People with postural tachycardia syndrome (POTS) who complain of ‘brain fog’ could be experiencing the effects of reduced brain blood flow and prolonged reaction times, Australian researchers say.

Royal Adelaide Hospital cardiologists and colleagues performed a 30-minute cognitive stress test on 22 patients with POTS (mean age 29, 86% female) and compared their outcomes with those for 18 matched, healthy controls (mean age 28, 72% female).

A range of physiological and cognitive tests, plus completion of various questionnaires, were performed at baseline and after the prolonged cognitive stress test that involved complex pattern-matching tasks and rapid attention-switching tasks.

To reduce orthostatic stress, which is known to affect cerebral blood flow in people with POTS, the stress test was carried out with the participant seated at a desk.