The aim of this study was to examine the effect of 10 minutes of heart rate variability (HRV) biofeedback on cognitive performance and affect scores during induced stress. Eighteen healthy male volunteers (aged 23-41 years) exposed to workrelated stress, were randomised into an HRV biofeedback intervention (BIO) and a comparative intervention group (COM). Subjects completed a modified Stroop task, which included having to mentally count 18 white squares randomly presented between colour words, before and after a 10-minute intervention. Subjects also completed questionnaires to rate their anxiety. BIO subjects improved their reaction times and consistency of responses, and made fewer mistakes in counting squares during the modified Stroop task. They also felt more relaxed, less anxious and less sleepy than the COM subjects. In conclusion our results suggest that short duration HRV biofeedback is associated with improved cognitive performance while concurrently aiding relaxation.

The assessment and management of psychosocial stress is a challenging but important component of effective comprehensive lifestyle interventions for the management of noncommunicable disease. It is, therefore, important for the sports and exercise physician to have an understanding of the therapeutic use of HRV modulation, both in the reduction of stress and in the management of chronic disease.

This pilot study examines the effect of heart rate variability (HRV) biofeedback on measures of electroencephalogram (EEG) during and immediately after biofeedback. Eighteen healthy males exposed to work-related stress, were randomised into an HRV biofeedback (BIO) or a comparative group (COM). EEG was recorded during the intervention and during rest periods before and after the intervention. Power spectral density in theta, alpha and beta frequency bands and theta/beta ratios were calculated. During the intervention, the BIO group had higher relative theta power [Fz and Pz (p < 0.01), Cz (p < 0.05)], lower fronto-central relative beta power (p < 0.05), and higher theta/beta [Fz and Cz (p < 0.01), Pz (p < 0.05)] than the COM group. The groups showed different responses after the intervention with increased posterior theta/beta (p < 0.05) in the BIO group and altered posterior relative theta (p < 0.05), central relative beta (p = 0.06) and central-posterior theta/beta (p < 0.01) in the post-intervention rest period. The findings of this study suggest that a single session of HRV biofeedback after a single training session was associated with changes in EEG suggestive of increased internal attention and relaxation both during and after the intervention. However, the comparative intervention was associated with changes suggestive of increased mental effort and possible anxiety during and after the intervention.