Biomedical subjects

Panteleimon Ekkekakis

Publications and source records attributed to Panteleimon Ekkekakis.

7 recordsLinked to original sources

PubMed2006

Can self-reported preference for exercise intensity predict physiologically defined self-selected exercise intensity?

Exercise prescription guidelines emphasize the importance of individual preferences for different intensities, but such preferences have not been studied systematically. This study examined the hypothesis that the preference scale of the Preference for and Tolerance of the Intensity of Exercise Questionnaire would predict self-selected exercise intensity. Twenty-three previously sedentary middle-aged women participated in a treadmill test and a 20-min session at a self-selected intensity. After controlling for age, body mass index, and peak oxygen uptake, the preference scale accounted for significant portions of the variance in the percentage of oxygen uptake associated with the ventilatory threshold at Minute 15 and Minute 20 of the session at self-selected intensity.

Adult↗

PubMed2006

Sleep duration and overweight among Australian children and adolescents.

AIM: To examine the association between sleep and overweight and waist circumference (WC) in children and adolescents. METHODS: Data were from a nationally representative sample of 6324 7-15-y-old males and females from the Australian Health and Fitness Survey. Associations between sleep duration and body mass index (BMI) and WC were examined by analysis of covariance, linear regression, and logistic regression. RESULTS: In the total sample, there was a significant main effect across sleep-duration categories ( or=10 h) for BMI. Linear regression showed significant age, sex, age-sleep, and age-sex-sleep interactions in the total sample. There was an inverse graded relationship between sleep and BMI and WC in boys. In boys, there was a 1.6-1.8 times greater odds of overweight for those who reported 8-9 h or 9-10 h of sleep compared to those reporting>or=10 h of sleep. For boys reporting or=10 h of sleep. In contrast, no significant associations between sleep and overweight were found in girls. CONCLUSION: Sleep duration was inversely related with overweight in young males but not females.

Adolescent↗

PubMed2005

What intensity of physical activity do previously sedentary middle-aged women select? Evidence of a coherent pattern from physiological, perceptual, and affective markers.

BACKGROUND: The intensity of physical activity has been found to be inversely related to adherence, thus contributing to the problem of physical inactivity. Although most physical activity is unsupervised and participants, therefore, self-select the intensity, very little is known about the level of intensity that they select. We hypothesized that participants would select, on average, an intensity proximal to the level of transition from aerobic to anaerobic metabolism. METHODS: Twenty-three middle-aged, formerly sedentary women participated in (a) an incremental treadmill test to determine their maximal aerobic capacity and gas exchange ventilatory threshold, an index of the aerobic-anaerobic transition, and (b) a 20-min bout of treadmill exercise during which they were allowed to select the speed. RESULTS: On average, but with considerable interindividual variability, the women selected an intensity that, in terms of treadmill speed, heart rate, oxygen uptake, and perceived exertion was no different from the intensity corresponding to their gas exchange ventilatory threshold. Moreover, affective valence remained positive and stable. CONCLUSIONS: On average, middle-aged, formerly sedentary women selected an intensity that is considered physiologically effective and reported that it did not feel hard or unpleasant. Future research should examine the sources of interindividual variability and the consequences of exercising at an intensity that exceeds one's preferred level.

Adult↗

PubMed2005

Variation and homogeneity in affective responses to physical activity of varying intensities: an alternative perspective on dose-response based on evolutionary considerations.

A model for systematic changes in patterns of inter-individual variation in affective responses to physical activity of varying intensities is presented, as a conceptual alternative to the search for a global dose-response curve. It is theorized that trends towards universality will emerge in response to activities that are either generally adaptive, such as moderate walking, or generally maladaptive, such as strenuous running that requires anaerobic metabolism and precludes the maintenance of a physiological steady state. At the former intensity the dominant response will be pleasure, whereas at the latter intensity the dominant response will be displeasure. In contrast, affective responses will be highly variable, involving pleasure or displeasure, when the intensity of physical activity approximates the transition from aerobic to anaerobic metabolism, since activity performed at this intensity entails a trade-off between benefits and risks. Preliminary evidence in support of this model is presented, based on a reanalysis of data from a series of studies.

Adaptation, Physiological↗

PubMed2005

Is the relationship of RPE to psychological factors intensity-dependent?

PURPOSE: Although ample evidence shows that ratings of perceived exertion (RPE) are correlated with psychological variables, whether and how these relationships change as a function of exercise intensity remains unclear. The purpose of this study was to examine the correlations of RPE with both dispositional (extraversion, neuroticism, behavioral activation, behavioral inhibition) and situational (self-efficacy) psychological variables across three exercise intensities. Based on the social-psychophysiological model proposed by Rejeski, it was hypothesized that the correlations would be weakened as the intensity increased. METHODS: Thirty young and healthy volunteers participated in three 15-min treadmill runs, one 20% VO2max below, one at, and one 10% VO2max above the ventilatory threshold. RPE was assessed at minutes 3, 6, 9, 12, and 15. RESULTS: Extraversion, behavioral activation, and self-efficacy showed significant negative correlations with RPE at lower but not higher intensities, whereas neuroticism was unrelated to RPE and behavioral inhibition was positively related across all three levels of intensity. CONCLUSIONS: The results provide partial support to the hypothesis that the relationship of dispositional and situational psychological factors to RPE changes systematically, becoming weaker at higher exercise intensities. This may have implications for the effectiveness of personality-based adjustments of exercise prescriptions and cognitive techniques for dealing with aversive sensations of exertion.

Adult↗

PubMed2004

Practical markers of the transition from aerobic to anaerobic metabolism during exercise: rationale and a case for affect-based exercise prescription.

BACKGROUND: The high rates of dropout from exercise programs may be attributed in part to the poor ability of most individuals to accurately self-monitor and self-regulate their exercise intensity. The point of transition from aerobic to anaerobic metabolism may be an appropriate level of exercise training intensity as it appears to be effective and safe for a variety of populations. Possible practical markers of this event were compared. METHODS: Two samples of 30 young and healthy volunteers each participated in incremental treadmill tests until volitional exhaustion. The ventilatory threshold, a noninvasive estimate of the aerobic-anaerobic transition, was identified from gas exchange data. Heart rate, self-ratings of affective valence (pleasure-displeasure), perceived activation, and perceived exertion were recorded every minute. RESULTS: In both samples, heart rate, perceived activation, and perceived exertion rose continuously, whereas the ratings of affective valence showed a pattern of quadratic decline, initiated once the ventilatory threshold was exceeded. CONCLUSIONS: Exercise intensity that exceeds the point of transition from aerobic to anaerobic metabolism is accompanied by a quadratic decline in affective valence. This marker may be useful in aiding exercisers to recognize the transition to anaerobic metabolism and, thus, more effectively self-monitor and self-regulate the intensity of their efforts.

Adult↗

PubMed2002

The affective beneficence of vigorous exercise revisited.

OBJECTIVES: High exercise intensity may be associated with reduced adherence to exercise programmes, possibly because it is perceived as aversive. However, several authors have suggested that an intensity as high as 60% or 70% of maximal aerobic capacity (VO(2max)) is necessary for exercise to elicit positive affective changes. To elucidate this discrepancy, the affective responses to increasing levels of exercise intensity were examined. DESIGN: In total, 30 volunteers rated their affect every minute as they ran on a treadmill while the speed and grade were progressively increased. METHOD: The methodology was unique in three respects: (1) affect was assessed in terms of the dimensions of the circumplex model instead of distinct affective states, (2) affect was assessed repeatedly before, during, and after exercise, not only before and after, and (3) exercise intensity was standardized across participants in terms of metabolically comparable phases (beginning, ventilatory threshold, VO(2max)) instead of percentages of maximal capacity. RESULTS: Pre-to-post-exercise comparisons indicated affective benefits in the form of increased energetic arousal and decreased tense arousal. During exercise, however, affective valence deteriorated beyond the ventilatory threshold and until VO(2max), a trend that reversed itself instantaneously during cool-down. CONCLUSIONS: Exercise intensity that requires a transition to anaerobic metabolism can have a transient but substantial negative impact on affect and this may, in turn, reduce adherence to exercise programmes.

Journal Article↗