Cortisol is the hormone your body releases when you’re stressed. It’s useful in short bursts — like when you need to focus before a test — but when it stays high, it wears you down mentally and physically. The good news is that nature can bring it down, and faster than you might think.
A peer-reviewed study published in Frontiers in Psychology found that spending at least 20 to 30 minutes in a nature setting was associated with the biggest drop in cortisol levels. After that window, stress reduction continued, but more slowly. So the 20-to-30-minute mark appears to be a kind of sweet spot for getting the most out of a nature break.
Harvard Health highlights this same research, noting that the stress-reduction benefit levels off a bit after that initial stretch — meaning you don’t necessarily need to spend hours outside to feel a difference. Even sitting or walking somewhere that gives you a sense of nature counts. That could be a park, a trail, a tree-lined street, or a quiet patch of grass.
Research has also found that natural settings tend to be more effective than built environments — like sidewalks or parking lots — at reducing both cortisol and another stress marker called alpha-amylase. In other words, the greener and more natural, the better.
The single most important takeaway: if you’re feeling overwhelmed or burnt out, a 20-to-30-minute walk or sit in a park isn’t just a nice idea — it’s something science has actually measured as effective for many people. Make it a regular habit, not just a last resort.