We examined the validity and reliability of the Apple Watch heart rate sensor during and in recovery from exercise. Twenty-one males completed treadmill exercise while wearing two Apple Watches (left and right wrists) and a Polar S810i monitor (criterion). Exercise involved 5-min bouts of walking, jogging, and running at speeds of 4 km.h −1 , 7 km.h −1 , and 10 km.h −1 , followed by 11 min of rest between bouts. At all exercise intensities the mean bias was trivial. There were very good correlations with the criterion during walking (L: r=0.97; R: r=0.97), but good (L: r=0.93; R: r=0.92) and poor/good (L: r=0.81; R: r=0.86) correlations during jogging and running. Standardised typical error of the estimate was small, moderate, and moderate to large. There were good correlations following walking, but poor correlations following jogging and running. The percentage of heart rates recorded reduced with increasing intensity but increased over time. Intra-device standardised typical errors decreased with intensity. Inter-device standardised typical errors were small to moderate with very good to nearly perfect intraclass correlations. The Apple Watch heart rate sensor has very good validity during walking but validity decreases with increasing intensity.

Background In recent years, criticism of the percentage range approach for individualised exercise prescription has intensified and we were concerned that sub-optimal exercise dose (especially intensity) may be in part responsible for the variability in the effectiveness of cardiac rehabilitation (CR) programmes in the United Kingdom (UK). The aim was to investigate the fidelity of a structured Phase III CR programme, by monitoring and quantifying exercise training intensity. Design Observational study. Methods The programme comprised 16 sessions over 8 weeks, where patients undertook an interval, circuit training approach within national guidelines for exercise prescription (40–70% heart rate reserve [HRR]). All patients wore an Apple Watch (Series 0 or 2, Watch OS2.0.1, Apple Inc., California, USA). We compared the mean % heart rate reserve (%HRR) achieved during the cardiovascular training component (%HRR-CV) of a circuit-based programme, with the %HRR during the active recovery phases (%HRR-AR) in a randomly selected cohort of patients attending standard CR. We then compared the mean %HRR-CV achieved with the minimal exercise intensity threshold during supervised exercise (40% HRR) recommended by national governing bodies. Results Thirty cardiac patients (83% male; mean age [SD] 67 [ 10 ] years; BMI 28.3 [4.6] kg∙m -2 ) were recruited. We captured 332 individual training sessions. The mean %HRR-CV and %HRR-AR were 37 (10) %, and 31 (13) %, respectively. There was weak evidence to support the alternative hypothesis of a difference between the %HRR-CV and 40% HRR. There was very strong evidence to accept the alternative hypothesis that the mean %HRR-AR was lower than the mean %HRR-CV, median standardised effect size 1.1 (95%CI: 0.563 to 1.669), with a moderate to large effect. Conclusion Mean exercise training intensity was below the lower limit of the minimal training intensity guidelines for a Phase III CR programme. These findings may be in part responsible for previous reports highlighting the significant variability in effectiveness of UK CR services and poor CRF improvements observed from several prior investigations.

Background Recent concerns have cast doubt over the effectiveness of cardiac rehabilitation [CR] programmes for improving cardiorespiratory fitness [CRF] in patients with a history of cardiac disease in the United Kingdom [UK]. We aimed to characterise the weekly progression of exercise training dose over an 8-week Phase III CR programme as we felt this may be partly responsible for the lack of improvement in CRF reported in previous studies. Design Observational study. Methods We evaluated a community-based Phase III CR programme in the UK. During each training session, patients wore an Apple Watch and the weekly progression of exercise training dose/load was quantified. The analysis was based on 332 individual training sessions. Exercise intensity [% heart rate reserve] during the cardiovascular [CV] exercise training component [%HRR-CV], CV training duration; estimated changes in cardiorespiratory fitness [change in estimated metabolic equivalents (METs)]; session rating of perceived exertion [sRPE], sRPE training load [sRPE-TL], and exercise training impulse [TRIMP] were evaluated. Results Thirty cardiac patients [83% male; age [SD] 67.0 [10.0] years; body mass index [SD] 28.3 [4.6] kg�m-2 ] were recruited to an 8-week programme [16 sessions in total]. Bayesian repeated-measures ANOVA indicated anecdotal evidence for the alternative hypothesis for changes in %HRR-CV (BF 10 = 0.61), sRPE (BF 10 = 1.1), and change in estimated METs (BF 10 = 1.2) during CR. Conversely, Bayesian repeated-measures ANOVA showed

Background:The core of cardiac rehabilitation (CR) is structured exercise training. CR reduces 28-56% hospital readmission rate, and around 25% increases cardiorespiratory fitness but the number of outpatients CR centers in Saudi Arabia (SA) is very limited and there is a need to establish outpatient CR (Phase III) in SA. Furthermore, the awareness of outpatient CR in SA is unknown. Aim: To determine the main barriers to establishing an outpatient CR program (Phase III) in the western region of SA, as well as assess the awareness of outpatient CR (Phase III) in the western region of SA. Methods: A cross-sectional study survey was conducted between March -July 2021 among physiotherapists, cardiologists and the cardiac surgeon using a questionnaire distributed electronically to determine the awareness level of outpatient CR and barriers to establishing outpatient CR (Phase III) in the western region of SA. Frequencies and percentages were used to report the variables. Results: Of the 141 participants who completed the online survey, our findings showed that 131 (93%) were aware of CR but only 29 (21%) were aware of the four phases of CR. There were three main barriers to establishing CR: lack of appropriate CR 135 (96%); lack of awareness among healthcare professions of CR and its benefits 134 (95%) and the lack of healthcare providers trained in CR 133 (94%). There was a significant relationship between physiotherapists and cardiologists' responses on agreeing to all barriers to establishing CR in SA (r=0.69, P =0.03). Conclusion:To overcome the barriers to establishing CR outpatient centers in the western region of SA, it is recommended to provide more CR outpatient training programs to healthcare providers and raise the awareness of the CR phases, its benefits, and the risk factors for developing cardiac diseases among healthcare providers.

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