Kym Janese Guelfi

The aim of this study was to investigate the effect of sprint interval training (SIT) and psychological need-support in exercise on postexercise appetite and energy intake. Forty physically inactive men and women (body mass index, 24.6 ± 4.8 kg·m⁻²; peak oxygen consumption, 26.6 ± 4.9 mL·kg⁻¹·min⁻¹) were randomised to either a need-support or no-support condition, with each participant completing 2 experimental trials involving 30 min of moderate-intensity continuous training (MICT; 60% peak oxygen consumption) and SIT (alternating 15 s at 170% peak oxygen consumption and 60 s at 32% peak oxygen consumption) matched for total work. Perceptions of appetite and appetite-related blood variables were assessed, together with ad libitum energy intake for 3 h following exercise using a laboratory test meal and available snacks. Greater enjoyment, perceived exertion, heart rate, and blood lactate were observed in SIT compared with MICT (all p ≤ 0.006). Ratings of perceived appetite were similar across conditions and trials (p > 0.05); however, active ghrelin was lower following SIT compared with MICT (p < 0.001), and there was a significant condition-by-type interaction for energy intake (p = 0.033), with participants in the support group consuming less energy from foods following SIT (1895 ± 1040 kJ) than MICT (2475 ± 1192 kJ). Findings from this work highlight the need to reconsider traditional exercise guidelines where dietary intake is a concern. Novelty Enjoyment was greater during SIT compared with MICT. Enjoyment and choice were higher among participants provided with psychological need-support. In a need-supportive environment, SIT reduced subsequent energy intake compared with MICT.

Despite the acknowledgment of exercise as a cornerstone in the management of type 2 diabetes (T2D), the importance of exercise timing has only recently been considered. Purpose: This study sought to determine the effect of diurnal exercise timing on glycemic control in individuals enrolled in a 12-wk supervised multimodal exercise training program. A secondary aim was to determine the effect of diurnal exercise timing on the circadian rhythm of wrist skin temperature. Methods: Forty sedentary, overweight adults (mean ± SD, age = 51 ± 13 yr; body mass index = 30.9 ± 4.2 kg·m⁻²; women, n = 23) with and without (n = 20) T2D diagnosis were randomly allocated to either a morning (amEX) or an evening (pmEX) exercise training group. The supervised 12-wk (3 d·wk⁻¹) program, comprised 30 min of moderate-intensity walking and 4 resistance-based exercises (3 sets, 12–18 repetitions each). Glycemic outcomes (glycated hemoglobin, fasting glucose, postprandial glucose) and wrist skin temperature were assessed at baseline and postintervention. Results: Exercise training improved (main effect of time, all P < 0.01) all glycemic outcomes; however, this was independent of allocation to either the amEX (Hedge’s g, 0.23–0.90) or the pmEX (Hedge’s g, 0.16–0.90) group. Accordingly, the adopted exercise training program did not alter the circadian rhythm of skin temperature. When only T2D individuals were compared, amEX demonstrated greater effects (all Hedge’s g) on glycated hemoglobin (amEX, 0.57; pmEX, 0.32), fasting glucose (amEX, 0.91; pmEX, 0.53), and postprandial glucose (amEX, 1.12; pmEX, 0.71) but was not statistically different. Conclusions: Twelve weeks of multimodal exercise training improved glycemic control and postprandial glycemic responses in overweight non-T2D and T2D individuals. However, no distinct glycemic benefits or alterations in circadian rhythm were associated with morning versus evening exercise, when performed three times per week in this cohort.

Background: Stress is often associated with the intake of energy‐dense palatable foods. This trial examined the feasibility and preliminary efficacy of an 8‐week worksite‐based relaxation intervention to address psychological stress and unhealthy food intake. Methods: Thirty‐six men and women were exposed to an acute stressor, while physiological and psychological responses were assessed, prior to being offered a test meal. Participants were then randomised to a relaxation intervention ( RELAX ; face‐to‐face classes and daily home practice of progressive muscle relaxation and mindfulness meditation), or a wait‐list control ( CON ). All measures were repeated after the intervention. Results: Intervention compliance was high (80% ± 19% face‐to‐face; 79% ± 18% home practice), and each session acutely reduced perceived stress ( p < .001) and increased relaxation ( p  < .001). After 8 weeks, trait mindfulness was increased ( p = .025), along with reduced tension ( p = .013) and increased relaxation ( p < .05) post‐acute stressor in the intervention group. There was no effect of the intervention on palatable eating, cravings, or energy intake at a laboratory test meal, with small associated effect sizes ( d  =   0.01–0.3). Conclusions: The program studied here is feasible and sessions transiently reduce perceived stress and improve mindfulness; however, the program may not influence the physiological response to an acute stressor or appetite and eating variables.

Background: Given previous research suggests an association between stress and the intake of energy‐dense foods, this study investigated whether poststressor relaxation practice can attenuate stress‐induced eating.Methods: Twenty‐five men and women were exposed to four conditions on separate days: an acute laboratory stressor (S), acute stressor followed by 20 min of relaxation (SR) in the form of Abbreviated Progressive Muscle Relaxation (APMR), relaxation alone (R), and a control condition (C). Physiological and psychological responses to stress and relaxation were assessed, in addition to the subsequent energy intake of high‐energy snacks.Results: Salivary cortisol, blood pressure, heart rate, and perceived stress were transiently elevated postlaboratory stressor (S and SR compared with R and C; p < .05). Meanwhile, perceived relaxation was acutely enhanced after APMR alone (R) compared with S, SR, and C (p < .05) and in SR (immediately after the APMR) compared with S (p < .05). No difference in mean energy intake was observed between conditions (p > .05). Likewise, no differences in perceived appetite or the levels of ghrelin, leptin, and insulin were found between conditions (p > .05).Conclusions: Much variation exists in stress‐induced dietary responses, and APMR either postacute stressor or in isolation does not appear to consistently alter the intake of commonly eaten snacks.

Objectives: To identify if maternal educational attainment is a prognostic factor for gestational weight gain (GWG), and to determine the differential effects of lifestyle interventions (diet based, physical activity based or mixed approach) on GWG, stratified by educational attainment. Design: Individual participant data meta-analysis using the previously established International Weight Management in Pregnancy (i-WIP) Collaborative Group database (https://iwipgroup.wixsite.com/collaboration). Preferred Reporting Items for Systematic reviews and Meta-Analysis of Individual Participant Data Statement guidelines were followed. Data sources: Major electronic databases, from inception to February 2017. Eligibility criteria: Randomised controlled trials on diet and physical activity-based interventions in pregnancy. Maternal educational attainment was required for inclusion and was categorised as higher education (≥tertiary) or lower education (≤secondary). Risk of bias: Cochrane risk of bias tool was used. Data synthesis: Principle measures of effect were OR and regression coefficient. Results: Of the 36 randomised controlled trials in the i-WIP database, 21 trials and 5183 pregnant women were included. Women with lower educational attainment had an increased risk of excessive (OR 1.182; 95% CI 1.008 to 1.385, p =0.039) and inadequate weight gain (OR 1.284; 95% CI 1.045 to 1.577, p =0.017). Among women with lower education, diet basedinterventions reduced risk of excessive weight gain (OR 0.515; 95% CI 0.339 to 0.785, p = 0.002) and inadequate weight gain (OR 0.504; 95% CI 0.288 to 0.884, p=0.017), and reduced kg/week gain (B −0.055; 95% CI −0.098 to −0.012, p=0.012). Mixed interventions reduced risk of excessive weight gain for women with lower education (OR 0.735; 95% CI 0.561 to 0.963, p=0.026). Among women with high education, diet based interventions reduced risk of excessive weight gain (OR 0.609; 95% CI 0.437 to 0.849, p=0.003), and mixed interventions reduced kg/week gain (B −0.053; 95% CI −0.069 to −0.037,p<0.001). Physical activity based interventions did not impact GWG when stratified by education. Conclusions: Pregnant women with lower education are at an increased risk of excessive and inadequate GWG. Diet based interventions seem the most appropriate choice for these women, and additional support through mixed interventions may also be beneficial.