Background An increasing number of wrist-worn wearables are being examined in the context of health care. However, studies of their use during physical education (PE) lessons remain scarce. Objective We aim to examine the reliability and validity of the Fizzo Smart Bracelet (Fizzo) in measuring heart rate (HR) in the laboratory and during PE lessons. Methods In Study 1, 11 healthy subjects (median age 22.0 years, IQR 3.75 years) twice completed a test that involved running on a treadmill at 6 km/h for 12 minutes and 12 km/h for 5 minutes. During the test, participants wore two Fizzo devices, one each on their left and right wrists, to measure their HR. At the same time, the Polar Team2 Pro (Polar), which is worn on the chest, was used as the standard. In Study 2, we went to 10 schools and measured the HR of 24 students (median age 14.0 years, IQR 2.0 years) during PE lessons. During the PE lessons, each student wore a Polar device on their chest and a Fizzo on their right wrist to measure HR data. At the end of the PE lessons, the students and their teachers completed a questionnaire where they assessed the feasibility of Fizzo. The measurements taken by the left wrist Fizzo and the right wrist Fizzo were compared to estimate reliability, while the Fizzo measurements were compared to the Polar measurements to estimate validity. To measure reliability, intraclass correlation coefficients (ICC), mean difference (MD), standard error of measurement (SEM), and mean absolute percentage errors (MAPE) were used. To measure validity, ICC, limits of agreement (LOA), and MAPE were calculated and Bland-Altman plots were constructed. Percentage values were used to estimate the feasibility of Fizzo. Results The Fizzo showed excellent reliability and validity in the laboratory and moderate validity in a PE lesson setting. In Study 1, reliability was excellent (ICC>0.97; MD<0.7; SEM<0.56; MAPE<1.45%). The validity as determined by comparing the left wrist Fizzo and right wrist Fizzo was excellent (ICC>0.98; MAPE<1.85%). Bland-Altman plots showed a strong correlation between left wrist Fizzo measurements (bias=0.48, LOA=–3.94 to 4.89 beats per minute) and right wrist Fizzo measurements (bias=0.56, LOA=–4.60 to 5.72 beats per minute). In Study 2, the validity of the Fizzo was lower compared to that found in Study 1 but still moderate (ICC>0.70; MAPE<9.0%). The Fizzo showed broader LOA in the Bland-Altman plots during the PE lessons (bias=–2.60, LOA=–38.89 to 33.69 beats per minute). Most participants considered the Fizzo very comfortable and easy to put on. All teachers thought the Fizzo was helpful. Conclusions When participants ran on a treadmill in the laboratory, both left and right wrist Fizzo measurements were accurate. The validity of the Fizzo was lower in PE lessons but still reached a moderate level. The Fizzo is feasible for use during PE lessons.

BackgroundSufficient physical activity (PA) and limited screen time (ST) have been shown to be positively associated with a variety of mental health outcomes. It has been known that PA and ST are independently associated with life satisfaction. Whereas, little is known about the association between combinations of PA and ST with life satisfaction in adults. This study aimed to explore the associations between PA and ST (in insolation or combination) and life satisfaction in adults.MethodsData from the 2014 European Social Survey (ESS) round 7 consisting of 22 countries were analyzed in this study. In total, self-reported data from 40,185 adults were included in the final analysis. The self-administered method was used to collect demographic information, PA, ST, and life satisfaction. The prevalence of meeting PA guidelines (at least 150 min per week) and ST guidelines (no more than 3 h per day) was calculated according to Canadian 24-h Movement Guidelines for Adults.ResultsAdults who were engaged in sufficient PA and limited ST were more likely to report a higher level of life satisfaction. Meeting PA or ST guidelines was more likely to report higher life satisfaction scores [odds ratio (OR) = 1.31, 95% CI: 1.16–1.47]. Compared with not meeting any guidelines, those who met both PA and ST guidelines had a higher OR (OR = 1.55, 95% CI: 1.37–1.76).ConclusionThis study found that participating PA while limiting ST concurrently was linked with better life satisfaction. Creating an active lifestyle is important to population’s well-being.

BACKGROUND More and more wrist-worn trackers are examined in health care. However, feasibility, reliability and validity studies for Physical Education (PE) classes remain scarce. OBJECTIVE This article was to examine the reliability and validity of Fizzo Smart Bracelet (FSB)in measuring heart rate (HR) in laboratory and examine the validity and feasibility in PE classes. METHODS In Study 1, 11 healthy subjects (5 males 23.8 ± 1.8 years, 6 females 21.0 ± 1.3 years) completed the test which included running on the treadmill at the speed of 6 km/h and 12 km/h for 12min and 5min respectively for two times. During the test, participants wore two FSBs on their left and right wrists to measure the HR data, resembling a watch. At the same time, the Polar Team2 Pro (Polar) was worn on the chest as the gold standard on their chest. In Study 2, we went to 10 schools and measured 24 students (11 males 14.0 ± 1.4 years, 13 females 13.9 ± 1.1 years) in PE classes. During the PE classes each student worn a Polar on chest and an FSB on the right wrist to measure HR data. At the end of the PE classes, the students and their teachers finished the questionnaire for assessment the feasibility of FSB. To measure reliability, intraclass correlations (ICC), mean difference (MD), standard error of measurement (SEM), mean absolute percentage errors (MAPE) were used. To measure validity, intraclass correlations (ICC), limits of agreement (LOA), mean absolute percentage errors (MAPE) were calculated. Bland-Altman plots were constructed. Percentage value were used to estimate the feasibility of FSB. RESULTS In Study 1 the FSB showed high reliability between the Left Fizzo (LF) and Right Fizzo (RF) (ICC > 0.97, MD < 0.7, SEM < 0.56 and MAPE < 1.45%). The validity of LF and RF were high (ICC > 0.98, MAPE < 1.85%). Bland-Altman plots showed strong correlation. LF (bias: 0.48, LOA: -3.94 ~ 4.89 bpm) and RF (bias: 0.56, LOA: -4.60 ~ 5.72 bpm). Compared to study 1, the validity of FSB was lower in Study 2, but still moderate (ICC > 0.70, MAPE < 9.0%), and the FSB showed broad LOA in the Bland-Altman plots (bias: -2.60, LOA: -38.89 ~ 33.69bpm). FSB slightly underestimate the HR compared with Polar. Most participants considered the FSB is very comfortable and easy to apply and remove. All the teachers thought FSB is helpful. CONCLUSIONS Running on the treadmill in the laboratory, both LF and RF were all accurate. Compare to the laboratory, the validity of FSB was decreased in PE classes but still reached moderate level. FSB is comfortable to wear, easy to apply and remove, it has high application value in PE class setting.