The safety of isometric exercise: rethinking the exercise prescription paradigm for those with stage 1 hypertension.

Few studies have investigated the relative safety of prescribing isometric exercise (IE) to reduce resting blood pressure (BP). This study aimed to ascertain the safety of the hemodynamic response during an IE wall squat protocol.Twenty-six hypertensive (BP of 120-139 mm Hg systolic and/or 80-90 mm Hg diastolic) males (45 ± 8 years; 1.78 ± 0.07 m; 89.7 ± 12.3 kg; mean ± SD), visited the laboratory on 2 separate occasions. Heart rate (HR) and BP were measured at rest and continuously throughout exercise. In visit 1, participants completed a continuous incremental isometric wall squat exercise test, starting at 135° of knee flexion, decreasing by 10° every 2 minutes until 95° (final stage). Exercise was terminated upon completion of the test or volitional fatigue. The relationship between knee joint angle and mean HR was used to calculate the participant-specific knee joint angle required to elicit a target HR of 95% HRpeak. This angle was used to determine exercise intensity for a wall squat training session consisting of 4 × 2 minute bouts (visit 2).Systolic BPs during the exercise test and training were 173 ± 21 mm Hg and 171 ± 19 mm Hg, respectively, (P > .05) and were positively related (r = 0.73, P  .05) and were positively related (r = 0.42, P  250 mm Hg. Diastolic BP values > 115 mm Hg were recorded in 12 participants during the incremental test and 6 participants during the training session. Peak rate pressure product was 20681 ± 3911 mm Hg bpm during the IE test and was lower (18074 ± 3209 mm Hg bpm) during the IE session (P = .002). No adverse effects were reported.Based on the current ACSM guidelines for aerobic exercise termination, systolic BP does not reach the upper limit during IE in this population. Diastolic BP exceeds 115 mm Hg in some during the IE protocol, which may suggest the need to individualise IE training prescription in some with suboptimal BP control. Future research is required to ascertain if IE requires modified BP termination guidelines

Multiproxy records of climate variability for Kamchatka for the past 400 years

International audienceTree rings, ice cores and glacial geologic histories for the past several centuries offer an opportunity to characterize climate variability and to identify the key climate parameters forcing glacier expansions. A newly developed larch ring-width chronology is presented for Kamchatka that is sensitive to past summer temperature variability. This record provides the basis to compare with other proxy records of inferred temperature and precipitation change from ice core and glacier records, and to characterize climate for the region over the past 400 years. Individual low growth years in the larch record are associated with several known and proposed volcanic events that have been observed in other proxy records from the Northern Hemisphere. Comparison of the tree-rings with an ice core record of melt feature index for Kamchatka's Ushkovsky volcano confirms a 1?3 year dating accuracy for this ice core series over the late 18th to 20th centuries. Decadal variations of low summer temperatures (tree-ring record) and high annual precipitation (ice core record) are broadly consistent with intervals of positive mass balance measured and estimated at several glaciers, and with moraine building, provides a basis to interpret geologic glacier records

Neurohumoral and ambulatory haemodynamic adaptations following isometric exercise training in unmedicated hypertensive patients

Objective: Hypertension remains the leading modifiable risk factor for cardiovascular disease (CVD). Isometric exercise training (IET) has been shown to be a useful non-pharmacological intervention for reducing resting blood pressure (BP). This study aimed to measure alterations in office BP, ambulatory BP, cardiac autonomic modulation and inflammatory and vascular biomarkers following a programme of IET in unmedicated hypertensive patients. Methods: Twenty-four unmedicated stage 1 hypertensive patients (age 43.8±7.3 years; height, 178.1±7 cm; weight 89.7±12.8 kg) were randomly assigned in a cross-over study design, to 4-weeks of home based IET and control period, separated by a 3-week washout period. Office and Ambulatory BP, cardiac autonomic modulation, and inflammatory and vascular biomarkers were recorded pre and post IET and control periods. Results: Clinic and 24-hour ambulatory BP significantly reduced following IET by 12.4/6.2 mmHg and 11.8/5.6 mmHg in systolic/diastolic BP, respectively (p<0.001 for both), compared to the control. The BP adaptations were associated with a significant (p=0.018) reduction in the average real variability of 24-hour ambulatory BP following IET, compared to control. Cardiac autonomic modulation improved by 11% (p<0.001), baroreceptor reflex sensitivity improved by 47% (p<0.001), and interleukin-6 and asymmetric dimethylarginine reduced by 10% (p=0.022) and 19% (p=0.023), respectively, which differed significantly to the control period. Conclusion: This is the first evidence of durable BP reduction and wider CVD risk benefits of IET in a relevant patient population. Our findings support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of HTN

Left Ventricular Function and Cardiac Biomarker Release-The Influence of Exercise Intensity, Duration and Mode: A Systematic Review and Meta-Analysis.

OBJECTIVE: We performed a systematic review, meta-analysis and meta-regression of exercise studies that sought to determine the relationship between cardiac troponin (cTn) and left ventricular (LV) function. The second objective was to determine how study-level and exercise factors influenced the variation in the body of literature. DATA SOURCES: A systematic search of Pubmed Central, Science Direct, SPORTDISCUS and MEDLINE databases. ELIGIBILITY CRITERIA: Original research articles published between 1997 and 2018 involving > 30 mins of continuous exercise, measuring cardiac troponin event rates and either LV ejection fraction (LVEF) or the ratio of the peak early (E) to peak late (A) filling velocity (E/A ratio). DESIGN: Random-effects meta-analyses and meta-regressions with four a priori determined covariates (age, exercise heart rate [HR], duration, mass). REGISTRATION: The systematic search strategy was registered on the PROSPERO database (CRD42018102176). RESULTS: Pooled cTn event rates were evident in 45.6% of participants (95% confidence interval (CI) 33.6-58.2); however, the overall effect was non-significant (P > 0.05). There were significant (P < 0.05) reductions in E/A ratio of - 0.38 (SMD = - 1.2, 95% CI - 1.4 to - 1.0), and LVEF of - 2.02% (SMD = - 0.38, 95% CI - 0.7 to - 0.1) pre- to post-exercise. Increased exercise HR was a significant predictor of troponin release and E/A ratio. Participant age was negatively associated with cTn release. There was a significant negative association between E/A ratio with increased rates of cTn release (P < 0.05). CONCLUSIONS: High levels of statistical heterogeneity and methodological variability exist in the majority of EICF studies. Our findings show that exercise intensity and age are the most powerful determinants of cTn release. Diastolic function is influenced by exercise HR and cTn release, which implies that exercise bouts at high intensities are enough to elicit cTn release and reduce LV diastolic function. Future EICF studies should (1) utilise specific echocardiographic techniques such as myocardial speckle tracking, (2) ensure participants are euhydrated during post-exercise measurements, and (3) repeat measures in the hours following exercise to assess symptom progression or recovery. It is also recommended to further explore the relationship between aging, training history, and exercise intensity on cTn release and functional changes

Cardiac autonomic and left ventricular mechanics following high intensity interval training: a randomised cross-over controlled study.

Physical inactivity and sedentary behaviour is associated with increased cardiovascular disease risk. Short duration high intensity interval training (HIIT) has been shown to improve important health parameters. The aim of the present study was to assess the combined adaptations of the cardiac autonomic nervous system and myocardial functional and mechanical parameters to HIIT. Forty physically inactive and highly sedentary males completed 2-weeks of HIIT and control period. The HIIT protocol consisted of 3x30-second maximal cycle ergometer sprints against a resistance of 7.5% body weight, interspersed with 2-minutes of active recovery. Total power spectral density (PSD) and associated low-frequency (LF) and high-frequency (HF) power spectral components of heart rate variability were recorded. Conventional and speckle tracking echocardiography recorded left ventricular (LV) structural, functional and mechanical parameters. HIIT produced a significant increase in total ln PSD and ln HF, and significant decrease in LF/HF ratio (all p<0.05) compared to the control period. HIIT produced significant improvements in LV diastolic function, including lateral E’, estimated filling pressure (E/E’ ratio), E deceleration time, and isovolumetric relaxation time (p<0.05 for all). Fractional shortening was the only conventional marker of LV systolic function to significantly improve (p<0.05). In this setting, there were significant improvements in global peak systolic strain rate, early and late diastolic strain rate and early to late diastolic strain rate ratio, as well as apical rotation, apical systolic and diastolic rotation velocity, apical radial and circumferential strain and strain rate, LV torsion and LV systolic and diastolic torsion velocity (all p<0.05). A short-term programme of HIIT was associated with a significant increase in cardiac autonomic modulation, demonstrated by a residual increase in cardiac vagal activity as well as significantly improved cardiac function and mechanics. This study demonstrates that HIIT may be an important stimulus to reduce the health implications associated with physical inactivity and sedentary behaviour

One year of isometric exercise training for blood pressure management in men: a prospective randomized controlled study

Objective: Isometric exercise training (IET) over 4-12 weeks is an effective antihypertensive intervention. However, blood pressure (BP) reductions are reversible if exercise is not maintained. No work to date has investigated the long-term effects of IET on resting BP. Methods: We randomized 24 unmedicated patients with high-normal BP to a 1-year wall squat IET intervention or nonintervention control group. Resting BP and various clinically important haemodynamic variables, including heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were measured pre and post the 1-year study period. Results: One year of IET produced statistically significant reductions in resting systolic (-8.5 ± 5 mmHg, P < 0.001) and diastolic (-7.3 ± 5.8 mmHg, P < 0.001) BP compared with the control group. There was also a significant reduction in resting HR (-4.2 ± 3.7 b/min, P = 0.009) and a significant increase in SV (11.2 ± 2.8 ml, P = 0.012), with no significant change in CO (0.12 ± 2.8 l/min, P = 0.7). TPR significantly decreased following IET (-246 ± 88 dyne·s/cm5, P = 0.011). Adherence to the IET sessions was 77% across all participants (3x IET sessions per week), with no participant withdrawals. Conclusion: This novel study supports IET as an effective long-term strategy for the management of resting BP, producing clinically important, chronic BP adaptations in patients at risk of hypertension. Importantly, this work also demonstrates impressive long-term adherence rates, further supporting the implementation of IET as a means of effective BP management in clinical populations

Design Considerations for the Integrated Delivery of Cognitive Behavioral Therapy for Depression: A User-Centered Design Study

Background: Adherence to computerized cognitive behavioral therapy (cCBT) programs in real-world settings can be poor, and in the absence of therapist support, effects are modest and short term. Moreover, because cCBT systems tend toward limited support and thus low-intensity treatment, they are typically most appropriate for people experiencing mild to moderate mental health difficulties. Blended therapy, that is, combining direct therapist contact with cCBT or psychoeducational materials, has been identified as one possible approach to address these limitations and widen access to individual CBT for depression. Building on the initial success of blended therapy, we explore an integrated approach that seeks to seamlessly combine face-to-face contact, electronic contact, and between-session activities. Integration also considers how the technology can support therapists’ workflow and integrate with broader health care systems. The ultimate aim is to provide a structure within which therapists can deliver high-intensity treatments, while also greatly reducing face-to-face contact. Objective: The research aimed to explore patients’ and therapists’ views on using a system for the delivery of individual treatment for depression that integrates face-to-face therapist contact with access to online resources and with synchronous online therapy sessions that allow collaborative exercises, and to establish design requirements and thus key design considerations for integrated systems that more seamlessly combine different modes of communication. Methods: We conducted a series of four user-centered design studies. This included four design workshops and seven prototype testing sessions with 18 people who had received CBT for depression in the past, and 11 qualitative interviews and three role-play sessions with 12 CBT therapists experienced in the treatment of depression. Studies took place between July and December 2017 in Bristol, United Kingdom. Results: Workshops and prototyping sessions with people who had received CBT identified three important requirements for integrated platforms delivering CBT therapy for depression as follows: (1) features that help to overcome depression-related barriers, (2) features that support engagement, and (3) features that reinforce learning and support the development of new skills. Research with therapists highlighted the importance of the therapist and client working together, the impact of technology on therapists’ workflow and workload, challenges and opportunities related to the use of online resources, and the potential of technology to support patient engagement. We use these findings to inform 12 design considerations for developing integrated therapy systems. Conclusions: To meet clients’ and therapists’ needs, integrated systems need to help retain the personal connection, support both therapist- and patient-led activities, and provide access to materials and the ability to monitor progress. However, developers of such systems should be mindful of their capacity to disrupt current work practices and increase therapists’ workload. Future research should evaluate the impact of integrated systems on patients and therapists in a real-world context

Integrating the Digital and the Traditional to Deliver Therapy for Depression: Lessons from a Pragmatic Study

Traditional approaches to psychotherapy emphasise face-to-face contact between patients and therapists. In contrast, current computerised approaches tend to minimise this contact. This can limit the range of mental health difficulties for which computerised approaches are effective. Here, we explore an alternative approach that integrates face-to-face contact, electronic contact, online collaboration, and support for between-session activities. Our discussion is grounded in the design of a platform to deliver psychotherapy for depression. We report findings of an 11-month pragmatic study in which 17 patients received treatment for depression via the platform. Results show how design decisions had a significant impact on the dynamics of therapeutic sessions and the establishment of patient-therapist relationships. For example, the use of instant messaging for synchronous, in-session contact slowed communication, but also provided a valuable space for reflection and helped to maintain session focus. We discuss the impact of flexibility and the potential of integrated approaches to both enhance and reduce patient engagement

Myocardial work and left ventricular mechanical adaptations following isometric exercise training in hypertensive patients

Purpose Hypertension is a major risk factor for cardiovascular disease. Isometric exercise training (IET) reduces resting and ambulatory blood pressure; however, few studies have investigated the myocardial adaptations following IET. Methods We randomly assigned 24 unmedicated hypertensive patients in a cross-over study design to 4-weeks of IET and control period, separated by a 3-week washout period. Speckle tracking echocardiography was used to measure left ventricular (LV) mechanics, and global myocardial work indices were derived from non-invasive LV pressure-strain loops constructed from global longitudinal strain (GLS) indexed to brachial systolic blood pressure. Results IET significantly improved GLS (− 2.3 ± 2%, p < 0.001) and global work efficiency (2.8 ± 2%, p < 0.001), and significantly reduced global wasted work (− 42.5 ± 30 mmHg%, p < 0.001) with no significant change during the control period. Conclusions This is the first evidence to demonstrate that IET significantly improved cardiac health in a relevant patient population. Our findings have important clinical implications for patients with high blood pressure and support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of hypertension