one of the numerous pathophysiological effects of smoking.

Vagally-mediated heart rate variability and indices of well-being: Results of a nationally representative study.

OBJECTIVE: High frequency (HF) heart rate variability (HRV) has long been accepted as an index of cardiac vagal control. Recent studies report relationships between HF-HRV and indices of positive and negative affect, personality traits and well-being but these studies generally are based on small and selective samples. METHOD: These relationships were examined using data from 967 participants in the second Midlife in the U.S. (MIDUS II) study. Participants completed survey questionnaires on well-being and affect. HF-HRV was measured at rest. A hierarchical series of regression analyses examined relationships between these various indices and HF-HRV before and after adjustment for relevant demographic and biomedical factors. RESULTS: Significant inverse relationships were found only between indices of negative affect and HF-HRV. Relationships between indices of psychological and hedonic well-being and positive affect failed to reach significance. CONCLUSIONS: These findings raise questions about relationships between cardiac parasympathetic modulation, emotion regulation, and indices of well-being. (PsycINFO Database Record

The Effect of Hostility Reduction on Autonomic Control of the Heart and Vasculature: A Randomized Controlled Trial.

OBJECTIVE: Hostility is associated with coronary artery disease. One candidate mechanism may be autonomic nervous system (ANS) dysregulation. In this study, we report the effect of cognitive behavioral treatment on ANS regulation. METHODS: Participants were 158 healthy young adults, high in hostility measured by the Cook-Medley Hostility and Spielberger Trait Anger scales. Participants were also interviewed using the Interpersonal Hostility Assessment Technique. They were randomized to a 12-week cognitive behavioral treatment program for reducing hostility or a wait-list control group. The outcome measures were preejection period, low-frequency blood pressure variability, and high-frequency heart rate variability measured at rest and in response to and recovery from cognitive and orthostatic challenge. Linear-mixed models were used to examine group by session and group by session by period interactions while controlling for sex and age. Contrasts of differential group and session effects were used to examine reactivity and recovery from challenge. RESULTS: After Bonferroni correction, two-way and three-way interactions failed to achieve significance for preejection period, low-frequency blood pressure variability, or high-frequency heart rate variability (p > .002), indicating that hostility reduction treatment failed to influence ANS indices. CONCLUSIONS: Reduction in anger and hostility failed to alter ANS activity at rest or in response to or recovery from challenge. These findings raise questions about whether autonomic dysregulation represents a pathophysiological link between hostility and heart disease.

Linking Daily Stress Processes and Laboratory-Based Heart Rate Variability in a National Sample of Midlife and Older Adults.

OBJECTIVE: This study evaluates the associations between people's trait-like patterns of stress in daily life (stressor frequency, perceived stressor severity, affective reactivity to stressors, and negative affect) and laboratory-assessed heart rate variability (HRV). METHODS: Data were collected from 909 participants aged 35 to 85 years in the Midlife in the United States Study. Participants reported negative affect and minor stressful events during telephone interviews on 8 consecutive evenings. On a separate occasion, HRV was measured from electrocardiograph recordings taken at rest during a laboratory-based psychophysiology protocol. Regression models were used to evaluate the associations between daily stress processes and three log-transformed HRV indices: standard deviation of R-R intervals (SDRR), root mean square of successive differences (RMSSD), and high-frequency power (high-frequency HRV [HF-HRV]). Analyses were adjusted for demographics, body mass index, comorbid conditions, medications, physical activity, and smoking. RESULTS: Stressor frequency was unrelated to HRV (r values ranging from -0.04 to -0.01, p values >.20). However, people with greater perceived stressor severity had lower resting SDRR (fully adjusted B [standard error {SE}] = -0.05 [0.02]), RMSSD (-0.08 [0.03]), and HF-HRV (-0.16 [0.07]). Individuals with more pronounced affective reactivity to stressors also had lower levels of all three HRV indices (SDRR: B [SE] = -0.28 [0.14]; RMSSD: -0.44 [0.19]; HF-HRV: -0.96 [0.37]). Furthermore, aggregated daily negative affect was linked to reduced RMSSD (B [SE] = -0.16 [0.08]) and HF-HRV (-0.35 [0.15]). CONCLUSIONS: In a national sample, individual differences in daily negative affect and responses to daily stressors were more strongly related to cardiovascular autonomic regulation than the frequency of such stressors.

Vagal Recovery From Cognitive Challenge Moderates Age-Related Deficits in Executive Functioning.

Decline in executive functioning (EF) is a hallmark of cognitive aging. We have previously reported that faster vagal recovery from cognitive challenge is associated with better EF. This study examined the association between vagal recovery from cognitive challenge and age-related differences in EF among 817 participants in the Midlife in the U.S. study (aged 35-86). Cardiac vagal control was measured as high-frequency heart rate variability. Vagal recovery moderated the association between age and EF (ß = .811, p = .004). Secondary analyses revealed that older participants (aged 65-86) with faster vagal recovery had superior EF compared to their peers who had slower vagal recovery. In contrast, among younger (aged 35-54) and middle-aged (aged 55-64) participants, vagal recovery was not associated with EF. We conclude that faster vagal recovery from cognitive challenge is associated with reduced deficits in EF among older, but not younger individuals.

A longitudinal study of depression, fatigue, and sleep disturbances as a symptom cluster in women with breast cancer.

CONTEXT: Depression, fatigue, and sleep disturbances have been identified as a symptom cluster among breast cancer patients. However, few longitudinal studies have examined the temporal relations between these symptoms surrounding diagnosis and treatment. OBJECTIVES: The present study investigated the co-occurrence of and interrelations between nonsomatic depressive symptoms, fatigue, and sleep disturbances in breast cancer patients at three time points: before, after, and six to eight months following adjuvant chemotherapy treatment. METHODS: Separate samples of premenopausal (n = 67) and postmenopausal (n = 67) breast cancer patients completed self-report measures of depression, fatigue, and sleep disturbances at all three time points. Path analysis was used to explore within- and cross-symptom paths across time. RESULTS: Depression, fatigue, and sleep disturbances were correlated within each time point. Continuity paths, whereby prior levels of symptom severity tended to predict subsequent severity of the same symptom at the subsequent time point, were significant in both samples, except for depression in the premenopausal sample. Instead, significant cross-symptom paths emerged whereby baseline fatigue predicted postchemotherapy depression, and postchemotherapy fatigue predicted depression at follow-up in the premenopausal patients. No significant cross-symptom paths emerged for the postmenopausal sample. CONCLUSION: Findings supported the notion that depression, fatigue, and sleep disturbances manifest as a symptom cluster. Fatigue may precede nonsomatic symptoms of depression among premenopausal breast cancer patients and represents a potential intervention target.

Heart rate variability predicts levels of inflammatory markers: Evidence for the vagal anti-inflammatory pathway.

Evidence from numerous animal models shows that vagal activity regulates inflammatory responses by decreasing cytokine release. Heart rate variability (HRV) is a reliable index of cardiac vagal regulation and should be inversely related to levels of inflammatory markers. Inflammation is also regulated by sympathetic inputs, but only one previous paper controlled for this. In a larger and more representative sample, we sought to replicate those results and examine potential sex differences in the relationship between HRV and inflammatory markers. Using data from the MIDUS II study, we analyzed the relationship between 6 inflammatory markers and both HF-HRV and LF-HRV. After controlling for sympathetic effects measured by urinary norepinephrine as well as a host of other factors, LF-HRV was found to be inversely associated with fibrinogen, CRP and IL-6, while HF-HRV was inversely associated with fibrinogen and CRP. We did not observe consistent sex differences. These results support the existence of the vagal anti-inflammatory pathway and suggest that it has similar effects in men and women.

Race differences in age-trends of autonomic nervous system functioning.

OBJECTIVE: The objective of this study was to consider race differences in age-trends of autonomic nervous system functioning, using a national data set with a broad age range. METHODS: Measures of baseline heart rate variability (HRV) and HRV reactivity were derived from electrocardiograph (ECG) recordings taken at rest and during cognitive stress tasks. Age-trends in HRV and HRV reactivity were compared among 204 African Americans and 833 Whites ages 34 to 83 years (M = 53.7, SD = 11.4), before and after controlling for socioeconomic status (SES). RESULTS: For HRV-reactivity, age-trends were steeper among African Americans and lower SES participants than Whites and higher SES participants. For baseline HRV, age-trends varied by SES but not race. DISCUSSION: Results relating to HRV-reactivity (but not baseline HRV) were consistent with hypotheses suggesting that African Americans are exposed to higher levels of stress and experience accelerated declines in health across the life span. The relevance of the findings to research on social stress and health disparities is discussed.

Aerobic exercise and strength training effects on cardiovascular sympathetic function in healthy adults: a randomized controlled trial.

OBJECTIVE: Exercise has widely documented cardioprotective effects, but the mechanisms underlying these effects are not entirely known. Previously, we demonstrated that aerobic but not strength training lowered resting heart rate and increased cardiac vagal regulation, changes that were reversed by sedentary deconditioning. Here, we focus on the sympathetic nervous system and test whether aerobic training lowers levels of cardiovascular sympathetic activity in rest and that deconditioning would reverse this effect. METHODS: We conducted a randomized controlled trial contrasting the effects of aerobic (A) versus strength (S) training on indices of cardiac (preejection period, or PEP) and vascular (low-frequency blood pressure variability, or LF BPV) sympathetic regulation in 149 young, healthy, and sedentary adults. Participants were studied before and after conditioning, as well as after 4 weeks of sedentary deconditioning. RESULTS: As previously reported, aerobic capacity increased in response to conditioning and decreased after deconditioning in the aerobic, but not the strength, training group. Contrary to prediction, there was no differential effect of training on either PEP (A: mean [SD] -0.83 [7.8] milliseconds versus S: 1.47 [6.69] milliseconds) or LF BPV (A: mean [SD] -0.09 [0.93] ln mm Hg(2) versus S: 0.06 [0.79] ln mm Hg(2)) (both p values > .05). CONCLUSIONS: These findings, from a large randomized controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on resting state cardiovascular indices of PEP and LF BPV. These results indicate that in healthy, young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in resting sympathetic activity. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT00358137.

A pilot randomized controlled trial of a commercial diet and exercise weight loss program in minority breast cancer survivors.

OBJECTIVE: Obesity is associated with poorer breast cancer outcomes and losing weight postdiagnosis may improve survival. As Hispanic and black women have poorer breast cancer prognosis than non-Hispanic whites diagnosed at similar age and stage, and have higher rates of obesity, effective weight loss strategies are needed. We piloted a randomized, waitlist-controlled, crossover study to examine the effects and feasibility of the commercial Curves weight loss program among Hispanic, African American and Afro-Caribbean breast cancer survivors. DESIGN AND METHODS: Women with stage 0-IIIa breast cancer ≥ 6 months posttreatment, sedentary, and BMI ≥ 25 kg/m(2) were randomized to the immediate arm (IA): 6 months of the Curves program followed by 6 months of observation; or the waitlist control arm (WCA): 6 months of observation followed by 6 months of the Curves program. The Curves program uses a 30-min exercise circuit and a high-vegetable/low-fat/calorie-restricted diet. RESULTS: A total of 42 women enrolled (79% Hispanic, 21% black), mean age 51 (range 32-69) and mean BMI 33.2(± 5.9) kg/m(2); 91% were retained at month 12. At month 6, women in the IA lost an average 3.3% (± 3.5%) of body weight (range: 1.7% gain to 10.6% loss), as compared with 1.8% (± 2.9%) weight loss in the WCA (P = 0.04). At month 12, on average women in the IA regained some but not all of the weight lost during the first 6 months (P = 0.02). CONCLUSIONS: Minority breast cancer survivors were recruited and retained in a weight loss study. Six months of the Curves program resulted in moderate weight loss, but weight loss was not maintained postintervention. Future interventions should identify methods to increase uptake and maintenance of weight loss behaviors.

The interactive effect of change in perceived stress and trait anxiety on vagal recovery from cognitive challenge.

The present study tested the hypothesis that the change in state negative affect (measured as perceived stress) after cognitive challenge moderates the relationship of trait anxiety and anger to vagal recovery from that challenge. Cardiac vagal control (assessed using heart rate variability) and respiratory rate were measured in a sample of 905 participants from the Midlife in the United States Study. Cognitive challenges consisted of computerized mental arithmetic and Stroop color-word matching tasks. Multiple regression analyses controlling for the effects of the demographic, lifestyle, and medical factors influencing cardiac vagal control showed a significant moderating effect of change in perceived stress on the relationship of trait anxiety to vagal recovery from cognitive challenges (Beta=.253, p=.013). After adjustment for respiratory rate, this effect became marginally significant (Beta=.177, p=.037). In contrast, for the relationship of trait anger to vagal recovery, this effect was not significant either before (Beta=.141, p=.257) or after (Beta=.186, p=.072) adjusting for respiratory rate. Secondary analyses revealed that among the individuals with higher levels of trait anxiety, greater reductions in perceived stress were associated with greater increases in cardiac vagal control after the challenge. In contrast, among the individuals with lower levels of trait anxiety, changes in perceived stress had no impact on vagal recovery. Therefore, change in perceived stress moderates the relationship of trait anxiety, but not trait anger, to vagal recovery from cognitive challenge.

Impact of aerobic training on cardiovascular reactivity to and recovery from challenge.

OBJECTIVE: To test the hypothesis that aerobic, but not strength, training would lead to attenuated reactivity to and more rapid recovery from cognitive and orthostatic challenge and that deconditioning would reverse this effect. METHODS: We conducted a randomized controlled trial contrasting the effects of aerobic versus strength training on heart rate, four indices of RR interval variability, and blood pressure reactivity to and recovery from psychological and orthostatic challenge in 149 healthy, young, sedentary adults. Subjects were randomized to 12-week aerobic or strength training programs and studied before and after training and again after 4 weeks of sedentary deconditioning. The data were analyzed by performing a Group (aerobic versus strength) by Session (study entry, post training, and deconditioning), by Period (baseline, speech, Stroop, math, tilt) three-way analysis of variance with prespecified contrasts of the effect of group assignment on reactivity and recovery. RESULTS: Aerobic capacity increased in response to conditioning and decreased after deconditioning in the aerobic, but not the strength, training group. However, the two groups did not differ on heart rate, RR interval variability, or blood pressure reactivity to or recovery from laboratory challenge. CONCLUSIONS: These findings, from the largest randomized controlled trial to address this matter to date, raise doubts about attenuation of reactivity or enhancement of recovery as a putative mechanism underlying the cardioprotective effects of aerobic exercise. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00365196.

Heart rate recovery after cognitive challenge is preserved with age.

OBJECTIVE: To investigate the effect of age on heart rate recovery (HRR) from cognitive challenge. BACKGROUND: Aging is an independent risk factor for the development of cardiovascular disease. HRR from exercise is an established predictor of cardiac morbidity and mortality, and evidence suggests that HRR from cognitive challenge is predictive of cardiac morbidity as well. Aging is associated with delayed HRR from exercise stress, but little is known about the effect of aging on HRR from psychological stress. We tested the hypothesis that age would be related to delayed HRR from psychological stress. METHODS: HRR post exposure to cognitive challenge (mental arithmetic and Stroop) was investigated in a sample of 436 participants aged 35 to 84 years in MIDUS II, a national study of health and well-being. HRR was measured as 1) the amount of change from the stress level; 2) time to recover; and 3) the area under the curve. The analyses were controlled for medical comorbidities and medications that influence HR, such as body mass index, smoking, sex, menopausal status, and amount of physical activity/exercise. RESULTS: There was no effect for age on HRR as evaluated by all three recovery assessment methods. CONCLUSIONS: Contrary to expectation and in contrast to findings concerning HRR from exercise, HRR from cognitive challenge was preserved with age. These findings require further inquiry into differential mechanism(s) underlying HRR from psychological versus exercise stress, including any role for improved emotion regulation with greater age.

Cardiac autonomic control and treatment of hostility: a randomized controlled trial.

OBJECTIVE: To test whether reduction in hostility increases autonomic regulation of the heart. METHODS: In this randomized controlled trial, participants were 158 healthy adults, aged 20 years to 45 years, who were 1 standard deviation (SD) above national norms on the Cook-Medley Hostility and the Spielberger Trait Anger Indices. Participants also were interviewed, using the Interpersonal Hostility Assessment Technique (IHAT). They were randomly assigned to a 12-week cognitive behavior therapy program for hostility reduction or a wait-list control condition. The main outcome measure was cardiac autonomic modulation, measured as RR interval variability (RRV) derived from 24-electrocardiographic recordings. RESULTS: In a multivariate analysis of variance assessing psychological outcomes of hostility, anger, and IHAT scores, there was a significant treatment effect with an average reduction across the three outcomes that was approximately 0.7 SD (ES = 0.685, SE = 0.184, p < .001) greater for the intervention group than for the control group. In contrast, the change in heart rate was -0.14 beat/min (95% Confidence Interval [CI] = -2.43, 2.14) in treatment participants and -1.36 beat/min (95% CI = -3.28, 0.61) in wait-list participants. High-frequency RRV, an index of cardiac parasympathetic modulation, increased by 0.07 ln ms(2) (95% CI = -0.10, 0.24) for participants in the treatment condition and decreased by 0.04 ln ms(2) (95% CI = -0.18, 0.10) for participants in the wait-list condition. These differences were not significant. The findings for other indices of RRV were similar. CONCLUSIONS: Reduction of hostility and anger was not accompanied by increases in cardiac autonomic modulation. These findings raise questions about the status of disordered autonomic nervous system regulation of the heart as a pathophysiological mechanism underlying the hostility-heart disease relationship and about whether hostility itself is a mechanism or merely a marker of elevated risk of heart disease.

The cognitive effects of chemotherapy in post-menopausal breast cancer patients: a controlled longitudinal study.

Studies suggest that adjuvant chemotherapy for early stage breast cancer (BC) is associated with cognitive impairment related to attention, memory, and visuospatial functioning. However, other studies have failed to confirm that relationship. We report one of the first longitudinal, controlled studies of cognitive effects of chemotherapy in older post-menopausal women. Sixty-one post-menopausal women with non-metastatic BC were administered neuropsychological tests before adjuvant therapy (Time1), six months after treatment (Time2), and at a final 6-month follow-up (Time3). Thirty women were treated with chemotherapy; thirty-one women who received no chemotherapy were controls. Cognitive domains measured included motor, language, attention/concentration/working memory, visuospatial, and memory (verbal and visual). Time-by-treatment interaction was significant in the motor domain (P = 0.007) with poorer performance in women treated with chemotherapy. For the other domains, scores did not significantly vary over time by group. In post-menopausal women, chemotherapy was not associated with changes in cognitive function in areas reported by BC survivors: attention, memory, and information processing. Motor slowing in women treated with chemotherapy could be secondary to peripheral neuropathy rather than an indication of more general declines in cognitive processing. Future studies should control for the independent effects of slowed motor functioning when looking to study possible chemotherapy related cognitive processing deficits.

The impact of menstrual cycle phase on cardiac autonomic regulation.

This study investigated menstrual cycle phase differences in heart rate (HR) and RR interval variability (RRV) in 49 healthy, premenopausal, eumenorrheic women (age 30.2+/-6.2 years). HR and RRV were computed from ambulatory 24-h electrocardiogram, collected for up to 6 days, with at least 1 day each during early to midfollicular and midluteal menstrual phases. Phase effects on HR and RRV were assessed using linear mixed effects models with a random intercept to account for the correlation of observations within each subject as well as intrasubject variation. During follicular phase monitoring, women had significantly lower average HR (-2.33 bpm), and higher standard deviation, the root mean squared successive difference, and high frequency (0.04-0.15 Hz) and low frequency (0.15-0.40 Hz) RRV than during the luteal phase. These results provide strong support for the influence of menstrual phase on cardiac autonomic regulation in premenopausal women.

The effect of aerobic training and cardiac autonomic regulation in young adults.

OBJECTIVES: We tested the effect of aerobic exercise on autonomic regulation of the heart in healthy young adults. METHODS: Healthy, sedentary young adults (n = 149; age = 30.4 +/- 7.53 years) were randomized to receive 12 weeks of either aerobic conditioning or strength training. Primary outcomes were heart rate and RR interval variability (RRV) measured before and after training and after 4 weeks of sedentary deconditioning. RRV, a noninvasive index of cardiac autonomic regulation, reflects variability in the intervals between consecutive R waves of the electrocardiogram. RESULTS: Aerobic conditioning but not strength training led to a significant increase in aerobic capacity (3.11 mL/kg/min), a decrease in heart rate (-3.49 beats per minute), and an increase in high-frequency RRV (0.25 natural log msec2), each of which returned to pretraining levels after deconditioning. Significant 3-way interactions, however, revealed autonomic effects only in men. CONCLUSIONS: In sedentary, healthy young adults, aerobic conditioning but not strength training enhances autonomic control of the heart, but post hoc analyses suggested that gender plays a significant role in this exercise-related cardioprotection.

Aerobic exercise attenuates inducible TNF production in humans.

Aerobic exercise reduces coronary heart disease risk, but the mechanisms of this protection are not fully understood. Atherosclerosis is an inflammatory disease mediated by monocyte-derived macrophages, which accumulate in arterial plaques and become activated to release factors, including cytokines, that cause damage. Here we studied the effects of aerobic training on monocyte production of tumor necrosis factor (TNF) in whole blood ex vivo. Healthy young sedentary adults (n = 61, age 20-45 yr) were randomized to a moderate- (M) or a high- (H) intensity 12-wk training program. Whole blood was extracted before and after training, and then it was stimulated by addition of lipopolysaccharide (LPS); inducible TNF was measured in the plasma. Data were analyzed according to intention to treat principles using a random-effect model to determine the impact of training group on maximal aerobic capacity and LPS-stimulated TNF after correcting for covariates. Analyses revealed improvement in aerobic capacity in both the H (9%) and the M (7%) groups. However, aerobic training led to significant (P < 0.001) decreases in TNF release only in the H group. These data suggest that in healthy young adults, a 12-wk high-intensity aerobic training program downregulates blood monocyte production of stimulated cytokine release.

Cultural differences in conceptual models of everyday fatigue: a vignette study.

The present study used a qualitative methodology to examine cultural differences in representations of everyday fatigue. Thirty-seven European American women and 36 South Asian immigrant women responded to a vignette describing fatigue. A dimensional model of illness representation was used to develop a coding scheme and analyze the data. Results indicate both similarities and differences in conceptual models of fatigue. European Americans were more likely to medicalize fatigue symptoms and view them as acute, severe and in need of treatment. The social and familial context of women's everyday lives strongly influenced their representations.