Far from the walking pace. Ecological and evolutionary consequences of the suboptimal locomotion speeds in non-adult humans.

INTRODUCTION: Locomotion activities are part of most human daily tasks and are the basis for subsistence activities, particularly for hunter-gatherers. Therefore, differences in speed walking-related variables may have an effect, not only on the mobility of the group, but also on its composition. Some anthropometric parameters related to body length could affect walking speed-related variables and contribute to different human behaviors. However, there is currently little information on the influence of these parameters in nonadult individuals. METHODS: Overall, 11 females and 17 male child/adolescents, 8-17 years of age, volunteered to participate in this cross-sectional study. Five different pace walking tests were performed on a treadmill to calculate the optimal locomotion speed (OLS) and U-shaped relationship between the walking energy expenditure and speed (χ2 cost of transport [CoT]) (i.e., energetic walking flexibility). RESULTS: The mean OLS was 3.05 ± 0.13 miles per hour (mph), with no differences between sexes. Similarly, there were no sex differences in walking flexibility according to the χ2 CoT. Body height (p < .0001) and femur length (p < .001) were positively correlated with χ2 CoT; however, female child/adolescents mitigated the effect of height and femur length when walking at suboptimal speeds. CONCLUSION: Consistent with prior observations in adults, our findings suggest that anthropometric parameters related to body stature are associated with reduced suboptimal walking flexibility in children and adolescents. Taken together, these results suggest that children and adolescents can adapt their pace to the one of taller individuals without a highly energetic penalty, but this flexibility decreases with increasing body size.

It's about time to exercise: development of the Exercise Participation Explained in Relation to Time (EXPERT) model.

A perceived 'lack of time' is consistently the most commonly reported barrier to exercise. However, the term fails to capture the multifaceted nature of time-related factors. Recognising the need for a more comprehensive analysis of 'lack of time' as a barrier to exercise, the aim of this study was to develop the exercise participation explained in relation to time (EXPERT) model. The model was developed through a sequential process including (1) an umbrella literature review of time as a barrier, determinant, and correlate of physical activity; (2) a targeted review of existing temporal models; (3) drafting the model and refining it via discussions between eight authors; (4) a three-round Delphi process with eight panel members; and (5) consultations with seven experts and potential end-users. The final EXPERT model includes 31 factors within four categories: (1) temporal needs and preferences for exercise (ie, when and how long does an individual need/want to exercise), (2) temporal autonomy for exercise (ie, autonomy in scheduling free time for exercise), (3) temporal conditions for exercise (ie, available time for exercise) and (4) temporal dimensions of exercise (ie, use of time for exercise). Definitions, examples and possible survey questions are presented for each factor. The EXPERT model provides a comprehensive framework for understanding the multi-dimensional nature of 'time' as it relates to exercise participation. It moves beyond the simplistic notion of 'lack of time' and delves into the complexity of time allocation in the context of exercise. Empirical and cross-cultural validations of the model are warranted.

Internal medicine trainee perspectives on back-up call systems and relationships to burnout.

INTRODUCTION: As burnout within medicine escalates, residency programmes should strive to understand how training structures may contribute. Back-up call systems that address gaps in overnight resident call coverage are one possible contributing structure. However, the intersection between back-up call policies and burnout remains unclear. The authors explored residents' decision-making process when deciding whether or not to activate a back-up resident for call coverage, perspectives surrounding the legitimacy of call activations and the impact of back-up call systems on education and experienced burnout. METHODS: Internal medicine residents at the University of Toronto were recruited through email. Eighteen semi-structured one-on-one interviews were conducted with residents from September 2019 to February 2020. Interviews explored participants' experiences and perceptions with back-up call and call activations. A constructivist grounded theory approach was used to develop a conceptual understanding of the back-up system as it relates to residents' decisions underlying activations, downstream impacts and relationships to burnout. RESULTS: Residents described a complex thought process when deciding whether to activate back-up. Decisions were coloured by inner conflicts including sense of collegiality, need to maintain an image and time of year balanced against self-reported burnout. Residents described how back-up calls can lead to burnout, usually in the form of exhaustion, lowering their threshold to trigger future back-up activations. Impacts included anxiety of not knowing whether an activation would occur, decreased educational productivity and the 'domino effect' of increased workload for colleagues. DISCUSSION: Residents weigh inner tensions when deciding to activate back-up. Their collective experience suggests that burnout is both a trigger and consequence of back-up calls, creating a cyclical relationship. Escalating rates of call activations may signal that burnout amongst residents is high, warranting educational leads to assess for resident wellness and to critically evaluate the structure of such systems with respect to unintended consequences.

Dietary sugar intake and risk of Alzheimer's disease in older women.

BACKGROUND: Despite some reports of cardiometabolic disorders associated with the risk of Alzheimer's disease (AD), limited studies have been conducted to examine the association between excessive sugar intake (a risk factor for cardiometabolic disorders) and AD risk. AIM: The purpose of our study was to evaluate if excessive sugar intake has a significant long-term effect on the risk of AD. METHODS: A population sample of 37,689 participants, who enrolled in the United States (US) Women's Health Initiative - Dietary Modification Trial (WHI-DM) in 1993-2005 and its extended observational follow-up study through 1 March 2019, were analyzed. Dietary sugar intake was measured using food frequency questionnaires. AD was classified by reports using a standard questionnaire. A dietary pattern that explained the maxima variations in sugar intake was constructed using reduced rank regression (RRR) technique. Associations of RRR dietary pattern scores and sugar intake (g/day) by quartiles (Q1 through Q4) with AD risk were examined using Cox proportional hazards regression analysis with adjusting for key covariates. RESULTS: During a mean follow-up of 18.7 years, 4586 participants reported having incident AD. The total incidence rate (95% confidence interval [CI]) of AD was 6.5 (6.3-6.7) per 1000 person-years (PYs). The incidence rates (95% CI) of AD by total sugar intake were 6.2 (5.8-6.6), 6.4 (6.0-6.8), 6.6 (6.3-7.0), and 6.9 (6.5-7.3) per 1000 PYs among those in quartiles (Q) 1 to Q4 (toward higher sugar consumption) of total sugar intake, respectively (test for trend of AD incident rates, p < 0.001). Individuals in Q4 of total sugar intake had a 1.19 higher risk of incident AD than those in Q1 (hazard ratio [HR] = 1.19, 95% CI: 1.05-1.34, p = 0.01). An estimated increase of 10 g/day in total sugar intake (about 2.4 teaspoons) was associated with an increased AD risk by 1.3-1.4%. Of six subtypes of sugar intake, lactose was significantly associated with AD risk. CONCLUSIONS: Our study indicates that excessive total sugar intake was significantly associated with AD risk in women. Of six subtypes of sugar intake, lactose had a stronger impact on AD risk.

Toward 'seeing' critically: a Bayesian analysis of the impacts of a critical pedagogy.

Critical reflection supports enactment of the social roles of care, like collaboration and advocacy. We require evidence that links critical teaching approaches to future critically reflective practice. We thus asked: does a theory-informed approach to teaching critical reflection influence what learners talk about (i.e. topics of discussion) and how they talk (i.e. whether they talk in critically reflective ways) during subsequent learning experiences? Pre-clinical students (n = 75) were randomized into control and intervention conditions (8 groups each, of up to 5 interprofessional students). Participants completed an online Social Determinants of Health (SDoH) module, followed by either: a SDoH discussion (control) or critically reflective dialogue (intervention). Participants then experienced a common learning session (homecare curriculum and debrief) as outcome assessment, and another similar session one-week later. Blinded coders coded transcripts for what (topics) was said and how (critically reflective or not). We constructed Bayesian regression models for the probability of meaning units (unique utterances) being coded as particular what codes and as critically reflective or not (how). Groups exposed to the intervention were more likely, in a subsequent learning experience, to talk in a critically reflective manner (how) (0.096 [0.04, 0.15]) about similar content (no meaningful differences in what was said). This difference waned at one-week follow up. We showed experimentally that a particular critical pedagogical approach can make learners' subsequent talk, ways of seeing, more critically reflective even when talking about similar topics. This study offers the field important new options for studying historically challenging-to-evaluate impacts and supports theoretical assertions about the potential of critical pedagogies.

Combining adaptive expertise and (critically) reflective practice to support the development of knowledge, skill, and society.

Adaptive expertise (AE) and reflective practice (RP), two influential and resonant theories of professional expertise and practice in their own right, may further benefit health professions education if carefully combined. The current societal and systemic context is primed for both AE and RP. Both bodies of work position practitioners as agentive, learning continually and thoughtfully throughout their careers, particularly in order to manage unprecedented situations well. Similar on the surface, the roots and practices of AE and RP diverge at key junctures and we will focus on RP's movement toward critically reflective practice. The roots of AE and RP, and how they relate to or diverge from present-day applications matter because in health professions education, as in all education, paradigmatic mixing should be undertaken purposefully. This paper will explore the need for AE and RP, their shared commitments, distinctive histories, pedagogical possibilities both individually and combined, and next steps for maximizing their potential to positively impact the field. We argue that this exploration is urgently needed because both AE and RP hold much promise for improving health care and yet employing them optimally-whether alone or together-requires understanding and intent. We build an interprofessional education case situated in long-term care, throughout the paper, to demonstrate the potential that AE and RP might offer to health professions education individually and combined. This exploration comes just in time. Within the realities of uncertain practice emphasized by the pandemic, practitioners were also called to act in response to complex and urgent social movements. A combined AE and RP approach, with focus on critically reflective practice in particular, would potentially prepare professionals to respond effectively, compassionately, and equitably to future health and social crises and challenges.

Changes in Dietary Magnesium Intake and Risk of Type 2 Diabetes Mellitus in Middle School Students: Using Data from the HEALTHY Study.

BACKGROUND: The HEALTHY Study was a multicomponent school-based intervention, designed to prevent type 2 diabetes mellitus (T2DM) in middle-school students. OBJECTIVES: We examined whether the difference in dietary magnesium intake, BMI percentile, and plasma glucose and insulin concentrations from 6th to 8th grade were related in the intervention schools and in the control schools that participated in the HEALTHY Study. METHODS: A total of 2181 ethnically diverse students, from 11.3 to 13.7 y of age, with completed dietary records, BMI percentile, and plasma glucose and insulin concentrations at 6th and 8th grades were included. Dietary magnesium intake was self-reported using the Block Kids FFQ. A hierarchical multiple regression model was used to determine whether the differences in dietary magnesium intake, BMI percentile, and plasma glucose and insulin concentrations from 6th to 8th grades were related, while adjusting for dietary calcium intake and total energy intake. RESULTS: The difference in dietary magnesium intake was significantly related to changes in BMI percentile from 6th to 8th grade in intervention and in control schools [intervention: ß: -0.07; 95% CI: -0.58, -0.02; P = 0.03; R2 (regression coefficient effect size): 0.14; 95% CI for R2: 0.10, 0.17; control: ß: -0.08; 95% CI: -0.63, -0.09; P = 0.01; R2: 0.12; 95% CI for R2: 0.08, 0.15]. The difference in dietary magnesium intake was not related to plasma glucose and insulin concentrations in intervention and in control schools. CONCLUSIONS: We conclude that a multicomponent intervention was associated with reduced risk of T2DM, and that this association may be modulated, in part, by magnesium. The differences in dietary magnesium intake from 6th to 8th grade were negatively related to changes in BMI percentile among middle-school students.

Re-envisioning paradigms of education: towards awareness, alignment, and pluralism.

In this article we introduce a synthesis of education "paradigms," adapted from a multi-disciplinary body of literature and tailored to health professions education (HPE). Each paradigm involves a particular perspective on the purpose of education, the nature of knowledge, what knowledge is valued and included in the curriculum, what it means to learn and how learning is assessed, and the roles of teachers and learners in the learning process. We aim to foster awareness of how these different paradigms look in practice and to illustrate the importance of alignment between teaching, learning and assessment practices with paradigmatic values and assumptions. Finally, we advocate for a pluralistic approach that purposefully and meaningfully integrates paradigms of education, enhancing our ability to drive quality in HPE.

Dietary magnesium intake in relation to body mass index and glycemic indices in middle school students from the HEALTHY Study.

BACKGROUND: Data on dietary magnesium intake on the risk of type 2 diabetes mellitus (T2DM) among children and adolescents is limited. AIM: We examined whether dietary magnesium intake was related to body mass index (BMI) percentile, and glycemic indices at baseline and at end of the HEALTHY Study for both intervention and control schools. The HEALTHY Study was a multi-component, school-based intervention, to prevent T2DM in children and adolescents from 6th to 8th grades. METHODS: A secondary data analyses of 2181 ethnically diverse students with completed dietary records, BMI percentile, and plasma insulin and glucose concentrations at baseline (6th grade) and end of study (8th grade) were included from the HEALTHY Study. Dietary magnesium intake was self-reported using the Block Kids Food Frequency Questionnaire. A hierarchical multiple regression model was used to determine the relationships between dietary magnesium intake, BMI percentile, and glycemic indices at baseline and end of the HEALTHY Study, adjusting for magnesium intake from supplements, total energy intake, and fitness level. RESULTS: Dietary magnesium intake was related to BMI percentile at baseline and at end of the HEATHY Study (ß = -0.05, 95% CI = -0.02 to 0, p = 0.04; ß = -0.06, 95% CI = -0.02 to -0.003, p = 0.004); R 2 [regression coefficient effect size] = 0.03; R 2 = 0.06). Dietary magnesium intake was not related to plasma insulin and glucose concentrations at baseline and end of the HEALTHY Study. CONCLUSION: Dietary magnesium intake was inversely related to BMI percentile among middle school students from the HEALTHY Study. Research is required to evaluate the dose-response relationship between fruit and vegetable consumption (good sources of magnesium) and risk of T2DM in children and adolescents. This relationship also needs to be explored among different BMI categories.

Electromagnetically induced transparency in a mono-isotopic 167Er:7LiYF4 crystal below 1 Kelvin: microwave photonics approach.

Electromagnetically induced transparency allows for the controllable change of absorption properties, which can be exploited in a number of applications including optical quantum memory. In this paper, we present a study of the electromagnetically induced transparency in a 167Er:7LiYF4 crystal at low magnetic fields and ultra-low temperatures. The experimental measurement scheme employs an optical vector network analysis that provides high precision measurement of amplitude, phase and group delay and paves the way towards full on-chip integration of optical quantum memory setups. We found that sub-Kelvin temperatures are the necessary requirement for observing electromagnetically induced transparency in this crystal at low fields. A good agreement between theory and experiment is achieved by taking into account the phonon bottleneck effect.

Association of FKBP5 genotype with depressive symptoms in patients with coronary heart disease: a prospective study.

Depression and coronary heart disease (CHD) are prevalent and often co-occurring disorders. Both have been associated with a dysregulated stress system. As a central element of the stress system, the FKBP5 gene has been shown to be associated with depression. In a prospective design, this study aims to investigate the association of FKBP5 with depressive symptoms in CHD patients. N = 268 hospitalized CHD patients were included. Depressive symptoms were measured using the Hospital Anxiety and Depression Scale (HADS-D) at four time points (baseline, and after 1 month, 6 months, and 12 months). The functional FKBP5 single-nucleotide polymorphism (SNP) rs1360780 was selected for genotyping. Linear regression models showed that a higher number of FKBP5 C alleles was associated with more depressive symptoms in CHD patients both at baseline (p = 0.015) and at 12-months follow-up (p = 0.025) after adjustment for confounders. Further analyses revealed that this effect was driven by an interaction of FKBP5 genotype with patients' prior CHD course. Specifically, only in patients with a prior myocardial infarction or coronary revascularization, more depressive symptoms were associated with a higher number of C alleles (baseline: p = 0.046; 1-month: p = 0.026; 6-months: p = 0.028). Moreover, a higher number of C alleles was significantly related to a greater risk for dyslipidemia (p = .016). Our results point to a relevance of FKBP5 in the association of the two stress-related diseases depression and CHD.

Critically reflective practice and its sources: A qualitative exploration.

CONTEXT: Critical reflection may improve health professionals' performance of the social roles of care (eg collaboration) in indeterminate zones of practice that are ambiguous, unique, unstable or value-conflicted. Research must explore critical reflection in practice and how it is developed. In this study, we explored what critical reflection consisted of in a context known for indeterminacy, and to what sources participants attributed their critically reflective insights and approaches. METHODS: The study context was the interface between health care and education for children with chronic conditions or disabilities necessitating health-related recommendations and supports (eg accommodations or equipment) at school. We conducted a secondary analysis of 42 interview transcripts from an institutional ethnographic study involving health professionals, school-based educators and parents of children with chronic conditions or disabilities. We coded all transcripts for instances of critical reflection, moments that seemed to lack but could benefit from critical reflection, and participant-attributed sources of critically reflective insights. RESULTS: Critically reflective practice involved getting to know the other, valuing and leveraging different forms and sources of knowledge, identifying and communicating workarounds (ie strategies to circumvent imperfect systems), seeing inequities, and advocating as collaborators, not adversaries. Participants invariably attributed critically reflective insights to personal experiences such as former careers or close personal relationships. CONCLUSIONS: This study shows that personal experiences and connections inspire critically reflective views, and that being critically reflective is not a binary trait possessed (or not) by individuals. It is learnable through personally meaningful experiences. Health professions education could aim to preserve philosophical space for personal experience as a source of learning and integrate evidence-informed approaches to foster critically reflective practice.

When logics of learning conflict: an analysis of two workplace-based continuing education programs.

Educators, practitioners, and policy makers are calling for stronger connections between continuing education (CE) for professionals and the concerns of workplaces where these professionals work. This call for greater alignment is not unique to the health professions. Researchers within the field of higher education have long wrestled with the complexities of aligning professional learning and workplace concerns. In this study, we extend this critical line of inquiry to explore the possible conceptual intersections between two CE programs acting within a single healthcare organization. Both programs are concerned with improving patient care, primarily by changing the ways professionals think and talk with one another. However, the two programs have different historical origins: one in a workplace, the other within a university setting. Introducing the concept of "modes of ordering" as a way to analyze the curricula, we argue the programs are operating through separate logics of learning. We label these two modes of ordering: (1) learning as standardization and (2) learning as identification. Through our discussion, we explore how these different modes demand different roles for educators and participants. Ultimately, we argue that both have value. However, we also argue that educators require conceptual tools to sensitize them to the possibility of competing logics of learning and the subsequent implications for their practice as educators. In conclusion, we offer the metaphor of CE educator as choreographer, connecting concepts and practices within these logics in productive ways while continually navigating the various learning imperatives acting on professionals at any given time.

Protocols as curriculum? Learning health advocacy skills by working with transgender patients in the context of gender-affirming medicine.

Evidenced by leading journals in academic medicine, health professions education has taken up the call to advance equitable healthcare. One pressing area where gaps and inequities are apparent is transgender (trans) people's access to gender-affirming medicine such as hormones and surgeries. Reasons for the dire state of care include education gaps. While specific content knowledge has been identified as lacking in medical school curricula, less research has focused on the complex social practices required of clinicians and educators working in gender-affirming medicine, and how these skills are learned through practice. In order to inform health professions education in this key area of need, we conducted a study to better understand the social practices, and the learning that occurs therein, of gender-affirming medicine. We identified the work processes of 22 clinicians, clinician-educators, trans patients, and clinical care administrators with attention to how policies and protocols influenced practice, learning, and teaching. The results of our study elucidate: (1) that practicing of gender-affirming medicine is strictly dictated by standardized assessment protocols, which serve as a form of curriculum; and (2) how health professionals learn and teach health advocacy as a form of resistance to protocols identified as creating inequities. These findings suggest an opportunity to view protocols-and their inherent limitations-more deliberately as teaching and learning tools, specifically for learning advocacy.

Body Composition Changes after One Year in Professional Male Ice Hockey Players.

Body composition measurements remain one of the best objective ways to analyze tissue distribution in athletes. The purpose of this study was to establish an average body composition profile for professional male ice hockey players, assess the yearly fluctuations of body composition after a single season, and assess body composition changes among different positions. Body composition was measured using dual-energy X-ray absorptiometry in 36 professional male ice hockey players. Descriptive statistics were used to determine average values. A paired samples t-test was applied to determine differences over a one-year period. A one-way analysis of variance was used to determine differences between positions, at both time points. Alpha levels were set a priori at p<0.05. Significant increases were observed in percent body fat across time points for all positions (p=0.019). There were significant differences in percent body fat between positions played (p=0.012) after one year. We demonstrated that there was low variability among the different positions in professional male ice hockey players. Additionally, we observed how a single year minimally influences changes in body composition. More research is required to evaluate body composition in male ice hockey players.

Patients as teachers and arts-based reflection in surgical clerkship: A preliminary exploration.

BACKGROUND: Involving patients in medical education as teachers is not a novel approach, yet it has not been widely adopted by undergraduate surgical curricula in Canada. The Patients as Teachers initiative in surgery (PAT) program, with an arts-based reflection assignment, was developed for surgical clerks with the goals of emphasizing patient-centredness in surgical practice, humanistic aspects of medicine, and to counterbalance the commonplace emphasis on technical competency in surgery. METHODS: Qualitative data was collected exploring the question: What was the experience and impact of the PAT program on patient teachers and students? Patient teachers (n = 5) were invited to participate in one-on-one interviews and students (n = 46) were invited to participate in focus groups at the end of the program. RESULTS: Findings converged around two main themes: what students/patient teachers valued about the PAT program and what they perceived was learned. While patient teachers felt a sense of emotional healing and appreciated a chance to contribute to medical education, students valued having protected time to learn in depth from the patient teachers. Students also begrudgingly came to appreciate the arts-based reflection assignment. CONCLUSION: By bringing patient voice to the forefront and encouraging reflection, the PAT program emphasized to students the compassionate and humanistic side of surgical care. Future studies could examine the mechanisms by which learning occurs and long-term impacts.

The effect of carbohydrate and caffeine mouth rinsing on kicking performance in competitive Taekwondo athletes during Ramadan.

Mouth rinsing has been proposed as a strategy to minimize performance decrements during Ramadan. We investigated the effect of 4 weeks of Ramadan on kicking performance in 27 Taekwondo athletes performing weekly Taekwondo Anaerobic Intermittent Kick Tests (TAIKT). The effects of a placebo, 6.4% glucose and 6-mg/kg caffeine mouth rinses on TAIKT performance and perceived exertion were investigated before, during weekly training sessions, and after Ramadan in a counterbalanced, crossover design. Ramadan had a significant negative impact on the percentage of successful kicks in Week 1 of Ramadan (pre: 76.7±0.4%, Week 1: 69.9±3.2%). The percentage of successful kicks was significantly greater in the caffeine mouth rinse condition compared to the glucose and placebo conditions during the first 3 weeks of Ramadan (caffeine: 38.3±6.8%, glucose: 36.4±6.9%, placebo: 36.0±6.5%). Caffeine decreased perceived exertion during Ramadan (0.74-1.15 AU, p>0.05). Our results showed that Ramadan had a significant negative effect on repeated high-intensity kicking efforts that should be considered when training and competing. Additionally, there were significant positive effects of a caffeine mouth rinse in a sport-specific test. These data suggest that athletes can consider mouth rinsing as a strategy to enhance performance when undertaking training or competition during a period of privation.

Prevalence, 12-Month Prognosis, and Clinical Management Need of Depression in Coronary Heart Disease Patients: A Prospective Cohort Study.

BACKGROUND: Screening for depression in patients with coronary heart disease (CHD) remains controversial. There is limited data on the actual depression management need in routine care. The aim of this study was to examine the prevalence, treatment rates, prognosis, and management need of clinical and subclinical depression in CHD patients according to the American Heart Association recommendations and the National Institute for Health and Care Excellence (NICE) guideline "Depression in Adults with a Chronic Physical Health Problem". METHODS: Patients were recruited at 2 German university clinics between 2012 and 2014. Depressive disorders were assessed according to the DSM-IV and depressive symptom severity at baseline and during follow-up was evaluated with the Patient Health Questionnaire (PHQ-9). Depression management need was determined by the severity and longitudinal course of depression symptoms. RESULTS: Of 1,024 patients (19% women), 12% had clinical depression (depressive disorder) and 45% had subclinical depression (PHQ-9 score ≥5) at baseline. Among those with clinical depression, 46% were in treatment at least once during 12 months; 26% were continuously in treatment during follow-up. Depressive disorder and depressive symptoms were significant risk factor-adjusted predictors of the 12-months mortality (adjusted HR = 3.19; 95% CI 1.32-7.69, and adjusted HR = 1.09; 95% CI 1.02-1.16, respectively). Depressive symptoms persisted in 85% of the clinically depressed and in 47% of the subclinically depressed patients. According to current recommendations, 29% of all CHD patients would require depression management within 1 year. CONCLUSIONS: There is a need for enhanced recognition, referral, and continuous and improved clinical management of depression in CHD patients.

Swings between rotation and accretion power in a binary millisecond pulsar.

It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutionary stages, these binaries host a radio millisecond pulsar whose emission is powered by the neutron star's rotating magnetic field. This evolutionary model is supported by the detection of millisecond X-ray pulsations from several accreting neutron stars and also by the evidence for a past accretion disc in a rotation-powered millisecond pulsar. It has been proposed that a rotation-powered pulsar may temporarily switch on during periods of low mass inflow in some such systems. Only indirect evidence for this transition has hitherto been observed. Here we report observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation-powered radio pulsar. Within a few days after a month-long X-ray outburst, radio pulses were again detected. This not only shows the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.