Five minutes of contact with grass indoors lowered blood pressure and reduced anxiety
STUDY: Li Weinan et al, J Behav Ther Exp Psychiatry 2026
STUDY TYPE: Crossover study
FUNDING: Independent
Background
Most adults now spend over 85% of their waking hours indoors, with screen time filling much of what used to be time outdoors. Disconnection from nature raises stress and anxiety, but getting outside isn’t easy. This study tested whether something simpler — holding grass indoors for five minutes — could help.
The Study
- 44 young Chinese female college students, mean age 21.
- Within-subject design: participants touched either grass or a wood block for 5 minutes each in a controlled lab setting.
- Physiological outcomes: blood pressure and EEG brainwave activity. Psychological outcomes: anxiety scale (STAI) and a comfort/relaxation scale (SDM).
Diastolic blood pressure dropped significantly after grass contact compared to wood. Anxiety scores (STAI) fell meaningfully as well: grass 39.3 versus wood 41.5. Participants also rated themselves as more comfortable and relaxed after touching grass. EEG alpha and beta activity trended upward with grass but didn’t reach statistical significance, suggesting the psychological effects outpaced the neural ones in this short window.
Limitations
Small, all-female. The grass and wood stimuli differed in softness and temperature, which weren’t controlled for.
Practice Implications
- Touch grass.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
