Behavioural compensatory and metabolic changes in response to exercise in overweight and obese women

This thesis describes the behavioural compensatory responses and metabolic changes in response to a single exercise session and training programmes in overweight and obese women and consists of a literature review (Chapter 1), a general methods chapter (Chapter 2), three experimental chapters (Chapter 3- Chapter 5) and a general discussion and conclusions chapter (Chapter 6). Experimental chapter 3 presents a study which aimed to investigate the impact of a single moderate-intensity cycling exercise session with energy expenditure of approximately 2 MJ on appetite measures, energy intake and metabolic variables in response to four ad libitum meals in overweight and obese females. Twelve sedentary, overweight and obese women underwent one exercise and one control trial each over two consecutive days. Appetite and metabolic variables such as glucose, insulin and triglycerides were measured frequently and four buffet meals were served throughout each trial. The findings suggest that a single exercise session performed by overweight and obese women does not elicit compensatory responses in appetite and energy intake and reduces triglyceride concentration by 17% in response to an ad libitum breakfast consumed 14 hours after exercise. Chapter 4 aimed to examine the extent to which changes in physical activity outside of the exercise intervention and energy intake contribute to individual differences in body fat loss induced by exercise training programmes. To determine this, thirty-four overweight and obese sedentary women participated in a structured and supervised 8-week exercise programme consisting of 150 minutes of cycling exercise per week. Body composition, total energy expenditure and components such as exercise, activity, sedentary and sleeping energy expenditure as well as energy intake from 7-day weighed intake were determined before and during the last week of the exercise intervention. The findings indicate that overweight and obese women who during exercise intervention achieve lower than predicted fat loss are compensating by being less active outside exercise sessions. The aim of Chapter 5 was to investigate how physical, fitness and metabolic characteristics of overweight and obese women are influenced by two 8-week supervised aerobic exercise programmes with exercise sessions conducted twice per week for the duration of 75 minutes and with exercise sessions conducted 5 times per week for the duration of 30 minutes. Thirty-four women were randomised into either long and less frequent or short and more frequent cycling exercise groups. Body composition, fitness and metabolic variables were measured prior and after the intervention. The findings indicate that frequency and duration of exercise sessions does not alter the effects of an exercise programme on health related outcomes which were evident in the absence of weight loss, when the total volume of exercise undertaken is the same. Based on obtained data the following conclusions have been drawn: Overweight and obese women do not compensate in terms of appetite and energy intake for the energy expended in a single exercise session, when this is in line with recommended expenditure for individual exercise sessions aimed at body weight and body fat reduction. Compensatory responses in terms of changes in energy intake are also not evident in overweight and obese women participating in an 8-week exercise training programme. However, predicted body fat loss can be expected to match the amount of fat actually lost only in those who do not decrease physical activity outside exercise sessions. A single exercise session with energy expenditure similar to that recommended for individual exercise sessions aiming at body mass and body fat reduction, reduced triglyceride concentration by 17% in response to an ad libitum breakfast consumed 14 hours after exercise. Changes in fitness, insulin resistance, diastolic blood pressure and waist circumference in sedentary overweight and obese women induced by an 8-week exercise programme incorporating 150 minutes of exercise per week are independent of frequency and duration of exercise sessions with 2 x 75 minute exercise sessions per week and 5 x 30 minute exercise sessions per week eliciting similar changes

Effect of pomegranate juice consumption on biochemical parameters and complete blood count

Pomegranate has been used therapeutically for centuries. The aim of the present study was to examine the effects of pomegranate juice (PJ) supplementation on complete blood count (CBC), glucose, blood lipids and C‑reactive protein (CRP) in healthy subjects. A total of 5 males and 5 females (aged 31.8±6.6 years, weighing 66.2±12.9 kg) were randomly assigned into one of two groups and either consumed 500 ml PJ/day or no PJ for 14 days. Blood samples were obtained from participants prior to and following the experimental period. PJ consumption resulted in a significant increase in red blood cell count (P<0.05), hemoglobin levels (P<0.001) and hematocrit levels (P<0.05). Other CBC parameters, glucose, cholesterol, triglycerides, high‑density lipoprotein, low‑density lipoprotein and CRP levels did not significantly change following PJ consumption. These results indicate that PJ intake for a short period of time may result in increased erythropoiesis or decreased degradation without any significant alterations in factors associated with metabolic health and inflammation in healthy individuals

Validity of predictive equations to estimate RMR in females with varying BMI

Estimation of RMR using prediction equations is the basis for calculating energy requirements. In the present study, RMR was predicted by Harris–Benedict, Schofield, Henry, Mifflin–St Jeor and Owen equations and measured by indirect calorimetry in 125 healthy adult women of varying BMI (17–44 kg/m2). Agreement between methods was assessed by Bland–Altman analyses and each equation was assessed for accuracy by calculating the percentage of individuals predicted within ± 10 % of measured RMR. Slopes and intercepts of bias as a function of average RMR (mean of predicted and measured RMR) were calculated by regression analyses. Predictors of equation bias were investigated using univariate and multivariate linear regression. At group level, bias (the difference between predicted and measured RMR) was not different from zero only for Mifflin–St Jeor (0 (sd 153) kcal/d (0 (sd 640) kJ/d)) and Henry (8 (sd 163) kcal/d (33 (sd 682) kJ/d)) equations. Mifflin–St Jeor and Henry equations were most accurate at the individual level and predicted RMR within 10 % of measured RMR in 71 and 66 % of participants, respectively. For all equations, limits of agreement were wide, slopes of bias were negative, and intercepts of bias were positive and significantly (P &lt; 0⋅05) different from zero. Increasing age, height and BMI were associated with underestimation of RMR, but collectively these variables explained only 15 % of the variance in estimation bias. Overall accuracy of equations for prediction of RMR is low at the individual level, particularly in women with low and high RMR. The Mifflin–St Jeor equation was the most accurate for this dataset, but prediction errors were still observed in about one-third of participants

Validity of predictive equations to estimate RMR in females with varying BMI

Estimation of RMR using prediction equations is the basis for calculating energy requirements. In the present study, RMR was predicted by Harris–Benedict, Schofield, Henry, Mifflin–St Jeor and Owen equations and measured by indirect calorimetry in 125 healthy adult women of varying BMI (17–44 kg/m2). Agreement between methods was assessed by Bland–Altman analyses and each equation was assessed for accuracy by calculating the percentage of individuals predicted within ± 10 % of measured RMR. Slopes and intercepts of bias as a function of average RMR (mean of predicted and measured RMR) were calculated by regression analyses. Predictors of equation bias were investigated using univariate and multivariate linear regression. At group level, bias (the difference between predicted and measured RMR) was not different from zero only for Mifflin–St Jeor (0 (sd 153) kcal/d (0 (sd 640) kJ/d)) and Henry (8 (sd 163) kcal/d (33 (sd 682) kJ/d)) equations. Mifflin–St Jeor and Henry equations were most accurate at the individual level and predicted RMR within 10 % of measured RMR in 71 and 66 % of participants, respectively. For all equations, limits of agreement were wide, slopes of bias were negative, and intercepts of bias were positive and significantly (P &lt; 0⋅05) different from zero. Increasing age, height and BMI were associated with underestimation of RMR, but collectively these variables explained only 15 % of the variance in estimation bias. Overall accuracy of equations for prediction of RMR is low at the individual level, particularly in women with low and high RMR. The Mifflin–St Jeor equation was the most accurate for this dataset, but prediction errors were still observed in about one-third of participants

Enhanced erythrocyte antioxidant status following an 8-week aerobic exercise training program in heavy drinkers

Alcohol-induced oxidative stress is involved in the development and progression of various pathological conditions and diseases whereas exercise training has been shown to improve redox status, thus attenuating oxidative stress-associated disease processes. PURPOSE: to evaluate the effect of an exercise training program on blood redox status in heavy drinkers. METHODS: Eleven sedentary, heavy drinking men participated in an intervention where they completed an 8-week supervised aerobic training program of moderate intensity. Blood samples were collected before, during (week 4) and after intervention and analyzed for total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), protein carbonyls (PC), uric acid (UA), bilirubin, reduced glutathione (GSH) and catalase activity. RESULTS: Catalase activity increased (p<0.05) after 8 weeks (340.7+13.3 U mg/Hb) of intervention compared to week 4 (299.5+18.7 U mg/Hb). GSH increased (p<0.05) after 8 weeks of intervention (1.22+0.16 μmol/g Hb) compared to the control condition (1.11 + 0.17 μmol/g Hb) and to week 4 (1.11 + 0.15 μmol/g Hb ). TAC, UA, bilirubin, TBARS and PC did not significantly change at any time point. CONCLUSION: An 8-week aerobic training program enhanced erythrocyte antioxidant status in heavy drinkers, indicating that aerobic training may attenuate pathological processes caused by alcohol-induced oxidative stress.Published versio

Exercise training reduces alcohol consumption but does not affect HPA-axis activity in heavy drinkers

It has been suggested that physical exercise could have potential beneficial effects in substance abusers, which are based on both physiological and psychological theories. Although a few studies have examined the effect of exercise on alcohol intake and fitness in individuals with alcohol use disorders (AUDs), there is a gap in the literature concerning the physiological and biochemical mechanisms that could be affected by physical exercise in this population

Effect of exercise programmes with aerobic exercise sessions of similar intensity but different frequency and duration on health related measures in overweight women

&lt;b&gt;Background:&lt;/b&gt; This study investigated health related effects of exercise programmes with exercise sessions of similar intensity but different frequency and duration. &lt;b&gt;Methods:&lt;/b&gt; Thirty four overweight women were randomised into either long bout (LB) or short bout (SB) exercise groups. Participants performed an 8-week supervised programme, with the LB group exercising for 75 minutes twice per week, and the SB group for 30 minutes on five days of the week. &lt;b&gt;Results:&lt;/b&gt; The LB group completed 16 sessions at a HR of 127 ± 1 beat·min-1 and the SB group completed 40 sessions at a HR of 126 ± 1 beat·min-1. Weekly energy expenditure of exercise was not different between groups (LB group, 5.64 ± 0.34 MJ; SB group, 5.83 ± 0.23 MJ). Training significantly (p&#60;0.05) increased measures of cardiorespiratory fitness, decreased waist circumference, insulin resistance, and diastolic blood pressure. The group x time interaction was not significant for any of these factors, indicating that responses to exercise training did not differ between the SB and LB groups. &lt;b&gt;Conclusions:&lt;/b&gt; Health related outcomes of exercise programmes with similar energy expenditure are independent of frequency and duration of exercise sessions. This provides individuals with a degree of flexibility in exercise programme planning

Appetite Control in Response to a Single Exercise Session in Overweight/Obese Women

No abstract available

An initial investigation of smokers’ urges to smoke and their exercise intensity preference: A mixed-methods approach

 The purpose of this study was to examine whether smokers preferred a “self-selected” form of physical activity (PA) in which they were allowed to determine themselves the intensity of PA or preferred a “set” form of PA in which the instructor chose the exercise intensity for them. In addition, we examined effects of ‘set” and “self-selected” intensity exercise, on urges to smoke. Participants were 20 (mean age = 27.10 ± 7.37) adults, non-physically active, heavy smokers. Four of them were also interviewed. Results demonstrated that smokers exhibited an enhanced preference for “self-selected” forms of PA as opposed to “set” forms of PA. Smoking urge was significantly lower immediately after exercise in both conditions, returned to baseline levels at 30 min post-exercise, and increased further at 60 min post-exercise. Qualitative data supported the quantitative findings and gave insight to dimensions that needs to be taken under account when we design exercise programs for smokers. The implication of the overall findings is that smoking cessation and motivation for PA participation can be increased by allowing smokers to select intensity of PA programs.peerReviewe

The Relationship Between Motor Proficiency and Pedometer-Determined Physical Activity in Young Children

The aim of this study was to examine the relationship between motor proficiency and pedometer-determined physical activity in 5-6 year-old children. Participants (n = 232) were randomly recruited and assessed from 30 kindergartens in Northern Greece. Two trained researchers administered the measurements for the assessment of children’s motor proficiency by using the BOTMP-SF. Physical activity was assessed by OMRON pedometers. Significant relationships between BOTMP-SF standard score and steps (S), aerobic walking time (AWT) and aerobic steps (AS), &lt; .05) were found. When motor proficiency was divided into quartiles to assess the distribution of the relationship between motor proficiency and pedometer-derived variables, significant associations were found for AWT, S and AS (p &lt; .001). Young children with high levels of motor proficiency were more active in contrast to their peers with lower motor proficiency. The findings add to the growing body of literature that considers motor skills/ abilities as important elements of physical activity participation. (Abbreviations: S-steps per day; AS-aerobic steps per day; AWT-aerobic walking time (minutes.day(-1)); BOTMP-SF-Bruininks-Oseretsky Test of Motor Proficiency-Short Form (standard score)