The study by Dr Wendy Hall and Dr Sarah Berry, both from the School of Life Course Sciences, measured HRV in participants undergoing a mental stress challenge and saw improved measures of HRV in participants who had been replacing typical snacks with almonds over a six-week period.

The study was funded by the Almond Board of California.Mental stress is among the psychosocial factors thought to contribute to cardiovascular disease (CVD) risk.

Heart rate variability (HRV), a measure of the fluctuation in time intervals between consecutive heartbeats, is an important indicator of the cardiovascular system’s response to stress and it is thought that lifestyle factors including physical activity and diet might impact HRV. Higher HRV represents greater adaptability of the heart in response to environmental and psychological challenges, while low HRV is linked to cardiovascular disease and sudden cardiac death.

This new research finding was part of the ATTIS study, a 6-week randomized control, parallel-arm trial, where participants with above average cardiovascular disease risk consumed a daily snack of almonds or a calorie-matched control snack providing 20% of each participants’ estimated daily energy needs.

In this study, researchers measured participants’ real-time heart rate (HR) and heart rate variability (HRV) at rest (lying down for 5-minute periods) and during a Stroop test (in which participants were asked to read colored words i.e. say “red” in a green font) to simulate short period of mental stress.During acute mental stress, participants in the almond group showed better heart rate regulationcompared to the control group, indicated by statistically significant differences in high frequency power, which specifically evaluates beat-to-beat intervals (a measure of HRV).