Effort-reward imbalance in the workplace has been related with poor mental and physical health and a variety of negative organisational outcomes including increased rates of absenteeism, presentism, and job turnover, but the model has rarely been assessed using experimental designs. Female participants (N = 90) were randomly assigned to positive verbal feedback and no verbal feedback conditions. Within a simulated office environment, all participants were under time-pressure to successfully complete computer-based tasks in order to gain remuneration. Positive verbal feedback about task performance was provided to improve the aspect of 'esteem reward' (while keeping effort constant) using a mixed within-between subjects design. Psychological, behavioural (task performance), and physiological (heart rate variability, salivary alpha amylase) measures assessed the impact of the positive verbal feedback. Participants receiving the esteem manipulation did not self-report increased rewards, but performed moderately better on the task, and had more adaptive physiological reactivity in the high reward versus the standard condition. Similar to recent research our findings highlight the importance of concurrent assessments of both self-reports and physiological measures of stress, and suggest that positive verbal feedback about work performance can elicit adaptive physiological responses and may also positively influence task efficacy.