PurposeThe purpose of this study is to identify the perception of workers before, during and after the implementation of changes derived from the lean manufacturing (LM) technique called value stream mapping (VSM) analysis and the causes that lead to this perception.Design/methodology/approachA qualitative methodological research design was adopted, using individual transcribed and coded interviews as the primary method of data collection.FindingsAt the beginning of the VSM changes, this study found strong denial and resistance emotional responses from workers due to the uncertainty and stress generated. The main cause of this resistance was their lack of understanding of the VSM analysis process presenting technical concepts, due to their educational level and the lack of a pre-existing organisational culture oriented toward continuous improvement. However, in the last stage of change, it is found that the workers accepted the new improvement proposals without resignation, improving their productivity and work performance because they saw and understood the improvements as effective.Practical implicationsThis study will enable those responsible for organisations to anticipate the negative reactions that may arise from the organisational changes stemming from the implementation of VSM improvements. In addition, it adds new knowledge bases to the literature on the emotional consequences for employees during LM changes through VSM.Originality/valueThis study provides a qualitative analysis of the perceived emotional impact on workers that participated in LM techniques, in this case, focused on VSM analysis. It is an exploratory study that serves as a foundation for future research in the quantitative field.