Psychometric curves generated by a forced-choice assessment of ambiguous threat show sharpened discrimination between threat and non-threat while breathing stress-derived sweat.

<p>For each participant, data for each condition (STRESS, EXERCISE) were fitted with the sigmoid function, where <i>p</i>₀ and <i>p</i>₀+Δ<i>p</i> define upper and lower asymptotes, A₀ is the inflection point, and σ defines slope. Significant differences between conditions were seen for slope, with individuals under the STRESS condition more closely approximating ideal perceptual discrimination, shown by the dotted line.</p

Gas chromatography mass spectroscopy analyses of exercise sweat samples were used to validate that our collection and aqueous extraction methods were capable of sampling over hydrophobic (steroid) components in human apocrine sweat.

<p>Mass spectrum of retention time 19.512 minutes shows the presence of human steroids found in apocrine sweat.</p

Gas chromatography mass spectroscopy analyses of exercise sweat samples were used to validate that our collection and aqueous extraction methods were capable of sampling over hydrophobic (steroid) components in human apocrine sweat.

<p>Mass spectrum of retention time 20.655 minutes shows the presence of human steroids found in apocrine sweat.</p

Gas chromatography mass spectroscopy analyses of exercise sweat samples were used to validate that our collection and aqueous extraction methods were capable of sampling over hydrophobic (steroid) components in human apocrine sweat.

<p>Total ion count gas chromatography trace of aqueous human sweat extract shows the presence of cholesterol, which is hydrophobic.</p

During the fMRI scans, participants' breathing was synchronized via a continuously expanding and contracting circle (a), which cued inhalation and exhalation, respectively.

<p>Stress and exercise sweat were presented in a randomized block design, with each 20s block comprised of four inhalations-exhalations (b), timed to a five-second cycle.</p