Psychological Responses to Acute Exercise in Sedentary Black and White Individuals

Background: Racial differences in psychological determinants of exercise exist between non-Hispanic blacks (blacks) and non-Hi.spanic whites (whites). To date, no study has examined racial differences in the psychological responses during and after exercise. The objective of tbis study was to compare psychological outcomes of single exercise bouts in blacks and whites. Methods: On 3 separate occasions, sedentary black (n = 16) and white (n = 14) participants walked on a treadmill at 75%max tm for 75 minutes. Questionnaires assessing mocxi, state anxiety, and exercise task self-efficacy were administered before and after each exercise bout. In-task mood and rating of perceived exertion (RPE) were measured every 5 minutes during exercise. Results: Exercise self-efficacy and psychological distress significantly improved in both blacks and whites. However during exercise blacks reported more positive in-task mood and lower RPE compared with whites. Conclusions: These data suggest that racial differences exist in psychological responses during exercise. Further research should confirm these findings in a larger, free-living populatio

The effects of interrupting prolonged sitting with intermittent activity on appetite sensations and subsequent food intake in preadolescent children

<div><p>Background</p><p>Short-term and long-term exposure to prolonged sitting is associated with excess food intake and weight gain in children. Interrupting prolonged sitting with low-intensity activity has been shown to not alter hunger, satiety, or food consumption in children, however it is unclear whether interrupting sitting with high-intensity activity will alter appetite regulation in children.</p><p>Purpose</p><p>The purpose of this study was to examine the acute effects of interrupting prolonged sitting with intermittent activity performed at varying intensities on hunger, satiety, prospective food consumption (PFC), and food intake in preadolescent children.</p><p>Methods</p><p>Thirty-nine children (ages 7–11 years, 54% female, 33% overweight/obese) completed four experimental conditions in random order: 8 hours of sitting interrupted with 20, 2-minute low-, moderate-, or high-intensity activity breaks or 20, 2-minute sedentary screen time breaks. Exercise intensity corresponded with 25%, 50% and 75% of heart rate reserve, respectively. Hunger, satiety, and PFC were assessed using the Visual Analog Scale, at five time points (pre- and post-breakfast, pre- and post-lunch, and pre-dinner) during each experimental condition. Dietary compensation was assessed as total caloric intake during a post-condition dinner standardized to provide 70% of estimated daily energy requirements.</p><p>Results</p><p>There was a significant effect of time on hunger, satiety, and PFC throughout each condition day (p< 0.001). There were no differences across conditions for hunger (sedentary: 4.9±0.3 cm, low: 5.0±0.3 cm, moderate: 5.1±0.3 cm, high: 5.1±0.3 cm, p>0.05), satiety (sedentary: 4.7±0.3 cm, low: 4.4±0.3 cm, moderate: 4.6±0.3 cm, high: 4.2±0.3 cm, p>0.05), and PFC (sedentary: 4.9±0.3 cm, low: 4.7±0.3 cm, moderate: 4.9±0.3 cm, high: 5.0±0.3 cm, p>0.05). There were no significant differences in post-activity food intake across conditions (sedentary: 1071.9±53.6 kcals; low: 1092.6±43.4kcals; moderate: 996.2±54.6kcals; high: 1138.7±62.8kcals, p>0.05). However, there was a significant effect of condition on energy balance (sedentary: +61.4±65.9 kcals, low: +74.9±57.6 kcals, moderate: -58.3±62.8 kcals, high: -391.2±77.9 kcals; p<0.001). There were no significant effects of weight status on hunger, satiety, PFC, post-activity food intake, and mean energy balance across conditions (all p’s>0.05).</p><p>Conclusions</p><p>Interrupting prolonged sitting with physical activity of any intensity does not alter appetite sensations and subsequent food consumption in children. These data suggest that interventions targeting prolonged sitting with high-intensity intermittent activity may be an effective strategy to increase physical activity energy expenditure without increasing food intake, allowing for a short-term energy deficit in both healthy weight and overweight/obese children. Future studies should examine the long-term effects of interrupting prolonged sitting with activity on food consumption and weight status in preadolescent children.</p></div

Mean energy balance across conditions.

<p>Asterisk denotes a significant difference between conditions. Normal weight participant data on the left, overweight/obese participant data on the right.</p

Subjective feelings of PFC throughout each experimental condition day.

<p>(A) PFC appetite sensations throughout condition day. Asterisk denotes significant effect of time between pre- and post-meal times. (B) AUCs of PFC for each experimental condition. Normal weight participant data on the left, overweight/obese participant data on the right.</p

Timeline of condition day.

<p>Stars indicate when Visual Analog Scale was administered. Thick black bars indicate times when activity breaks were completed.</p

Subjective feelings of satiety throughout each experimental condition day.

<p>(A) Satiety appetite sensations throughout condition day. Asterisk denotes significant effect of time between pre- and post-meal times. (B) AUCs of satiety for each experimental condition. Normal weight participant data on the left, overweight/obese participant data on the right.</p

Subjective feelings of hunger throughout each experimental condition day.

<p>(A) Hunger appetite sensations throughout condition day. Asterisk denotes significant effect of time between pre- and post-meal times. (B) AUCs of hunger for each experimental condition. Normal weight participant data on the left, overweight/obese participant data on the right. Asterisk denotes significant effect of condition, # denotes trend at p = 0.09.</p