Table 4.
Study methods and objectives.
| Methods and objectives | Studies (N=53), n (%) | |||
| Number of wearables per study | ||||
|
|
1 | 37 (74) | ||
|
|
2 | 12 (23) | ||
|
|
≥3 | 2 (4) | ||
| Wearable company (models)a | ||||
|
|
Polar Electro (RCX3, H7, RS800XC, FT1, FT7, Team 2 [Pro], RS800, RS400, WearLink, Accurex Plus, A300, and M400) | 16 (30) | ||
|
|
Maxim Integrated (iButton Hygrochron and Thermochron) | 13 (25) | ||
|
|
Fitbit (Ionic, Charge 2, and Flex) | 5 (9) | ||
|
|
Medtronic (Zephyr BioHarness) | 4 (8) | ||
|
|
Philips Respironics (Actical and Actiwatch 2), Onset Corp (HOBO Pendant), and Empatica (E4) | 3 (6; each) | ||
|
|
Crossbridge Scientific (KuduSmart), Actigraph (GT3X and GT3X+), Intel (Basis Peak Watch), BodyMedia (SenseWear Pro 3), Sony (SmartBand Talk SWR30 and SWR12) | 2 (4; each) | ||
|
|
Omron Healthcare (HJ-720 ITC pedometer), STATSports (Viper Pod), Microsoft (Band), Garmin (Vivoactive HR), Aipermon (APM), Stayhealthy (RT3), GISupply (LW-360HR), Lifensense (Mambo 2), LASCAR (EL-USB-2-LCD+), Easylog (Easylog), PAL Technologies (activPAL and activPAL3C) | 1 (2; each) | ||
| Measured parameter with wearablea | ||||
|
|
Heart rate | 30 (57) | ||
|
|
Physical activity | 15 (28) | ||
|
|
Energy expenditure | 8 (15) | ||
|
|
Skin temperature | 12 (23) | ||
|
|
Electrodermal activity | 5 (9) | ||
|
|
Sleep (onset, offset duration, and efficiency) | 7 (13) | ||
|
|
Individually experienced temperature | 14 (26) | ||
|
|
Others (local sweat rate, respiratory rate, and GPS location) | 7 (13) | ||
| Wear location of wearablea | ||||
|
|
Wristband | 25 (47) | ||
|
|
Chest strap | 18 (34) | ||
|
|
Attached to clothing or accessories | 15 (28) | ||
|
|
Taped to the skin | 5 (9) | ||
|
|
Other: shirt, back strap, around upper arm, or not specified | 8 (15) | ||
| Climate change–related extreme weather | ||||
|
|
Heat | 52 (98) | ||
|
|
Wildfire | 1 (2) | ||
| Measured environmental conditiona | ||||
|
|
Temperature | 50 (94) | ||
|
|
Relative humidity | 40 (75) | ||
|
|
Precipitation | 7 (13) | ||
|
|
Other (wind speed, wet bulb temperature, dry bulb temperature, dew point, mean radiant temperature, barometric pressure, visibility, CO2 concentration, and air quality) | 22 (42) | ||
| Measurement location or data source for environmental conditiona | ||||
|
|
Nearest weather station | 20 (38) | ||
|
|
Sensors placed on study site | 18 (34) | ||
|
|
Climatic chamber or laboratory | 18 (34) | ||
|
|
Locally installed weather station | 4 (8) | ||
|
|
Smartphone sensor | 2 (4) | ||
|
|
Satellite data | 2 (4) | ||
| Heat stress measurea | ||||
|
|
Wet bulb globe temperature | 14 (26) | ||
|
|
Heat stress index | 5 (9) | ||
|
|
Humidex | 2 (4) | ||
|
|
Others (universal thermal climate index, heating or cooling degrees, heat stroke index, heat stress days, heat stress level estimation, heat balance equation, extreme heat degree minutes, and physiological equivalent temperature) | 1 (2; each) | ||
|
|
None | 27 (51) | ||
| Method of analysis (statistical test)a | ||||
|
|
Regression (linear, logistic, and Cox) | 16 (30) | ||
|
|
Linear mixed effect model | 16 (30) | ||
|
|
Time-series analysis | 1 (2) | ||
|
|
t test (2-tailed or 1-tailed) | 21 (30) | ||
|
|
Correlation (Pearson, Spearman, etc) | 13 (25) | ||
|
|
ANOVA (one-way, repeated measures, and mixed design) | 14 (26) | ||
|
|
MANOVA | 1 (2) | ||
|
|
Nonparametric test (Wilcoxon U test and Kruskal-Wallis test) | 7 (13) | ||
|
|
Chi-square and Fisher Exact Test | 4 (8) | ||
|
|
Bland Altman plot | 5 (9) | ||
|
|
Spatial correlation | 1 (2) | ||
|
|
Cohen kappa | 1 (2) | ||
|
|
Descriptive analysis only | 5 (9) | ||
| Study objectives and use of wearablesa | ||||
|
|
Studies measuring the correlation of wearables’ data and environmental conditions | |||
|
|
|
Effect of heat on sleep | 7 (13) | |
|
|
|
Effect of heat on physical activity | 7 (13) | |
|
|
|
Effect of heat on heart rate | 10 (19) | |
|
|
|
Other physical responses to heat | 6 (11) | |
|
|
|
Occupational heat stress | 8 (15) | |
|
|
|
Effect of wildfires on physical activity | 1 (2) | |
|
|
Studies measuring the individual experienced temperature and comparing it to local or area measurements | 10 (19) | ||
|
|
Studies assessing the validity and applicability of wearables for their use in extreme weather | 14 (26) | ||
aMultiple characteristics may apply per study.