Mindfulness-based programs (MBPs) vary in length of mindfulness practices included. It might be expected that longer practice leads to greater benefits in terms of increased mindfulness and decreased psychological distress. However, the evidence for such dose–response effects is mixed and generally does not support such strong causal conclusions given its correlational nature. Therefore, the current study sought to clarify which length of mindfulness practice led to greater benefits using an experimental design.
Participants (N = 71; 71.8% female), who were healthy adults with limited prior mindfulness practice experience, were randomized to either (i) four longer (20-min) mindfulness practices, (ii) four shorter (5-min) mindfulness practices, or (iii) an audiobook control group. All sessions were held in-person over a 2-week period, each group listened to the same total length of material each session, and participants refrained from formal mindfulness practice outside of sessions.
Both longer and shorter practice significantly improved trait mindfulness, depression, anxiety, and stress compared with controls. Unexpectedly, shorter practice had a significantly greater effect on trait mindfulness (d = 2.17; p < .001) and stress (d = − 1.18; p < .01) than longer practice, with a trend in the same direction for depression and anxiety. Mediation analysis findings were mixed.
Even a relatively small amount of mindfulness practice can be beneficial and shorter practices may initially be more helpful for novice practitioners in MBPs with minimal teacher contact. Further research is needed to examine such dose–response effects when teacher involvement is greater and over the longer term.
ClinicalTrials.gov pre-registration identifier: NCT03797599