Accuracy of a heart rate monitor for calculating heart rate variability parameters in exercising horses

Heart rate is evaluated in exercising horses to monitor the level of fitness to exercise, and it is usually acquired using heart rate monitors (HRM) or telemetric electrocardiograms (ECG). While HRM are commonly available and easy-to-use for horse's owners, ECG is a more expensive equipment requiring user's experience. Interest for heart rate variability (HRV) in horses is increasing for both research and clinical purposes. HRV is usually calculated from interbeat intervals (IBI) obtained by ECG. The aim of this study was to determine the accuracy of an HRM to detect IBI for the calculation of HRV in both resting and exercising horses. Simultaneous ECG and HRM recordings were performed on 13 horses and ponies under normal training conditions for at least 45 minutes. IBI from ECG were corrected using a dedicated software. IBI from HRM were exported without correction. Two HRV-parameters were calculated on both recordings for resting and exercising periods: the standard deviation of R-R intervals (SDRR) and the root mean square of successive differences (RMSSD). Agreement and concordance between the two systems were determined using Bland-Altman plot and Lin's correlation coefficient, respectively. Effects of variables were consequently assessed. For both HRV-parameters during resting and exercising periods, the means of the differences between the two systems were lower than 0.47 ms with a correlation coefficient higher than 0.999. Height, weight and body condition score had no effect on the results. The studied HRM could be of interest as easy-to-use device for obtaining HRV-parameters SDRR and RMSSD in resting and exercising horses.

Acute effects of Zamzam water on blood pressure and heart rate variability

Objective:

There is a lack of studies exploring the effects of Zamzam water on human physiology. The present study determined the effects of Zamzam water on blood pressure and heart rate variability (HRV).

Methods:

This comparative interventional study was conducted at the Department of Physiology, of our university in March 2018. A total number of 97 female subjects drank 500 ml of either Zamzam water or mineral water in one minute. Finometer Pro and PowerLab (ADInstruments^R) with ECG electrodes through bioamplifier and attached finger pulse transducer were used to collect data at the baseline (for five minutes), during (for one minute) and after the drink (for five minutes). Paired and uunpaired student’s t-test, one-way ANCOVA and one-way repeated measure ANOVA were used for analysis. Blood pressure parameters were followed minute by minute and HRV parameters were compared as a 5-minute of baseline segment to 5-minute post drink segment.

Results:

Within-the-group comparison exhibited significant increases in blood pressure parameters (systolic, diastolic, pulse and mean arterial pressure), over a 5-minute post-drinking period in both groups. Zamzam water caused a significant increase in SDRR (an indication of overall HRV) and RMSSD (an indication of vagal activity) as compared to baseline.

Conclusion:

Both drinks cause a significant increase in systolic, diastolic, pulse and mean arterial pressure within five minutes post-drinking period. Zamzam water produce a significant increase in cardiac vagal tone but has no effect on cardiac sympathetic activity. Mineral water has no significant effect on both, cardiac vagal and sympathetic activity.