Can People Smell Your Stress Sweat?What the Skydiver Study Found

Stress sweat has its own pattern, and it does more than dampen your shirt. A review of “psychological sweating” found it shows up most on the palms, soles, face and underarms.¹ In the underarms, stress drives the apocrine glands, which leads to more sweat and more odor, a pattern that starts at puberty.¹

The skydiver study

Researchers at Stony Brook University collected underarm sweat from 144 people on their first tandem skydive, jumping from 13,000 feet with a full minute of free fall. They also collected sweat from the same people running on a treadmill for the same length of time, at the same time of day.²

What they tested	What happened
Pooled sweat given to people lying in a brain scanner (16 people, then 16 more in a repeat with new donors)2	Skydive sweat activated the amygdala, a fear center. Treadmill sweat didn’t2
Could 16 people tell the two sweats apart by smell?2	No. They did no better than chance2
Did the stress sweat change how people read faces?2	Yes. It sharpened how they read ambiguous facial expressions2

The researchers noted one wrinkle: the pads stayed on through landing, when relief or thrill sometimes followed the fear, so the signal may not be pure fear.²

The bigger picture

A 2017 meta-analysis pooled 26 studies with 1,652 people on whether fear, stress and anxiety can pass from one person’s body odor to another’s. It found a small-to-moderate effect and no sign of publication bias.³ Most sweat donors were men (66%) and most receivers were women (69%), and the authors didn’t rate how well each study was designed.³

What this means on a stressful day

• Nobody can name your fear by sniffing. In the skydiver study, people couldn’t consciously tell stress sweat from exercise sweat.² Any effect works below awareness and is modest.³
• The part you can manage is the underarm itself. Stress raises sweat and odor there.¹ An antiperspirant handles wetness; a deodorant handles smell. See the difference between antiperspirant and deodorant and clinical-strength label claims.
• More help: why you sweat so much when you’re nervous, why you still smell after a shower and how to stop yellow armpit stains.

Try: “Before presentations my underarms get soaked and I notice a smell, even with deodorant. Would a stronger antiperspirant at night help, or is this worth looking into further?”

Arms Up covers this in Chapter 10, “Hot Under Pressure,” in a section called “Can People Smell Stress?” Its Fresh Log asks you to mark high-pressure days and note whether you were wet, aware of a smell, or both. A couple of weeks of entries shows whether your stress shows up as sweat, as odor, or as worry about odor with neither present. See the book.