“…Most field studies (20 out of 32) were conducted in low- or middle-income countries ( 18 , 20 – 22 , 24 , 27 , 29 – 31 , 33 , 37 , 38 , 40 – 42 , 45 – 47 , 49 ), with only 11 studies from Europe, the USA, and Australia/New Zealand ( 19 , 23 , 25 , 26 , 28 , 34 , 35 , 39 , 43 , 44 , 48 ) and 1 multicenter study ( 36 ). Three studies were qualitative, based on interviews or focus groups ( 28 , 33 , 43 ), while the other studies were quantitative with 27 cross-sectional and 2 longitudinal studies ( 26 , 42 ) and provided an estimation of the association between heat and labor productivity measured in the field or perceived by workers.…”