utilizing wearable technology to obtain body metrics is a trending phenomenon ( 3 , 5 ) .
the ease of obtaining individual measures makes wearable technology an attractive option , however , there is very little literature supporting the notion that these apparatuses can be used for field research .
hexoskin wearable technology shirt ( hxs ) is designed to measure several physiological variables including heart rate ( hr ) , respiratory rate ( rr ) , total energy expenditure ( ee ) , and total steps ( sc ) . in a laboratory - based investigation ,
the validity of this technology was compared with standard laboratory equipment at intensities up to 80% of the estimated mhr .
minimal variability was reported and consistency was accepted ( 4 ) . while there is evidence the hxs may be valid and reliable in a controlled laboratory setting , its application in an outdoor environment is largely unknown .
therefore , the purpose of this study was to utilize hxs technology to obtain data in various trail hiking situations .
we used this opportunity as a means to pilot test the hexoskin for collecting data in a real - life , outdoor setting .
ten individuals ( male n = 4 , female n = 6 ) volunteered to participate ( age = 2410 years , height = 1663 cm , mass = 6518 kg ) .
prior to involvement in the study , participants provided informed consent that was approved by the institutional review board ( southern utah university protocol # 13 - 092014 ) .
the protocol was a modification of a previous investigation completed by our research group ( 2 ) .
on the first day , volunteers completed two easy ( class i , yosemite decimal system ( yds ) ) 1.82 km ( 1.13 mile ) trail hikes at a self - preferred pace with a 15-minute rest period between trials .
altitude was measured at 5,446 feet above sea level ( 4400 heat stress tracker , kestrel , boothwyn , pa ) .
body metrics provided by the hxs ( hexoskin smart shirt , montreal , canada ) were hr , mhr , ee , rr , mrr , sc and cadence ( ca ) . the hxs collects data through a data collection device ( dcd ) that connects by a plug to the shirt itself .
the hxs dcd was connected when the subject began the easy trail hike and was disconnected when they reached the finish point .
systolic blood pressure ( sbp ) , diastolic blood pressure ( dbp ) and ratings of perceived exertion ( rpe ) was also taken .
sbp and dbp were measured with an automatic blood pressure device ( omron , bp742 , kyoto , japan ) .
spb , dbp , and rpe was taken at the very beginning ( directly before hxs activation ) and immediately at the finish for both easy trail hikes ( directly after the hxs was disconnected ) ( 1 ) .
on the second day , participants completed a strenuous ( class i , yosemite decimal system ( yds ) ) 1.82 km ( 1.13 mile ) uphill hike ( 17.6% grade ) .
initial elevation was 5,757 feet above sea level , and rose to 6,443 feet at the summit .
hxs , spb , dbp , and rpe measurements were taken at the beginning and end of both stages of the strenuous trail hike in a similar manner as the easy trail hikes .
the dependent variables of average hr , maximal hr , estimated calories , average breathing rate , maximal breathing rate , steps , cadence and rpe were analyzed between trail type ( initial easy trail , strenuous uphill , strenuous downhill ) using one - way repeated measures analysis of variance ( anova ) ( spss , ver .
intraclass correlation coefficients ( icc ) for each of the previously listed dependent variables as well as sbp , dbp , and rpe were determined using the reliability analysis : intraclass correlation coefficient option ( two - way mixed model , absolute agreement type ) in spss .
pearson product moment correlation coefficients ( r ) were determined for each trail condition for relationships between rpe and the dependent variables of sbp , hr , and mhr ; and between cadence and rr in spss using the bivariate correlation option and significance was accepted at p0.05 .
ten individuals ( male n = 4 , female n = 6 ) volunteered to participate ( age = 2410 years , height = 1663 cm , mass = 6518 kg ) .
prior to involvement in the study , participants provided informed consent that was approved by the institutional review board ( southern utah university protocol # 13 - 092014 ) .
the protocol was a modification of a previous investigation completed by our research group ( 2 ) .
on the first day , volunteers completed two easy ( class i , yosemite decimal system ( yds ) ) 1.82 km ( 1.13 mile ) trail hikes at a self - preferred pace with a 15-minute rest period between trials .
altitude was measured at 5,446 feet above sea level ( 4400 heat stress tracker , kestrel , boothwyn , pa ) .
body metrics provided by the hxs ( hexoskin smart shirt , montreal , canada ) were hr , mhr , ee , rr , mrr , sc and cadence ( ca ) .
the hxs collects data through a data collection device ( dcd ) that connects by a plug to the shirt itself .
the hxs dcd was connected when the subject began the easy trail hike and was disconnected when they reached the finish point .
systolic blood pressure ( sbp ) , diastolic blood pressure ( dbp ) and ratings of perceived exertion ( rpe ) was also taken .
sbp and dbp were measured with an automatic blood pressure device ( omron , bp742 , kyoto , japan ) .
spb , dbp , and rpe was taken at the very beginning ( directly before hxs activation ) and immediately at the finish for both easy trail hikes ( directly after the hxs was disconnected ) ( 1 ) .
on the second day , participants completed a strenuous ( class i , yosemite decimal system ( yds ) ) 1.82 km ( 1.13 mile ) uphill hike ( 17.6% grade ) .
initial elevation was 5,757 feet above sea level , and rose to 6,443 feet at the summit .
hxs , spb , dbp , and rpe measurements were taken at the beginning and end of both stages of the strenuous trail hike in a similar manner as the easy trail hikes .
the dependent variables of average hr , maximal hr , estimated calories , average breathing rate , maximal breathing rate , steps , cadence and rpe were analyzed between trail type ( initial easy trail , strenuous uphill , strenuous downhill ) using one - way repeated measures analysis of variance ( anova ) ( spss , ver .
intraclass correlation coefficients ( icc ) for each of the previously listed dependent variables as well as sbp , dbp , and rpe were determined using the reliability analysis : intraclass correlation coefficient option ( two - way mixed model , absolute agreement type ) in spss .
pearson product moment correlation coefficients ( r ) were determined for each trail condition for relationships between rpe and the dependent variables of sbp , hr , and mhr ; and between cadence and rr in spss using the bivariate correlation option and significance was accepted at p0.05 .
preferred hiking speed uphill was significantly slower ( 4.540.64 kmh ) than the easy trail ( 5.840.45 kmh , p<0.001 ) as well as on the downhill portion of the strenuous trail ( 5.630.71 kmh , p<0.001 ) .
no difference was observed between the hiking pace on the easy trail or the downhill portion of the strenuous trail ( p=0.80 ) .
conversely , ratings of perceived exertion were significantly greater during the uphill portion of the strenuous trail ( 13.72.4 ) compared to both the easy trail ( 9.91.3 , p<0.001 ) and the downhill portion ( 10.42.5 , p<0.001 ) . there was no difference in rpe between the easy trail or the downhill portion of the strenuous trail ( p = 0.40 ) .
the uphill trail elicited significantly elevated hr ( p=0.04 , see figure 1 ) and ee compared to the other hiking conditions ( p=0.02 , see figure 2 ) .
the downhill portion of the strenuous trail produced significantly increased sc compared to the easy trail only ( p=0.01 , see figure 3 ) . no differences were observed for any other condition ( p>0.05 ) .
additionally , downhill ca was significantly greater when compared to the strenuous uphill portion ( p=0.01 , see figure 4 ) , but no differences were observed for any other condition ( p>0.05 ) . no significant differences for trail type were noted for mhr ( up = 16822 beatsmin , easy = 16222 beatsmin , down = 14720 beatsmin ; p=0.38 ) , rr ( up = 3817 breathsmin , easy = 347 breathsmin , down = 3914 breathsmin ; p=0.45 ) or mrr ( up = 5417 breathsmin , easy = 6425 breathsmin , down = 6420 breathsmin ; p=0.31 ) .
significant icc was observed for dbp ( r = 0.80 , p = 0.02 ) , rr ( r = 0.98 , p = 0.01 ) , sc ( r = 0.97 , p = 0.01 ) , ca ( r = 0.97 , p = 0.01 ) and rpe ( r = 0.94 , p = 0.01 ) .
the icc for sbp ( r = 0.65 , p = 0.07 ) , hr ( r = 0.73 , p = 0.14 ) , mhr ( r = 0.65 , p = 0.91 ) , ee ( r = 0.53 , p = 0.25 ) , and maximal rr ( r = 0.68 , p = 0.09 ) were not significant .
ratings of perceived exertion were not significantly correlated with sbp , average hr , or mhr during any of the hiking stages ( see table 1 ) .
furthermore , there was no significant correlation between rr and ca in any of the hiking stages ( easy trail r = 0.19 , p = 0.49 ; strenuous uphill r = 0.52 , p = 0.16 ; strenuous downhill r = 0.25 , p = 0.49 ) .
the primary purpose of this investigation was to pilot test the hxs while obtaining physiological measurements in an outdoor trail hiking setting .
we hypothesized this technology would allow us to record measures that provided face validity . while measurements of hr and ee demonstrated expected values , it was not the case for mhr , rr , or mrr . additionally , while hxs measurements of rr , sc , and ca were found to be reliable , the measurements of hr , mhr , ee and mrr returned nonsignificant intraclass correlation coefficients . based on the physiological responses that we reported in our previous investigation ( 2 ) , we expected to observe a general increase during strenuous uphill hiking when compared with both the easy - rated trail and downhill portion of the strenuous trail .
while we did observe this phenomenon for hr and ee ( see figures 1 and 2 ) , it was not consistent for mhr , rr , or mrr .
the similar response in these variables to the different trail conditions may be due to the subjects self - selecting a slower pace for the strenuous uphill hike .
evidence for this is suggested by the lower cadence for the uphill hike ( fig .
4 ) coupled with a significantly greater rpe . additionally , while not significant , there was a trend for rpe obtained during the uphill strenuous portion of the hike to be correlated with maximal heart rate ( p=0.051 ) .
we have also observed that the hxs occasionally returned spurious values which could account for the results obtained .
this should be taken into account for investigators wishing to utilize hxs in the field . while we acknowledge that a great number of subjects are necessary to determine reliability measures for the hxs , the poor iccs in the current investigation are a concern
this is another factor that should be taken into consideration for researchers using this technology to obtain physiological measures in an outdoor field setting .
( 4 ) will be necessary to confirm that the hxs technology is valid and reliable in both laboratory and field - based settings .
the results of this study indicate that hxs technology may be utilized to provide select physiological data in an applied setting .
, hr did not register in 5 out of 10 subjects on the easy trail , and 8 out of 10 participants during the strenuous hike .
due to the nature of field testing , we were not cognizant of this fact until we attempted to download the data at a later time
. additionally , estimated ee values for the hexoskin appears to be linked to hr intensity .
while further testing is necessary to determine the validity of this algorithm , the returned ee will not be accurate in cases where hr does not register on the hxs device .
this study demonstrated there may be issues concerning the hxs s ability to measure and record data in a real - life setting .
this product should first be validated against established laboratory and field standards in order to confirm the manufacturer s claims that the hxs is indeed a useful tool for  physical training , sleep , and personal daily activities .  in conclusion , we recommend that validity and reliability be established before hxs are utilized for research purposes in a field - based environment .
 use of wearable technology to obtain various body metrics appears to be a trending phenomenon . 
 however there is very little literature supporting the notion that these apparatuses can be used for research purposes in the field . 
 the purpose of this study was to utilize hexoskin wearable technology shirts ( hxs ) to obtain data in a pilot study using a trail hiking situation . 
 ten individuals ( male , n = 4 , female n = 6 ) volunteered to participate . on the first day 
 , volunteers completed two approximately flat trail hikes at a self - preferred pace with a 15-minute rest between trials . on the second day 
 , participants completed a strenuous uphill hike ( 17.6% grade ) with a 15-minute rest at the summit and then completed the downhill portion . 
 body metrics provided by the hxs were average heart rate ( hr ) , maximal hr ( mhr ) , total energy expenditure ( ee ) , average respiratory rate ( rr ) , maximal respiratory rate ( mrr ) , total steps ( sc ) , and cadence ( ca ) . 
 other measurements obtained were systolic and diastolic blood pressure ( sbp , dbp ) , and ratings of perceived exertion ( rpe ) . 
 data were analyzed using both one - way repeated measures analysis of variance ( anova ) with significance accepted at p0.05 and intraclass correlation coefficients ( icc ) for each variable . both were determined using statistical package for the social sciences software ( spss ) . 
 no significant differences for trail type were noted for mhr ( p=0.38 ) , rr ( p=0.45 ) or mrr ( p=0.31 ) . 
 the uphill trail elicited significantly elevated hr ( up=15424 bpm , easy=11811 bpm , down=12919 bpm ; p=0.04 ) and ee ( up=25178 kcal , easy=12438 kcal , down=17152 kcal ; p=0.02 ) . 
 significant icc were observed for dbp ( r = 0.80 , p = 0.02 ) , rr ( r = 0.98 , p = 0.01 ) , sc ( r = 0.97 , p = 0.01 ) and rpe ( r = 0.94 , p = 0.01 ) . 
 non - significant correlation were noted for uphill rr vs ca ( r=0.51 , p=0.16 ) or rpe vs sbp ( r=0.03 , p=0.94 ) , hr ( r=0.60 , p=0.12 ) , and mhr ( r=0.70 , p=0.051 ) . 
 we utilized hxs to provide physiological data in an applied setting . 
 it should be noted that hr did not register in 5 out of 10 subjects on the easy trail , and 8 of 10 participants during the uphill hike . additionally , estimated ee appears to be linked to hr intensity . 
 future investigations taken in an outdoor environment should take these findings into consideration . 