Retinal endothelial function, physical fitness and cardiovascular risk: a diagnostic challenge

Introduction: Dynamic retinal vessel analysis (DVA) is a new non-invasive method to quantify microvascular endothelial dysfunction by flicker light-induced dilatation (FID). FID has been shown to be impaired in type 2 diabetes as well as heart failure. The aim of the study was to analyze FID in healthy active versus healthy sedentary and cardiovascular (CV) risk patients in addition to corresponding static vessel diameters. Methods: Thirty-one healthy active (HA, mean age 60 +/- 8 years), 33 healthy sedentary individuals (HS, 59 +/- 7 years) and 76 sedentary patients with increased CV risk (SR, 58 +/- 6 years) were included in this cross-sectional study. Group differences in CV risk factors and cardiorespiratory fitness, maximal arteriolar (ADmax) and venular (VDmax) dilatation as well as the arteriolar (AFarea) and venular (VFarea) area under the flicker curve were analyzed. The central retinal arteriolar and venular diameters were used to calculate the arteriolar-to-venular diameter ratio (AVR). Results: HS [ADmax = 3.5 (2.1)%; AFarea = 48.2 (31.9)%*s] showed higher FID compared to SR [ADmax = 2.7 (1.8)%, p = 0.021; AFarea = 34.5 (26.5)%*s, p = 0.006] and HA [AFarea = 32.8 (23.1)%*s, p = 0.029]. HA and SR did not significantly differ. HA had a higher AVR (0.87 +/- 0.05) compared to HS (0.83 +/- 0.04, p < 0.001) with further deterioration in SR (0.79 +/- 0.05, p < 0.001). Interestingly, 28 participants had impaired FID but normal AVR and 43 participants had normal FID but impaired AVR. Discussion: FID can differentiate between sedentary low and high risk individuals. However, FID in healthy active persons (HA) seemed impaired with a concomitant higher AVR. We postulate that lower FID in HA may be explained by predilatated arterioles and a reduced dilatation reserve. We recommend combination of FID with analysis of retinal vessel diameters to differentiate functional non-responders from manifest microvascular endothelial dysfunction and, thereby, improve microvascular risk stratification in a personalized medicine approach. Clinical Trial Registration: ClinicalTrials.gov: NCT02796976 (https://clinicaltrials.gov/ct2/show /NCT02796976)

The acute effects of aerobic exercise on sleep in patients with unipolar depression: a randomized controlled trial

Study Objectives Insomnia increases the risk of negative disease trajectory, relapse, and suicide in patients with depression. We aimed at investigating the effects of a single bout of aerobic exercise, performed after 02:00 pm, on the subsequent night’s sleep in patients with depression. Methods The study was designed as a two-arm parallel-group, randomized, outcome assessor-blinded, controlled, superiority trial. Patients between 18 and 65 years of age with a primary diagnosis of unipolar depression were included. The intervention was a single 30-minute bout of moderate aerobic exercise. The control group sat and read for 30 minutes. The primary outcome was sleep efficiency measured by polysomnography. Secondary outcomes were other polysomnographic variables, subjective sleep quality, daytime sleepiness, mood states, and adverse events. Results Ninety-two patients were randomized to the exercise (N = 46) or control group (N = 46). There were no clinically relevant differences at baseline. Intent-to-treat analysis ANCOVA of follow-up sleep efficiency, adjusted for baseline levels and minimization factors, did not detect a significant effect of the allocation (β = −0.93, p = 0.59). There was no evidence for significant differences between both groups in any other objective or subjective sleep outcomes, daytime sleepiness, or adverse events. The intervention had an immediate positive effect on mood states, including depressiveness (β = −0.40, p = 0.003). Conclusions This is the first trial to study the effects of a single bout of aerobic exercise on sleep in patients with depression to the best of our knowledge. Aerobic exercise had no effect on sleep efficiency but had a strong beneficial effect on mood and did not increase adverse outcomes. These results add to the growing body of evidence that, contrary to sleep hygiene recommendations, exercise after 02:00 pm is not detrimental for sleep. Clinical Trial Registration Clinicaltrials.gov, https://clinicaltrials.gov/ct2/show/NCT03673397. Protocol registered on September 17, 2018

In Athletes, the Diurnal Variations in Maximum Oxygen Uptake Are More Than Twice as Large as the Day-to-Day Variations

In competitive sports any substantial individual differences in diurnal variations in maximal performance are highly relevant. Previous studies have exclusively focused on how the time of day affects performance and disregarded the maximal individual diurnal variation of performance. Thus, the aims of this study were (1) to investigate the maximum diurnal variation in maximum oxygen uptake (VO2max), (2) to compare the diurnal variation of VO2max during the day to the day-to-day variation in VO2max, and (3) to investigate if there is a time-of-day effect on VO2max. Ten male and seven female athletes (mean VO2max: 58.2 ± 6.9 ml/kg/min) performed six maximal cardiopulmonary exercise tests including a verification-phase at six different times of the day (i.e., diurnal variation) and a seventh test at the same time the sixth test took place (i.e., day-to-day variation). The test times were 7:00, 10:00, 13:00, 16:00, 19:00, and 21:00. The order of exercise tests was the same for all participants to ensure sufficient recovery but the time of day of the first exercise test was randomized. We used paired t-tests to compare the nadir and peak of diurnal variations, day-to-day variations and the difference between diurnal and day-to-day variations. The mean difference in VO2max was 5.0 ± 1.9 ml/kg/min (95% CI: 4.1, 6.0) for the diurnal variation and 2.0 ± 1.0 ml/kg/min (95% CI: 1.5, 2.5) for the day-to-day variation. The diurnal variation was significantly higher than the day-to-day variation with a mean difference of 3.0 ± 2.1 ml/kg/min (95% CI: 1.9, 4.1). The linear mixed effects model revealed no significant differences in VO2max for any pairwise comparison between the different times of the day (all p &gt; 0.11). This absence of a time-of-day effect is explained by the fact that peak VO2max was achieved at different times of the day by different athletes. The diurnal variations have meaningful implications for competitive sports and need to be considered by athletes. However, the results are also relevant to research. To increase signal-to-noise-ratio in intervention studies it is necessary to conduct cardiopulmonary exercise testing at the same time of the day for pre- and post-intervention exercise tests

Should sports and exercise medicine be taught in the Swiss undergraduate medical curricula? A survey among 1764 Swiss medical students

Objectives The global lack of sports and exercise medicine (SEM) teaching at medical schools contrasts with evidence that physical activity (PA) plays a major role in preventing and treating non-communicable diseases (NCDs). The aims of this study were to (a) examine whether Swiss medical students are expected to acquire SEM-related skills and knowledge, (b) systematically reviewed SEM teaching in the Swiss undergraduate medical curricula, (c) assess if Swiss medical students are aware of SEM and (d) whether they would like SEM to be included in their curricula. Methods Two authors independently screened the 'Principal Relevant Objectives and Framework for Integrative Learning and Education in Switzerland' (PROFILES) for SEM-related learning objectives and reviewed the curricula. 7708 Swiss medical students were invited to participate in an online survey. Results 32 SEM-related learning objectives were identified in PROFILES with 20 of them linked to PA. Four of eight Swiss medical schools display limited mandatory SEM teachings. 1764 students participated in the survey (482.0% of the necessary sample size, 22.9% of all Swiss medical students). One in two students knew that SEM includes preventing and treating NCDs. Almost 95% of the participants would like SEM to be included in the curricula. Conclusion Despite its inclusion in PROFILES and comprehensive evidence that SEM should be taught at medical schools, this is scarcely the case in Switzerland. Swiss medical students have limited understanding of SEM, but are keen to have it included in the curricula. This study highlights the need for more comprehensive SEM teaching at Swiss medical schools

Cardiorespiratory fitness and development of childhood cardiovascular risk: The EXAMIN YOUTH follow-up study

Background: Obesity- and hypertension-related cardiovascular (CV) risk has been shown to originate in childhood. Higher body mass index (BMI) and blood pressure (BP) have been associated with increased large artery stiffness and a lower microvascular arteriolar-to-venular diameter ratio (AVR) in children. This study aimed to investigate the association of cardiorespiratory fitness (CRF) with development of BMI, BP and vascular health during childhood.Methods: In our prospective cohort study, 1,171 children aged 6–8 years were screened for CRF, BMI, BP, retinal vessel diameters and pulse wave velocity using standardized protocols. Endurance capacity was assessed by 20 m shuttle run test. After 4 years, all parameters were assessed in 664 children using the same protocols.Results: Children with a higher CRF at baseline developed a significantly lower BMI (β [95% CI] −0.09 [−0.11 to −0.06] kg/m2, p &lt; 0.001), a lower systolic BP (β [95% CI] −0.09 [−0.15 to −0.03] mmHg, p = 0.004) and a higher AVR (β [95% CI] 0.0004 [0.00004 to 0.0007] units, p = 0.027) after 4 years. The indirect association of CRF with development of retinal arteriolar diameters was mediated by changes in BMI.Conclusion: Our results identify CRF as a key modulator for the risk trajectories of BMI, BP and microvascular health in children. Obesity-related CV risk has been shown to track into adulthood, and achieving higher CRF levels in children may help counteract the development of CV risk and disease not only in pediatric populations, but may also help reduce the burden of CVD in adulthood.Registration:http://www.clinicaltrials.gov/ (NCT02853747)

Association of accelerometry-based and self-reported physical activity with cardiovascular risk in South African children

The burden of non-communicable diseases is increasing, with risk factors emerging early in life. Physical activity reduces cardiovascular risk, but limited evidence exists for children from lower-income countries and mostly relies on self-reported methods that might be inaccurate and biased. We aimed to compare self-reported and accelerometer-measured physical activity in relation to cardiovascular risk markers in children from underserved communities in South Africa. We analysed cross-sectional data from 594 children aged 8 to 13. Physical activity was measured via accelerometry and the Physical Activity Questionnaire for Older Children (PAQ-C). Correlation analyses and linear regression models examined the relationship between accelerometer-measured and self-reported physical activity and their association with cardiovascular risk markers (body mass index, blood pressure, blood lipid profile and glycated haemoglobin). Results show a positive but weak correlation between PAQ-C scores and accelerometer-measured moderate-to-vigorous physical activity (MVPA). MVPA was inversely associated with body mass index, whilst sedentary behaviour correlated positively with lipid levels. PAQ-C scores were inversely associated with systolic blood pressure. The comparison of self-reported and accelerometer-measured physical activity in children from Gqeberha, South Africa, revealed inconsistencies in their correlation and association with cardiovascular risk markers. Accelerometry provided a more accurate cardiovascular risk estimation than PAQ-C, although associations were weak. Further, longitudinal studies should investigate the predictive power of both methodologies. These findings inform researchers and public health practitioners in the choice of method for physical activity appraisal beyond practical considerations, especially when combined with cardiovascular risk and in lower-income settings. Significance: We explore two widely used methods to assess physical activity levels in children. By comparing both methods, we expose inconsistencies in their correlation and association with cardiovascular risk markers. These data can guide researchers and public health practitioners in the use of one method beyond practical considerations. Whilst this work focuses on children from marginalised areas of South Africa, the issues explored are of relevance to other lower-income settings. Open data set: https://doi.org/10.5281/zenodo.721714

Investigating the circulating sphingolipidome response to a single high-intensity interval training session within healthy females and males in their twenties (SphingoHIIT): Protocol for a randomised controlled trial [version 2; peer review: 2 approved]

Introduction: Growing scientific evidence indicates that sphingolipids predict cardiometabolic risk, independently of and beyond traditional biomarkers such as low-density lipoprotein cholesterol. To date, it remains largely unknown if and how exercise, a simple, low-cost, and patient-empowering modality to optimise cardiometabolic health, influences sphingolipid levels. The SphingoHIIT study aims to assess the response of circulating sphingolipid species to a single session of high-intensity interval training (HIIT). Methods: This single-centre randomised controlled trial (RCT) will last 11 days per participant and aim to include 32 young and healthy individuals aged 20-29 (50% females). Participants will be randomly allocated to the HIIT (n= 16) or control groups (physical rest, n= 16). Participants will self-sample fasted dried blood spots for three consecutive days before the intervention (HIIT versus rest) to determine baseline sphingolipid levels. Dried blood spots will also be collected at five time points (2, 15, 30, 60min, and 24h) following the intervention (HIIT versus rest). To minimise the dietary influence, participants will receive a standardised diet for four days, starting 24 hours before the first dried blood sampling. For females, interventions will be timed to fall within the early follicular phase to minimise the menstrual cycle's influence on sphingolipid levels. Finally, physical activity will be monitored for the whole study duration using a wrist accelerometer. Ethics and dissemination: The Ethics Committee of Northwest and Central Switzerland approved this protocol (ID 2022–00513). Findings will be disseminated in scientific journals and meetings. Trial Registration The trial was registered on www.clinicaltrials.gov (NCT05390866, https://clinicaltrials.gov/ct2/show/NCT05390866) on May 25, 2022

Should sports and exercise medicine be taught in the Swiss undergraduate medical curricula? A survey among 1764 Swiss medical students

ObjectivesThe global lack of sports and exercise medicine (SEM) teaching at medical schools contrasts with evidence that physical activity (PA) plays a major role in preventing and treating non-communicable diseases (NCDs). The aims of this study were to (a) examine whether Swiss medical students are expected to acquire SEM-related skills and knowledge, (b) systematically reviewed SEM teaching in the Swiss undergraduate medical curricula, (c) assess if Swiss medical students are aware of SEM and (d) whether they would like SEM to be included in their curricula.MethodsTwo authors independently screened the ‘Principal Relevant Objectives and Framework for Integrative Learning and Education in Switzerland’ (PROFILES) for SEM-related learning objectives and reviewed the curricula. 7708 Swiss medical students were invited to participate in an online survey.Results32 SEM-related learning objectives were identified in PROFILES with 20 of them linked to PA. Four of eight Swiss medical schools display limited mandatory SEM teachings. 1764 students participated in the survey (482.0% of the necessary sample size, 22.9% of all Swiss medical students). One in two students knew that SEM includes preventing and treating NCDs. Almost 95% of the participants would like SEM to be included in the curricula.ConclusionDespite its inclusion in PROFILES and comprehensive evidence that SEM should be taught at medical schools, this is scarcely the case in Switzerland. Swiss medical students have limited understanding of SEM, but are keen to have it included in the curricula. This study highlights the need for more comprehensive SEM teaching at Swiss medical schools

Oxygen uptake during mini trampoline exercise in normal-weight, endurance-trained adults and in overweight-obese, inactive adults: A proof-of-concept study

To examine cardiorespiratory exertion during mini trampoline exercises of different intensities in both endurance-trained athletes and overweight-obese adults.; Physically healthy participants (Group A: normal-weight, endurance-trained athletes; Group B: inactive, overweight-obese adults) participated in two measurement appointments and three training sessions in between appointments, in which participants familiarized themselves with the use of the mini trampoline and the execution of the exercises. The primary outcome was the ⩒O; 2peak; for each of the six mini trampoline exercises relative to the ⩒O; 2peak; as established during an all-out exercise test on a bike ergometer during the first measurement appointment. Secondary outcomes were average ⩒O; 2; as well as maximum and average heart rate.; The six mini trampoline exercises generated ⩒O; 2peak; values between 42% and 81% in the endurance-trained athletes and between 58% and 87% in the overweight-obese participants, both in relation to the bike ergometer ⩒O; 2peak; . Average ⩒O; 2; values ranged from 35% to 69% (endurance-trained athletes) and from 48% to 71% (overweight-obese participants), depending on exercise. Average heart rate likewise lay in a range that can be categorized as moderate-to-vigorous aerobic exercise for both groups. A moderate-to-strong correlation (0.658 to 0.875, depending on exercise) between bike ergometer ⩒O; 2peak; and mini trampoline ⩒O; 2peak; was found for all six exercises.; Mini trampoline exercise has the potential to produce training intensities that concur with established exercise guidelines. The exercise intensity is self-adjusting and allows for an effective and safe workout for different users with a wide range of fitness levels