High‐intensity physical activity seems to be associated to a higher basal parasympathetic activity and to a reduced OSDI score in young adults

Abstract

Aims/Purpose: To identify if the habitual practice of physical activity is associated to the basal parasympathetic activity and to dry eye disease‐related symptoms.Methods: Eleven adults (82% women; age: 30.7 ± 4.9 years; BMI 22.2 ± 1.9 kg m−2) responded the Ocular Surface Disease Index (OSDI), the Dry‐Eye 5 (DEQ5) and the International Physical Activity (IPAQ) questionnaires. Subsequently: a) the inferior tear meniscus height (ITMH) and the automated non‐invasive break‐up time (NIBUT) of both eyes; b) the heart rate variability (Polar H10 chest band; Kubios HRV software) and, simultaneously, the Schirmer test; and, c) the tear film break‐up time (BUT) were measured. Correlational analyses were performed among the measured variables.Results: The total weekly physical activity was of 3420 ± 3302 metabolic equivalents (MET) min−1 week−1, with a weekly high‐intensity physical activity (HIPA) of 567 ± 661 MET min−1 week−1. The OSDI score was 14.1 ± 8.3, the DEQ5 score was 7.2 ± 4.8, the ITMH was 229.3 ± 40.7 (OD) and 252.7 ± 51.2 (OS) μm, the NIBUT was 8.5 ± 5.7 (OD) and 8.8 ± 6.1 (OS) s, and the BUT was 9.7 ± 4.1 (OD) and 8.3 ± 3.9 (OS) s. Two surrogates of the parasympathetic activity (the PNS index, and the root‐squared mean of successive standard deviations, RMSSD) showed values of 0.762 ± 1.899 and 60.1 ± 37.8 ms, respectively. The HIPA showed a direct correlation with the parasympathetic activity surrogates (r = 0.784, p = 0.004, PNS index; r = 0.737, p = 0.009, RMSSD). Similarly, the HIPA showed an inverse correlation with the OSDI (r = −0.759, p = 0.006) and the DEQ5 (r = −587, p = 0.07). No other correlations were found, neither among the HIPA nor among the parasympathetic surrogates with the ITMH, the NIBUT, the BUT or the Schirmer test.Conclusions: These preliminary results suggest that in young subjects HIPA seems to be associated to an increased basal parasympathetic activity and to a reduced perception of dry‐eye symptomatology.