Daily Heart Rate Variability is Higher in Regular Exercisers Versus Matched Non-Exercisers with Similar Chronic Stressor Profiles During the COVID-19 Pandemic

The COVID-19 pandemic increased stress levels and created new health issues amongst individuals of all ages, genders, socioeconomic status, and occupations (da Silveira et al., 2020). The purpose of this research project was to examine differences in acute daily stress using measures of daily morning heart rate (HR), the root mean square of successive differences between normal heartbeats (RMSSD), and a proprietary index of heart rate variability (HRV) compared between matched groups of exercisers and non-exercisers with similar levels of chronic stressors. The sample consisted of 20 adult subjects (10 exercisers, 10-matched non-exercisers), including ten males and ten females with a mean body mass index (BMI) of 26.6±12.87 (females = 27.53±5.34, males = 24.77±3.55). The sample was recruited from the Pueblo, Colorado community and Colorado State University Pueblo and consisted of local community members and faculty, staff, and student body members. The participants recorded their daily morning heart rate at home using a Polar heart rate monitor and the Elite HRV phone application. Chronic stressor load was measured using the Trier Inventory of Chronic Stress (TICS) (2004) at baseline, 3 and 6 weeks. The study occurred during the COVID-19 Pandemic between September 2020 and December 2020. The regular exercise group experienced a significantly lower mean HR (p < 0.05), significantly higher mean RMSSD (p < 0.05), and mean HRV (p < 0.05) than the non-exercisers during the study period, with no significant differences between the groups in mean chronic stressor level as evaluated by the TICS. This research provides further evidence that exercise offers a stress-buffering effect during periods of high chronic stress, such as experienced during the COVID-19 Pandemic.