Pulmonary Rehabilitation for People With Persistent Symptoms After COVID-19.

TOPIC IMPORTANCE: COVID-19 can cause ongoing and persistent symptoms (such as breathlessness and fatigue) that lead to reduced functional capacity. There are parallels in symptoms and functional limitations in adults with post-COVID symptoms and adults with chronic respiratory diseases. Pulmonary rehabilitation is a key treatment for adults with chronic respiratory diseases, with the aims to improve symptom management and increase functional capacity. Given the similarities in presentation and aims, a pulmonary rehabilitation program may be optimal to meet the needs of those with ongoing symptoms after COVID-19. REVIEW FINDINGS: Aerobic and strength training has shown benefit for adults living with long COVID, although there is little evidence on structured education in this population. Breathing pattern disorder is common in adults with long COVID, and considerations on treatment before rehabilitation, or alongside rehabilitation, are necessary. Considerations on postexertional malaise are important in this population, and evidence from the chronic fatigue syndrome literature supports the need for individualization of exercise programs, and considerations for those who have an adverse reaction to activity and/or exercise. SUMMARY: This narrative review summarizes the current evidence on pulmonary rehabilitation programs in a long-COVID population. Where the evidence is lacking in long COVID the supporting evidence of these programs in chronic respiratory diseases has highlighted the importance of aerobic and strength training, considerations for fatigue, potential mechanisms for immunology improvement, and management of breathing pattern disorders in these programs.

Evaluating the effect of a digital health intervention to enhance physical activity in people with chronic kidney disease (Kidney BEAM): a multicentre, randomised controlled trial in the UK.

BACKGROUND: Remote digital health interventions to enhance physical activity provide a potential solution to improve the sedentary behaviour, physical inactivity, and poor health-related quality of life that are typical of chronic conditions, particularly for people with chronic kidney disease. However, there is a need for high-quality evidence to support implementation in clinical practice. The Kidney BEAM trial evaluated the clinical effect of a 12-week physical activity digital health intervention on health-related quality of life. METHODS: In a single-blind, randomised controlled trial conducted at 11 centres in the UK, adult participants (aged ≥18 years) with chronic kidney disease were recruited and randomly assigned (1:1) to the Kidney BEAM physical activity digital health intervention or a waiting list control group. Randomisation was performed with a web-based system, in randomly permuted blocks of six. Outcome assessors were masked to treatment allocation. The primary outcome was the difference in the Kidney Disease Quality of Life Short Form version 1.3 Mental Component Summary (KDQoL-SF1.3 MCS) between baseline and 12 weeks. The trial was powered to detect a clinically meaningful difference of 3 arbitrary units (AU) in KDQoL-SF1.3 MCS. Outcomes were analysed by an intention-to-treat approach using an analysis of covariance model, with baseline measures and age as covariates. The trial was registered with ClinicalTrials.gov, NCT04872933. FINDINGS: Between May 6, 2021, and Oct 30, 2022, 1102 individuals were assessed for eligibility, of whom 340 participants were enrolled and randomly assigned to the Kidney BEAM intervention group (n=173) or the waiting list control group (n=167). 268 participants completed the trial (112 in the Kidney BEAM group and 156 in the waiting list control group). All 340 randomly assigned participants were included in the intention-to treat population. At 12 weeks, there was a significant improvement in KDQoL-SF.13 MCS score in the Kidney BEAM group (from mean 44·6 AU [SD 10·8] at baseline to 47·0 AU [10·6] at 12 weeks) compared with the waiting list control group (from 46·1 AU [10·5] to 45·0 AU [10·1]; between-group difference of 3·1 AU [95% CI 1·8-4·4]; p<0·0001). INTERPRETATION: The Kidney BEAM physical activity platform is an efficacious digital health intervention to improve mental health-related quality of life in patients with chronic kidney disease. These findings could facilitate the incorporation of remote digital health interventions into clinical practice and offer a potential intervention worthy of investigation in other chronic conditions. FUNDING: Kidney Research UK.

Adipose inflammation: South Asian ethnicity and central obesity are independently associated with higher immune cell recruitment to adipose-specific media: A pilot study in men.

A South Asian (SA) cardiovascular phenomenon exists whereby SAs have excess burden of cardiovascular disease (CVD) despite having low prevalence of recognized CVD risk factors. The aim of the current study was to determine whether perturbations in monocyte biology contribute to this phenomenon via higher circulating cell numbers, a more pro-inflammatory phenotype, and higher transmigration and adhesion. Adhesion is linked to vascular inflammation whereas transmigration is linked to tissue inflammation. SA men with (N = 10; SAs with central obesity [CO-SA]) and without (N = 10; lean SA [LE-SA]) central obesity, plus White European counterparts (N = 10; white Europeans with central obesity [CO-WE], N = 10; lean white Europeans [LE-WE]) participated. An ex vivo assay mimicking blood flow dynamics coupled to flow cytometry determined the adhesion and transmigration of monocyte subsets toward chemokine-rich media cultured from pre-adipocytes (absolute responses). Migration and adhesion were also standardized for differences in numbers of circulating monocytes between participants (relative responses). Metabolic and inflammatory markers were assessed. SAs had higher absolute (but not relative) adhesion and migration of monocytes than WEs. Central obesity was associated with higher absolute and relative adhesion and migration of monocytes. SAs had higher concentrations of all monocyte subsets compared with WEs coinciding with adverse cardiovascular-inflammatory profiles. LE-SAs had similar monocyte concentrations, transmigration, and adhesion compared with CO-WEs, corresponding with similar cardiovascular-inflammatory profiles. The study provides novel evidence for higher monocyte counts associated with higher transmigration and adhesion in SA compared with WE men. Importantly, similar monocyte biology and cardiovascular-inflammatory profiles were seen in LE-SAs compared with CO-WEs, which may contribute to the higher risk of CVD at lower body mass index experienced by SAs.

Mechanically demanding eccentric exercise increases nuclear factor erythroid 2-related factor 2 activity in human peripheral blood mononuclear cells.

PRE-REGISTRATION NUMBER: osf.io/kz37g.

Perceptions and Experiences of High-Intensity Interval Training in Kidney Transplant Recipients: A Big HIIT?

High-intensity interval training (HIIT) is considered a novel and time-efficient method to reduce cardiovascular disease risk, a leading cause of mortality in kidney transplant recipients. However, research in this population is severely limited. The aim of this study was to understand kidney transplant recipients' perceptions and experiences of HIIT and their readiness to participate in HIIT. Individual, semi-structured interviews were conducted in adults with a kidney transplant (n = 13; 53±13 years). Interviews were audiorecorded, transcribed verbatim, and subjected to framework analysis. Overall, participants had a good knowledge of HIIT and were open to participation. Acknowledgment of the superior benefits to cardiovascular, mental, and general health, as well as the lower time commitment, were all motivators for participation. There were some heightened concerns around damaging the kidney and 'knowing your limits. Personalization, physician's approval, and supervision were all important factors in participation. This study provides evidence that HIIT would be, in principle, largely accepted by recipients of a kidney transplant. However, several considerations are also identified in the present study, which would be essential to the success of any future efficacy trial or rehabilitation program.

Effect of Acute Walking on Endothelial Function and Postprandial Lipemia in South Asians and White Europeans.

INTRODUCTION: South Asians (SAs) have an elevated risk of cardiovascular disease (CVD) compared with White Europeans (WEs). Postprandial endothelial function (flow-mediated dilatation (FMD%)) in SA women and SA men with central obesity has not been investigated. Research in other populations has highlighted that a 1% higher FMD% is associated with a ~13% lower risk of future CVD events. We investigated whether FMD% and lipemia, two markers for CVD risk, were higher in SAs versus WEs, whether walking improved FMD% and lipemia, and if there were ethnic differences in the response. METHODS: Lean premenopausal women (study 1; 12 SA, 12 WE) and men with central obesity (study 2; 15 SA, 15 WE) completed two 2-d trials. On day 1, participants walked for 60 min at 60% of their peak oxygen uptake or rested. On day 2, participants rested and consumed two high-fat meals over 8 h. Repeated ultrasound assessments of endothelial function and venous blood samples for CVD risk markers were taken. RESULTS: Compared with WEs, SAs had lower postprandial FMD% (study 1, -1.32%; study 2, -0.54%) and higher postprandial triacylglycerol concentrations (study 1, 0.31 mmol·L -1 ·h -1 ; study 2, 0.55 mmol·L -1 ·h -1 ). Walking improved postprandial FMD% (study 1, 1.12%; study 2, 0.94%) and resulted in no significant change or small reductions in postprandial triacylglycerol concentrations (study 1, -0.01 mmol·L -1 ·h -1 ; study 2, -0.25 mmol·L -1 ·h -1 ). Exercise-induced changes in FMD% and triacylglycerol were consistent between ethnic groups. CONCLUSIONS: Walking mitigated the adverse postprandial effect of a high-fat diet on FMD% to a similar extent in SA and WE women and men, even with no/small improvements in triacylglycerol. This study highlights the importance of exercise to clinically improve FMD% in SAs and WEs.

Exercise and chronic kidney disease: potential mechanisms underlying the physiological benefits.

Increasing evidence indicates that exercise has beneficial effects on chronic inflammation, cardiorespiratory function, muscle and bone strength and metabolic markers in adults with chronic kidney disease (CKD), kidney failure or kidney transplants. However, the mechanisms that underlie these benefits have received little attention, and the available clinical evidence is mainly from small, short-duration (<12 weeks) exercise intervention studies. The available data, mainly from patients with CKD or on dialysis, suggest that exercise-mediated shifts towards a less inflammatory immune cell profile, enhanced activity of the NRF2 pathway and reduced monocyte infiltration into adipose tissue may underlie improvements in inflammatory biomarkers. Exercise-mediated increases in nitric oxide release and bioavailability, reduced angiotensin II accumulation in the heart, left ventricular remodelling and reductions in myocardial fibrosis may contribute to improvements in left ventricular hypertrophy. Exercise stimulates an anabolic response in skeletal muscle in CKD, but increases in mitochondrial mass and satellite cell activation seem to be impaired in this population. Exercise-mediated activation of the canonical wnt pathway may lead to bone formation and improvements in the levels of the bone-derived hormones klotho and fibroblast growth factor 23 (FGF23). Longer duration studies with larger sample sizes are needed to confirm these mechanisms in CKD, kidney failure and kidney transplant populations and provide evidence for targeted exercise interventions.

High grip strength attenuates risk of severe COVID-19 in males but not females with obesity: A short communication of prospective findings from UK Biobank.

We examined the joint associations of BMI category and grip strength tertile with risk of severe COVID-19 (inpatient COVID-19 or COVID-19 mortality) in 327 500 UK Biobank participants. Compared to normal-weight males with high grip strength, the odds ratio (95 % confidence interval) for males with obesity with low grip strength was 2.39 (1.59-3.60), but 1.52 (0.98-2.35) for males with obesity with a high grip strength. A higher grip strength did not appear to be associated with lower risk of severe COVID-19 in females. Muscle mass and strength development should be considered as a means to reduce risk of severe COVID-19 for males with obesity.

The effect of COVID rehabilitation for ongoing symptoms Post HOSPitalisation with COVID-19 (PHOSP-R): protocol for a randomised parallel group controlled trial on behalf of the PHOSP consortium.

INTRODUCTION: Many adults hospitalised with COVID-19 have persistent symptoms such as fatigue, breathlessness and brain fog that limit day-to-day activities. These symptoms can last over 2 years. Whilst there is limited controlled studies on interventions that can support those with ongoing symptoms, there has been some promise in rehabilitation interventions in improving function and symptoms either using face-to-face or digital methods, but evidence remains limited and these studies often lack a control group. METHODS AND ANALYSIS: This is a nested single-blind, parallel group, randomised control trial with embedded qualitative evaluation comparing rehabilitation (face-to-face or digital) to usual care and conducted within the PHOSP-COVID study. The aim of this study is to determine the effectiveness of rehabilitation interventions on exercise capacity, quality of life and symptoms such as breathlessness and fatigue. The primary outcome is the Incremental Shuttle Walking Test following the eight week intervention phase. Secondary outcomes include measures of function, strength and subjective assessment of symptoms. Blood inflammatory markers and muscle biopsies are an exploratory outcome. The interventions last eight weeks and combine symptom-titrated exercise therapy, symptom management and education delivered either in a face-to-face setting or through a digital platform ( www.yourcovidrecovery.nhs.uk ). The proposed sample size is 159 participants, and data will be intention-to-treat analyses comparing rehabilitation (face-to-face or digital) to usual care. ETHICS AND DISSEMINATION: Ethical approval was gained as part of the PHOSP-COVID study by Yorkshire and the Humber Leeds West Research NHS Ethics Committee, and the study was prospectively registered on the ISRCTN trial registry (ISRCTN13293865). Results will be disseminated to stakeholders, including patients and members of the public, and published in appropriate journals. Strengths and limitations of this study • This protocol utilises two interventions to support those with ongoing symptoms of COVID-19 • This is a two-centre parallel-group randomised controlled trial • The protocol has been supported by patient and public involvement groups who identified treatments of symptoms and activity limitation as a top priority.

Sedentary behaviour, but not moderate-to-vigorous physical activity, is associated with respiratory responses to acute psychological stress.

BACKGROUND: Acute psychological stress induces respiratory responses, and stress-induced respiratory changes can be used to non-invasively reflect metabolic regulation. Respiratory and cardiovascular responses to stress are both driven by sympathetic mechanisms. Higher volumes of sedentary behaviour and lower volumes of physical activity are associated with elevated sympathetic tone and larger cardiovascular responses to stress. The aim of this study was to test whether these associations translate to measures of respiratory stress reactivity. METHODS: Daily hours of sedentary behaviour (thigh-mounted activPAL) and moderate-to-vigorous physical activity (MVPA; wrist-mounted ActiGraph) were assessed across seven days. Breath-by-breath respiratory (e.g., breathing frequency [BF], end-tidal carbon dioxide partial pressure [PetCO2], carbon dioxide output [V̇CO2] and respiratory exchange ratio [RER]) responses to an 8-min Paced Auditory Serial Addition Test were then measured using a Cortex MetaLyzer3B. RESULTS: Healthy participants (N = 61, mean age ± SD = 25.7 ± 8.9 years) recorded high volumes of sedentary behaviour (9.96 ± 1.48 h/day) and MVPA (1.70 ± 0.71 h/day). In adjusted models (with the inclusion of sedentary behaviour, MVPA, and other a priori selected covariates) hours of daily sedentary behaviour were associated with baseline to stress changes in BF (Β = 0.695, 95% CI = 0.281 - 1.109, p = .014), VT (Β = -0.042, 95% CI = -0.058 - -0.026, p = .014), PetCO2 (Β = -0.537, 95% CI = -0.829 - -0.245, p = .014), V̇CO2 (Β = -0.008, 95% CI = -0.014 - -0.003, p = .030), and RER (Β = -0.013, 95% CI = -0.021 - -0.005, p = .022). Daily hours of MVPA were not linked with respiratory responses to stress. DISCUSSION: Sedentary behaviour, but not MVPA, is associated with respiratory stress reactivity. Future work should untangle the underlying mechanisms of these findings and explore the consequences for cardiometabolic disease.

Inactivity and obesity: consequences for macrophage-mediated inflammation and the development of cardiometabolic disease.

Obesity and dyslipidaemia are strongly associated with the development of cardiometabolic diseases including CVD, stroke, type 2 diabetes, insulin resistance and non-alcoholic fatty liver disease. While these conditions are preventable, they are leading causes of mortality globally. There is now overwhelming clinical and experimental evidence that these conditions are driven by chronic systemic inflammation, with a growing body of data suggesting that this can be regulated by increasing levels of physical activity and reducing sedentary time. In this review we address the role of macrophage-mediated inflammation on the development of cardiometabolic diseases in individuals with overweight and obesity and how reducing sedentary behaviour and increasing physical activity appears to lessen these pro-inflammatory processes, reducing the risk of developing cardiometabolic diseases. While loss of subcutaneous and visceral fat mass is important for reducing chronic systemic inflammation, the mediating effects of increasing physical activity levels and lowering sedentary time on the development of inflamed adipose tissue also occur independently of changes in adiposity. The message that weight loss is not necessary for the benefits of physical activity in lowering chronic inflammation and improving health should encourage those for whom losing weight is difficult. Additionally, while the health benefits of meeting the recommended physical activity guidelines are clear, simply moving more appears to lower chronic systemic inflammation. Reducing sitting time and increasing light physical activity may therefore provide an alternative, more approachable manner for some with overweight and obesity to become more active, reduce chronic inflammation and improve cardiometabolic health.

Frequently Interrupting Prolonged Sitting With Light Body-Weighted Resistance Activity Alters Psychobiological Responses to Acute Psychological Stress: A Randomized Crossover Trial.

BACKGROUND: Uninterrupted prolonged sitting and exaggerated psychobiological reactivity to acute psychological stress are associated with increased risk of cardiovascular disease (CVD). Breaking up prolonged sitting with frequent, short bouts of light-intensity physical activity acutely lowers CVD risk markers under resting conditions. PURPOSE: To examine whether frequent interruptions to prolonged sitting with body-weighted resistance activity can acutely lower systolic blood pressure (SBP; primary outcome) and other cardiovascular (CV), inflammatory, and cortisol (secondary outcomes) responses to acute psychological stress. METHODS: This randomized crossover trial included 17 sedentary participants (9 men; mean ± SD age; 24.0 ± 0.5 years) who completed two conditions: (i) interrupting 4 hr of sitting with 4 min of light body-weighted resistance activity every 30-min (BREAK), and (ii) 4 hr of uninterrupted sitting (SIT). Following the BREAK and SIT intervention windows, CV, inflammatory, and cortisol markers were measured at rest, during stress tasks (8-min Paced Auditory Serial Addition Test [PASAT] and 3-min cold pressor [CP]), and 45-min recovery periods. RESULTS: There were main effects of time for CV parameters (SBP, diastolic blood pressure, heart rate, cardiac output, and total peripheral resistance [all p < .001]), inflammatory markers (interleukin-6 [IL-6]), and cortisol (p < .05) in response to stress. Time-by-condition interaction effects revealed that in the BREAK-condition there was lower SBP during immediate recovery from the CP (mean {95% confidence interval [CI]}: 127.2 [121.3, 133.4] vs 133.4 [125.5, 141.7] mmHg; p = .020), higher concentrations of plasma IL-6 45-min post-PASAT (2.70 [1.97, 3.70] vs 1.71 [1.32, 2.22] pg/mL; p = .010), and larger (nonsignificant) salivary cortisol concentrations 8-min post-CP (6.29 [4.60, 8.58] vs 3.97 [3.16, 4.99] nmol/L; p = .079). CONCLUSIONS: Interrupting prolonged sitting with frequent bouts of light intensity body-weighted resistance activity alters psychobiological responses to acute psychological stress. Further research should explore the longer-term implications for CVD risk.

Sitting for long periods without interruption and the way in which we physically respond to short-term psychological stress are linked to heart disease risk. Breaking up sitting with short, frequent bouts of light activity can lower heart disease risk but how this may improve how we respond to stress is unknown. Our study investigated if interruptions to prolonged sitting with body-weighted resistance activity lowered changes seen under stress such as changes in blood pressure (BP) and inflammation. Seventeen participants undertook two testing sessions. One session interrupted 4 hr of sitting with 4-min of light activity every 30-min, and the other session was 4 hr of uninterrupted sitting. After each session, participants did two stress tasks: one math-based task and one where feet were submerged in cold water. The changes in BP and inflammation to stress were measured. We found when breaking-up sitting time with activity, BP was lower after the cold-water task compared to when people did not break up their sitting. In summary, breaking up sitting with frequent bouts of light activity may influence how we respond to short-term stress, but future research needs to explore what these short-term changes mean for the longer-term risks of heart disease.

The joint associations of physical activity and TV viewing time with COVID-19 mortality: An analysis of UK Biobank.

We used logistic regression to investigate the joint associations of physical activity level (high: ≥3000 MET-min/week, moderate: ≥600 MET-min/week, low: not meeting either criteria) and TV viewing time (low: ≤1 h/day, moderate: 2-3 h/day, high: ≥4 h/day) with COVID-19 mortality risk in UK Biobank. Additional models were performed with adjustment for body mass index (BMI) and waist circumference. Within the 373, 523 included participants, there were 940 COVID-19 deaths between 16 March 2020 and 12 November 2021. Compared to highly active individuals with a low TV viewing time, highly active individuals with a high TV viewing time were at significantly higher risk of COVID-19 mortality (odds ratio = 1.54, 95% confidence interval = 1.11-2.15). However, the greatest risk was observed for the combination of a low physical activity level and a high TV viewing time (2.29, 1.63-3.21). After adjusting for either BMI or waist circumference, only this latter combination remained at a significantly higher risk, although the effect estimate was attenuated by 43% and 48%, respectively. In sum, a high TV viewing time may be a risk factor for COVID-19 mortality even amongst highly active individuals. Higher adiposity appears to partly explain the elevated risk associated with a low physical activity level and a high TV viewing time.

Television Viewing Time, Overweight, Obesity, and Severe COVID-19: A Brief Report From UK Biobank.

BACKGROUND: Overweight and obesity are well-established risk factors for COVID-19 severity; however, less is known about the role of sedentary behaviors such as television (TV) viewing. The purpose of this brief report was to determine whether lower TV viewing time may mitigate the risk of severe COVID-19 in individuals with excess weight. METHODS: We analyzed 329,751 UK Biobank participants to investigate the independent and combined associations of BMI and self-reported TV viewing time with odds of severe COVID-19 (inpatient COVID-19 or COVID-19 death). RESULTS: Between March 16 and December 8, 2020, there were 1648 instances of severe COVID-19. Per 1-unit (hours per day) increase in TV viewing time, the odds of severe COVID-19 increased by 5% (adjusted odds ratio = 1.05, 95% confidence interval = 1.02-1.08). Compared with normal-weight individuals with low (≤1 h/d) TV viewing time, the odds ratios for overweight individuals with low and high (≥4 h/d) TV viewing time were 1.17 (0.89-1.55) and 1.66 (1.31-2.11), respectively. For individuals with obesity, the respective ORs for low and high TV viewing time were 2.18 (1.61-2.95) and 2.14 (1.69-2.73). CONCLUSION: Higher TV viewing time was associated with higher odds of severe COVID-19 independent of BMI and moderate to vigorous physical activity. Additionally, low TV viewing time may partly attenuate the elevated odds associated with overweight, but not obesity.

Device-assessed sleep and physical activity in individuals recovering from a hospital admission for COVID-19: a multicentre study.

BACKGROUND: The number of individuals recovering from severe COVID-19 is increasing rapidly. However, little is known about physical behaviours that make up the 24-h cycle within these individuals. This study aimed to describe physical behaviours following hospital admission for COVID-19 at eight months post-discharge including associations with acute illness severity and ongoing symptoms. METHODS: One thousand seventy-seven patients with COVID-19 discharged from hospital between March and November 2020 were recruited. Using a 14-day wear protocol, wrist-worn accelerometers were sent to participants after a five-month follow-up assessment. Acute illness severity was assessed by the WHO clinical progression scale, and the severity of ongoing symptoms was assessed using four previously reported data-driven clinical recovery clusters. Two existing control populations of office workers and individuals with type 2 diabetes were comparators. RESULTS: Valid accelerometer data from 253 women and 462 men were included. Women engaged in a mean ± SD of 14.9 ± 14.7 min/day of moderate-to-vigorous physical activity (MVPA), with 12.1 ± 1.7 h/day spent inactive and 7.2 ± 1.1 h/day asleep. The values for men were 21.0 ± 22.3 and 12.6 ± 1.7 h /day and 6.9 ± 1.1 h/day, respectively. Over 60% of women and men did not have any days containing a 30-min bout of MVPA. Variability in sleep timing was approximately 2 h in men and women. More severe acute illness was associated with lower total activity and MVPA in recovery. The very severe recovery cluster was associated with fewer days/week containing continuous bouts of MVPA, longer total sleep time, and higher variability in sleep timing. Patients post-hospitalisation with COVID-19 had lower levels of physical activity, greater sleep variability, and lower sleep efficiency than a similarly aged cohort of office workers or those with type 2 diabetes. CONCLUSIONS: Those recovering from a hospital admission for COVID-19 have low levels of physical activity and disrupted patterns of sleep several months after discharge. Our comparative cohorts indicate that the long-term impact of COVID-19 on physical behaviours is significant.

Sedentary behaviour, physical activity and psychobiological stress reactivity: A systematic review.

BACKGROUND: Sedentary behaviour, physical activity, and psychobiological reactivity to acute psychological stress are independent risk factors for cardiovascular disease. Sedentary behaviour and physical activity influence autonomic, haemodynamic, and inflammatory pathways under resting conditions, and these pathways become activated under acute psychological stress. However, it is unclear whether sedentary behaviour and physical activity relate to psychobiological responses to stress. Thus, the aim of this study is to systematically review sedentary behaviour and physical activity in the context of psychobiological reactivity to acute psychological stress. METHODS: Sedentary behaviour, physical activity and psychobiological stress reactivity search terms were combined, and several databases were searched in duplicate. Eligibility criteria included: (1) a validated measure of sedentary behaviour/physical activity; (2) cardiovascular, inflammatory, neuroendocrine, or respiratory markers measured at rest and in response to laboratory-induced acute psychological stress. RESULTS: 6084 articles were screened, with 11 included in a narrative synthesis. No studies measured postural components of sedentary behaviour, but 2/4 studies found that markers of sedentary behaviour (e.g., physical inactivity) were associated with elevated heart rate, dysregulated heart rate variability, or lowered cortisol responses to stress. Higher volumes of physical activity were linked to lower HR, cortisol, or immune responses to stress in 4/7 studies. CONCLUSIONS: Extensive methodological variability precludes conclusions from being drawn. This review should be used to guide a more homogeneous and gold-standard literature, which accounts for postural components of sedentary behaviour using inclinometery, and the whole physical activity intensity spectrum using universal and reproducible approaches.

Feasibility and acceptability of high-intensity interval training and moderate-intensity continuous training in kidney transplant recipients: the PACE-KD study.

BACKGROUND: Kidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs. METHODS: Twenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m2; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80-90% watts at V̇O2peak), HIITB (4×4 min intervals; 80-90% V̇O2peak) or MICT (~40 min; 50-60% V̇O2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence. RESULTS: Twenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O2peak (mL/kg-1/min-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported. CONCLUSIONS: This is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention. TRIAL REGISTRATION: ISRCTN, ISRCTN17122775 . Registered on 30 January 2017.

Sedentary behaviour is associated with heightened cardiovascular, inflammatory and cortisol reactivity to acute psychological stress.

BACKGROUND: Sedentary behaviour is a risk factor for cardiovascular disease (CVD), but the underlying mechanisms remain unclear. Exaggerated psychobiological responses to acute psychological stress increase CVD risk. Sedentary behaviour is associated with characteristics that can predict large psychobiological stress response patterns (e.g., elevated resting blood pressure and systemic inflammation), but it is currently unknown whether sedentary behaviour and stress reactivity are directly linked. The aim of this study was to examine associations between device-assessed sedentary behaviour and measures of stress reactivity. METHODS: Sixty-one healthy adults wore an activPAL (thigh) and ActiGraph (wrist) for seven days to measure habitual levels of sedentary behaviour (mean ± SD = 9.96 ± 1.48 h/day) and moderate-to-vigorous physical activity (mean ± SD = 101.82 ± 42.92 min/day). Participants then underwent stress reactivity testing, where beat-to-beat cardiovascular (e.g., blood pressure, total peripheral resistance), inflammatory (plasma interleukin-6, leukocytes) and salivary cortisol measurements were taken in response to an 8-minute socially evaluative Paced Auditory Serial Addition Test. RESULTS: Higher volumes of daily sedentary behaviour were associated with larger stress responses for diastolic blood pressure (Β=1.264, 95%CI=0.537-1.990, p = .005), total peripheral resistance (Β=40.563, 95%CI=19.310-61.812, p < .001), interleukin-6 (Β=0.219, 95%CI=0.109-0.329, p < .001) and cortisol (Β=1.844, 95%CI=1.139-2.549, p < .001). These findings emerged independent of a priori determined covariates, including daily levels of moderate-to-vigorous physical activity and adiposity. DISCUSSION: Exaggerated stress reactivity is characteristic of high sedentary behaviour and could be a novel mechanism linking sedentary behaviour with CVD. Future work should examine the impact of reducing sedentary behaviour on measures of stress reactivity, as this may have clinical relevance for preventing CVD.

Effect of high intensity interval training and moderate intensity continuous training on lymphoid, myeloid and inflammatory cells in kidney transplant recipients.

Kidney transplantations are seen to be a double-edge sword. Transplantations help to partially restore renal function, however there are a number of health-related co-morbidities associated with transplantation. Cardiovascular disease (CVD), malignancy and infections all limit patient and graft survival. Immunosuppressive medications alter innate and adaptive immunity and can result in immune dysfunction. Over suppression of the immune system can result in infections whereas under suppression can result in graft rejection. Exercise is a known therapeutic intervention with many physiological benefits. Its effects on immune function are not well characterised and may include both positive and negative influences depending on the type, intensity, and duration of the exercise bout. High intensity interval training (HIIT) has become more popular due to it resulting in improvements to tradional and inflammatory markers of cardiovascular (CV) risk in clinical and non-clinical populations. Though these improvements are similar to those seen with moderate intensity exercise, HIIT requires a shorter overall time commitment, whilst improvements can also be seen even with a reduced exercise volume. The purpose of this study was to explore the physiolocial and immunological impact of 8-weeks of HIIT and moderate intensity continuous training (MICT) in kidney transplan recipients (KTRs). In addition, the natural variations of immune and inflammatory cells in KTRs and non-CKD controls over a longitudinal period are explored. Newly developed multi-colour flow cytometry methods were devised to identify and characterise immune cell populations. Twenty-six KTRs were randomised into one of two HIIT protocols or MICT: HIIT A (n=8; 4-, 2-, and 1-min intervals; 80-90% VO2peak), HIIT B (n=8, 4x4 min intervals; 80-90% VO2peak), or MICT (n=8, ~40 min; 50-60% VO2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 ± 2 weeks). Blood samples taken pre-training, mid training, post-training and 3 months later. Novel multi-colour flow cytometric panels were developed to characterise lymphoid and myeloid cell population from peripheral blood mononuclear cells. No changes were observed for circulating immune and inflammatory cells over the 8-week interventions. The feasibility study does not suggest that exercise programmes using HIIT and MICT protocols elicit adverse negative effects on immunity in KTRs. Therefore, such protocols may be immunologically safe for these patients. The inability of the participants to achieve the target exercise intensities may be due to physiological abnormalities in this population which warrants further investigation.