Table 2 Summary of 5-min resolution of (a) personal wet-bulb globe temperature (WBGT) exposures during different periods (excluding rainy periods) calculated with Liljegren equations using inputs from personal sensors except wind speeds and (b) heart rate variability (HRV) indicators in the non-sleeping periods from RootiRx®.

From: An innovative method of evaluating the association of heat exposure and heart rate variability in a panel of agricultural workers with small and lightweight personal sensors

(a)

Personal exposures

Pear orchards (8 participants)

Rice seedling field (6 participants)

Greenhouse (11 participants)

Overall (25 participants)

WBGT (°C) (Entire monitoring period)

Mean ± SD

26.2 ± 2.1

28.4 ± 4.7

26.4 ± 5.9

26.8 ± 4.8

Max

36.0

48.2

47.3

48.2

Sample size

12,517

8778

17,609

38,904

WBGT (°C) (non-sleeping period)

Mean ± SD

26.6 ± 2.1

29.9 ± 4.1

27.9 ± 6.1

28.0 ± 5.0

Max

36.0

48.2

47.3

48.2

Sample size

5486

4682

10,529

20,679

WBGT (°C) (working period)

Mean ± SD

27.0 ± 1.7

31.9 ± 3.7

32.6 ± 6.3

30.4 ± 5.1

Max

35.2

48.2

47.3

48.2

Sample size

4984

3497

4856

13,337

WBGT (°C) (outdoor working period)

Mean ± SD

26.7 ± 2.5

32.9 ± 4.0

35.5 ± 4.7

32.9 ± 5.3

Max

35.2

48.2

47.3

48.2

Sample size

1460

2198

3440

7098

WBGT (°C) (indoor working period)

Mean ± SD

27.2 ± 1.2

29.6 ± 1.4

25.4 ± 3.2

27.1 ± 2.3

Max

31.3

39.5

38.2

39.5

Sample size

3422

894

1371

5687

WBGT (°C) (outdoor transportation during work, such as motorcycles)

Mean ± SD

26.4 ± 1.9

31.8 ± 2.4

36.8 ± 4.2

31.1 ± 3.6

Max

30.4

40.1

42.9

42.9

Sample size

102

396

39

537

WBGT (°C) (indoor transportation during work, such as trucks)

Mean ± SD

N/A

27.7 ± 1

28.7 ± 0.7

28.1 ± 1.0

Max

N/A

28.8

29.4

29.4

Sample size

0

9

6

15

Ambient WBGT (°C)a

Mean ± SD

30.0 ± 3.4

31.0 ± 2.2

32.3 ± 3.3

31.1 ± 2.9

Max

41.9

41.2

43.1

43.1

Sample size

893

1070

956

2919

(b)

HRV indices

Pear orchards 8 participants (sample size = 5486)

Rice seedling field 6 participants (sample size = 4682)

Greenhouse 11 participants (sample size = 10,529)

Overall 25 participants (sample size = 20,697)

 

SDNN

52.5 ± 29.5

49.8 ± 30.8

59.3 ± 26.3

55.3 ± 28.5

 

RMSSD

22.6 ± 13.9

24.9 ± 16.7

28.2 ± 15.1

26.0 ± 15.4

 

LF/HF

4.0 ± 3.1

3.8 ± 3.3

3.9 ± 3.0

3.9 ± 3.1

 

LF

1250.6 ± 2221.5

1259.9 ± 1705.4

1455.6 ± 1482.4

1357.0 ± 1758.9

 

HF

613.1 ± 1115.3

479.7 ± 713.7

587.3 ± 724.8

569.8 ± 845.4

 

VLF

2549.1 ± 3866.9

2284.5 ± 3436.2

2928.8 ± 3083.0

2682.4 ± 3397.0

 

TP

4508.5 ± 6624.6

4115.4 ± 5340.6

5056.1 ± 4772.4

4702.7 ± 5461.0

 

HR

83.5 ± 11.8

94.1 ± 15.8

88.6 ± 16.3

88.5 ± 15.6

 
  1. aThe ambient 5-min WBGT levels during the working period are presented, obtained from the measurements of the on-site fixed-location weather station serving as inputs to the Liljegren equations.
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