Examining the effectiveness of the theory of planned behaviour in explaining exercise intention and behaviour during pregnancy: a meta-analysis

Background: Several studies have supported the efficacy and predictive utility of the Theory of Planned Behaviour (TPB; Ajzen 1991) in explaining a variety of behaviours including physical activity. However, the relative contribution of the theory’s components in describing intention and behaviour may differ depending on the context, time and population being studied. Such evidence is necessary to inform exercise advice and interventions aimed at pregnant women. Purpose: The purpose of this study was therefore to review the existing literature surrounding the application of the TPB in explaining exercise intentions and behaviour during pregnancy and to evaluate the magnitude of relationships between TPB constructs within this context. Method: Multiple search strategies yielded 99 potentially relevant studies of which 47 were assessed against the inclusion criteria. Finally, 7 studies, involving 777 pregnant women, were included in the analysis. Relationships identified among TPB constructs were subjected to a random-effects meta-analytic review using the Comprehensive Meta-Analysis (version 3.0) computer software package. Results: Results confirmed the existence of a medium to strong relationship between intention and behaviour (r = 0.44, P < 0.05, R2 = 19.36) and also supported the existence of a direct relationship between behaviour and perceived behavioural control (PBC; r = 0.45, P < 0.05, R2 = 20.25). Pregnant women’s attitude (r = 0.48, P < 0.05, R2 = 23.04) had the strongest association with their intention to be physically active. However, both PBC (r = 0.47, P < 0.05, R2 = 22.09) and subjective norm (r = 0.42, P < 0.05, R2 = 17.64) revealed similar relationships with intention. Conclusion: The study supports the TPB as a relevant conceptual framework for the investigation of exercise intentions and behaviours during pregnancy. PBC carried slightly more weight in explaining behaviour than did intention thereby suggesting that exercise during pregnancy is not a behaviour that is under women’s complete volitional control. Intention to exercise was influenced primarily by expectant mothers’ beliefs about the positive and negative consequences of doing so. Contrary to previous meta-analytic reports in the exercise domain, this study supported the relevance of subjective norm as a construct to investigate exercise intentions and behaviour in a pregnant population. The perceived social pressure to conform to other people’s opinion about physical activity during pregnancy may well be an important consideration for pregnant women. These findings present both researchers and practitioners with an opportunity for intervention and further research

Examining the effectiveness of the Theory of Planned Behaviour in predicting exercise intention and behaviour during pregnancy: Preliminary findings from a random effects meta-analysis

Several studies have supported the efficacy and predictive utility of the Theory of Planned Behaviour (TPB; Ajzen, 1991) in explaining a variety of behaviours including physical activity. However, the relative contribution of the theory’s components in describing intention and behaviour may differ depending on the context, time and population being studied. Such evidence is necessary to inform exercise advice and interventions aimed at pregnant women. The purpose of this study was therefore to review the existing literature surrounding the application of the TPB in explaining exercise intentions and behaviour during pregnancy and to evaluate the magnitude of relationships between TPB constructs within this context. Multiple search strategies yielded 99 potentially relevant studies of which 47 were assessed against the inclusion criteria. Finally, 7 studies, involving 777 pregnant women, were included in the analysis. Relationships identified among TPB constructs were subjected to a random-effects meta-analytic review using the Comprehensive Meta-Analysis (version 3.0) computer software package. Results confirmed the existence of a medium to strong relationship between intention and behaviour (r = .44, P < .05, R2 = 19.36) and also supported the existence of a direct relationship between behaviour and perceived behavioural control (PBC; r = .45, P < .05, R2 = 20.25). Pregnant women’s attitude (r = .48, P < .05, R2 = 23.04) had the strongest association with their intention to be physically active. However, both PBC (r = .47, P < .05, R2 = 22.09) and subjective norm (r = .42, P < .05, R2 = 17.64) revealed similar relationships with intention. The study supports the TPB as a relevant conceptual framework for the investigation of exercise intentions and behaviours during pregnancy. PBC carried slightly more weight in explaining behaviour than did intention thereby suggesting that exercise during pregnancy is not a behaviour that is under women’s complete volitional control. Intention to exercise was influenced primarily by expectant mothers’ beliefs about the positive and negative consequences of doing so. Contrary to previous meta-analytic reports in the exercise domain, this study supported the relevance of subjective norm as a construct to investigate exercise intentions and behaviour in a pregnant population. The perceived social pressure to conform to other people’s opinion about physical activity during pregnancy may well be an important consideration for pregnant women. These findings present both researchers and practitioners with an opportunity for intervention and further research

Paroxysmal eye–head movements in Glut1 deficiency syndrome

Objective:To describe a characteristic paroxysmal eye–head movement disorder that occurs in infants with Glut1 deficiency syndrome (Glut1 DS).Methods:We retrospectively reviewed the medical charts of 101 patients with Glut1 DS to obtain clinical data about episodic abnormal eye movements and analyzed video recordings of 18 eye movement episodes from 10 patients.Results:A documented history of paroxysmal abnormal eye movements was found in 32/101 patients (32%), and a detailed description was available in 18 patients, presented here. Episodes started before age 6 months in 15/18 patients (83%), and preceded the onset of seizures in 10/16 patients (63%) who experienced both types of episodes. Eye movement episodes resolved, with or without treatment, by 6 years of age in 7/8 patients with documented long-term course. Episodes were brief (usually &lt;5 minutes). Video analysis revealed that the eye movements were rapid, multidirectional, and often accompanied by a head movement in the same direction. Eye movements were separated by clear intervals of fixation, usually ranging from 200 to 800 ms. The movements were consistent with eye–head gaze saccades. These movements can be distinguished from opsoclonus by the presence of a clear intermovement fixation interval and the association of a same-direction head movement.Conclusions:Paroxysmal eye–head movements, for which we suggest the term aberrant gaze saccades, are an early symptom of Glut1 DS in infancy. Recognition of the episodes will facilitate prompt diagnosis of this treatable neurodevelopmental disorder.</jats:sec

Bump start needed: linking guidelines, policy and practice in promoting physical activity during and beyond pregnancy

First paragraph: There is compelling evidence that regular physical activity (PA) during pregnancy benefits both mother and baby.1 2 Notably, physical and psychological benefits are evident in the literature, such as marked reductions in the development of gestational diabetes and hypertensive disorders, alongside improvements in depressive symptoms and cardiorespiratory fitness.1 2 The evidence base has been reflected by recent policy initiatives, for example, in 2017 (relaunched in 2019), the UK‘s chief medical officers (CMOs) published PA guidelines for pregnant women, which made substantial strides in unifying and translating the evidence into recommendations.1 The CMO guidelines are aimed at supporting health professionals to provide consistent, evidence-based PA messages to women throughout pregnancy.1 Recently, the Chartered Institute for the Management of Sport and Physical Activity have updated their professional standards for working with antenatal and postnatal clients to align with these CMO guidelines.3 However, not all women have access to professionals with this level of expertise and training, potentially limiting the impact of the CMO guidelines

Embedding physical activity guidance during pregnancy and in postpartum care: ‘This Mum Moves’ enhances professional practice of midwives and health visitors

Introduction: The benefits of physical activity during pregnancy and after childbirth are well established, yet many health care professionals do not feel well equipped to provide physical activity guidance to these populations. As such, the objectives of this study were to explore the immediate and longer term effects of training on health care professionals’ ability to provide physical activity guidance to pregnant women and new mothers (mums). Methods: Midwives and health visitors from five locations in the United Kingdom were provided with training on the Chief Medical Officers' physical activity guidelines for pregnancy and after childbirth (n=393). Midwives and health visitors attended training to become This Mum Moves Ambassadors, then disseminated education to colleagues through a cascade training model. Changes in knowledge, confidence, and professional practice were assessed by survey before and immediately after training (n=247), and follow-up surveys were completed 3 (n=35) and 6 (n=34) months post training. Results: At all post training time points, health care professionals reported a significant increase in their confidence to communicate about physical activity (P < .001). The reported frequency of having conversations about physical activity increased significantly 3 and 6 months following training compared to baseline (pregnant women, P = .017; new mums, P = .005). There were changes in the types of advice and resources offered by health care professionals, and an overall increase in health care professionals’ own reported physical activity levels. Discussion: The This Mum Moves cascade approach to delivering training in physical activity guidelines improved reported knowledge, confidence and professional practice of midwives and health visitors, both immediately following and 3 and 6 months after training

Int J Environ Res Public Health

Few studies have explored temperature-mortality relationships in China, especially at the multi-large city level. This study was based on the data of seven typical, large Chinese cities to examine temperature-mortality relationships and optimum temperature of China. A generalized additive model (GAM) was applied to analyze the acute-effect of temperature on non-accidental mortality, and meta-analysis was used to merge data. Furthermore, the lagged effects of temperature up to 40 days on mortality and optimum temperature were analyzed using the distributed lag non-linear model (DLNM). We found that for all non-accidental mortality, high temperature could significantly increase the excess risk (ER) of death by 0.33% (95% confidence interval: 0.11%, 0.56%) with the temperature increase of 1 \uc2\ub0C. Similar but non-significant ER of death was observed when temperature decreased. The lagged effect of temperature showed that the relative risk of non-accidental mortality was lowest at 21 \uc2\ub0C. Our research suggests that high temperatures are more likely to cause an acute increase in mortality. There was a lagged effect of temperature on mortality, with an optimum temperature of 21 \uc2\ub0C. Our results could provide a theoretical basis for climate-related public health policy.26950139PMC480894

Sleep and wake affect glycogen content and turnover at perisynaptic astrocytic processes

Astrocytic glycogen represents the only form of glucose storage in the brain, and one of the outcomes of its breakdown is the production of lactate that can be used by neurons as an alternative energetic substrate. Since brain metabolism is higher in wake than in sleep, it was hypothesized that glycogen stores are depleted during wake and replenished during sleep. Furthermore, it was proposed that glycogen depletion leads to the progressive increase in adenosine levels during wake, providing a homeostatic signal that reflects the buildup of sleep pressure. However, previous studies that measured glycogen dynamics across the sleep/wake cycle obtained inconsistent results, and only measured glycogen in whole tissue. Since most energy in the brain is used to sustain synaptic activity, here we employed tridimensional electron microscopy to quantify glycogen content in the astrocytic processes surrounding the synapse. We studied axon-spine synapses in the frontal cortex of young mice after ~7 h of sleep, 7–8 h of spontaneous or forced wake, or 4.5 days of sleep restriction. Relative to sleep, all wake conditions increased the number of glycogen granules around the synapses to a similar extent. However, progressively longer periods of wake were associated with progressively smaller glycogen granules, suggesting increased turnover. Despite the increased number of granules, in all wake conditions the estimated amount of glucose within the granules was lower than in sleep, indicating that sleep may favor glucose storage. Finally, chronic sleep restriction moved glycogen granules closer to the synaptic cleft. Thus, both short and long wake lead to increased glycogen turnover around cortical synapses, whereas sleep promotes glycogen accumulation

Higher arc nucleus-to-cytoplasm ratio during sleep in the superficial layers of the mouse cortex

The activity-regulated cytoskeleton associated protein Arc is strongly and quickly upregulated by neuronal activity, synaptic potentiation and learning. Arc entry in the synapse is followed by the endocytosis of glutamatergic AMPA receptors (AMPARs), and its nuclear accumulation has been shown in vitro to result in a small decline in the transcription of the GluA1 subunit of AMPARs. Since these effects result in a decline in synaptic strength, we asked whether a change in Arc dynamics may temporally correlate with sleep-dependent GluA1 down-regulation. We measured the ratio of nuclear to cytoplasmic Arc expression (Arc Nuc/Cyto) in the cerebral cortex of EGFP-Arc transgenic mice that were awake most of the night and then perfused immediately before lights on (W mice), or were awake most of the night and then allowed to sleep (S mice) or sleep deprived (SD mice) for the first 2 h of the light phase. In primary motor cortex (M1), neurons with high levels of nuclear Arc (High Arc cells) were present in all mice, but in these cells Arc Nuc/Cyto was higher in S mice than in W mice and, importantly, ~15% higher in S mice than in SD mice collected at the same time of day, ruling out circadian effects. Greater Arc Nuc/Cyto with sleep was observed in the superficial layers of M1, but not in the deep layers. In High Arc cells, Arc Nuc/Cyto was also ~15%–30% higher in S mice than in W and SD mice in the superficial layers of primary somatosensory cortex (S1) and cingulate cortex area 1 (Cg1). In High Arc Cells of Cg1, Arc Nuc/Cyto and cytoplasmic levels of GluA1 immunoreactivities in the soma were also negatively correlated, independent of behavioral state. Thus, Arc moves to the nucleus during both sleep and wake, but its nuclear to cytoplasmic ratio increases with sleep in the superficial layers of several cortical areas. It remains to be determined whether the relative increase in nuclear Arc contributes significantly to the overall decline in the strength of excitatory synapses that occurs during sleep. Similarly, it remains to be determined whether the entry of Arc into specific synapses is gated by sleep

Compact smallest eigenvalue expressions in Wishart-Laguerre ensembles with or without fixed-trace

The degree of entanglement of random pure states in bipartite quantum systems can be estimated from the distribution of the extreme Schmidt eigenvalues. For a bipartition of size M\geq N, these are distributed according to a Wishart-Laguerre ensemble (WL) of random matrices of size N x M, with a fixed-trace constraint. We first compute the distribution and moments of the smallest eigenvalue in the fixed trace orthogonal WL ensemble for arbitrary M\geq N. Our method is based on a Laplace inversion of the recursive results for the corresponding orthogonal WL ensemble by Edelman. Explicit examples are given for fixed N and M, generalizing and simplifying earlier results. In the microscopic large-N limit with M-N fixed, the orthogonal and unitary WL distributions exhibit universality after a suitable rescaling and are therefore independent of the constraint. We prove that very recent results given in terms of hypergeometric functions of matrix argument are equivalent to more explicit expressions in terms of a Pfaffian or determinant of Bessel functions. While the latter were mostly known from the random matrix literature on the QCD Dirac operator spectrum, we also derive some new results in the orthogonal symmetry class.Comment: 25 pag., 4 fig - minor changes, typos fixed. To appear in JSTA

Sleep Deprivation by Exposure to Novel Objects Increases Synapse Density and Axon-Spine Interface in the Hippocampal CA1 Region of Adolescent Mice

Sleep has been hypothesized to rebalance overall synaptic strength after ongoing learning during waking leads to net synaptic potentiation. If so, because synaptic strength and size are correlated, synapses on average should be larger after wake and smaller after sleep. This prediction was recently confirmed in mouse cerebral cortex using serial block-face electron microscopy (SBEM). However, whether these findings extend to other brain regions is unknown. Moreover, sleep deprivation by gentle handling was reported to produce hippocampal spine loss, raising the question of whether synapse size and number are differentially affected by sleep and waking. Here we applied SBEM to measure axon-spine interface (ASI), the contact area between pre-synapse and post-synapse, and synapse density in CA1 stratum radiatum. Adolescent YFP-H mice were studied after 6-8 h of sleep (S = 6), spontaneous wake at night (W = 4) or wake enforced during the day by novelty exposure (EW = 4; males/females balanced). In each animal ≥425 ASIs were measured and synaptic vesicles were counted in ~100 synapses/mouse. Reconstructed dendrites included many small, nonperforated synapses and fewer large, perforated synapses. Relative to S, ASI sizes in perforated synapses shifted toward higher values after W and more so after EW. ASI sizes in nonperforated synapses grew after EW relative to S and W, and so did their density. ASI size correlated with presynaptic vesicle number but the proportion of readily available vesicles decreased after EW, suggesting presynaptic fatigue. Thus, CA1 synapses undergo changes consistent with sleep-dependent synaptic renormalization and their number increases after extended wake.SIGNIFICANCE STATEMENT Sleep benefits learning, memory consolidation, and the integration of new with old memories, but the underlying mechanisms remain highly debated. One hypothesis suggests that sleep's cognitive benefits stem from its ability to renormalize total synaptic strength, after ongoing learning during wake leads to net synaptic potentiation. Supporting evidence for this hypothesis mainly comes from the cerebral cortex, including the observation that cortical synapses are larger after wake and smaller after sleep. Using serial electron microscopy, we find here that sleep/wake synaptic changes consistent with sleep-dependent synaptic renormalization also occur in the CA1 region. Thus, the role of sleep in maintaining synaptic homeostasis may extend to the hippocampus, a key area for learning and synaptic plasticity