Table 1 Descriptive statistics table of merged datasets with two main pools of variables.

Environmental variables

Observed

Air velocity

m/s

407

1.3

0.83

0.1

0.7

1.7

5.2

Air temperature

°C

407

33

3.8

22

31

36

45

Relative humidity

%

407

28

23

0

9.9

41

88

Black globe temperature

°C

407

38

4.9

15

34

41

52

Modelled

Solar radiation

J/m²

407

6e⁶

4.37e⁶

3.29e⁵

2.27e⁶

8.33e⁶

2e⁷

Water vapour pressure

hPa

407

14

10

0

5

20

53

Calculated

Universal thermal climate index

°C

407

33

3.9

20

31

35

51

Apparent temperature

°C

407

33

4.4

19

31

36

51

Heat index

°C

407

33

4.5

21

30

36

71

Wet bulb globe temperature

°C

407

24

3.4

15

22

27

35

Physiological variables

Observed

Heart rate

bpm

353

106

13

65

97

115

147

Skin temperature

°C

353

37

1.1

32

36

38

40

Tympanic temperature

°C

89

37

0.35

36

37

37

38

Calculated

Core temperature

°C

299

38

0.31

37

37

38

39

Physiological strain index

NA

299

3.8

1

1.4

3.1

4.5

7.1

Observed

Gestational age

weeks

407

27

6.9

12

23

33

41

Fitness status, 6 min walking test

m

407

498

74

135

461

544

687

Estimated

Metabolic rate

kcal/kg/h

357

3.2

0.85

1.9

2.3

3.8

5.2