Noninvasive Estimation of Hydration Status in Athletes Using Wearable Sensors and a Data-Driven Approach Based on Orthostatic Changes

Fahad Kamran,Kathleen H Sienko,Victor C Le,Jenna Wiens,Adam Frischknecht

doi:10.3390/s21134469

Abstract

Dehydration beyond 2% bodyweight loss should be monitored to reduce the risk of heat-related injuries during exercise. However, assessments of hydration in athletic settings can be limited in their accuracy and accessibility. In this study, we sought to develop a data-driven noninvasive approach to measure hydration status, leveraging wearable sensors and normal orthostatic movements. Twenty participants (10 males, 25.0 ± 6.6 years; 10 females, 27.8 ± 4.3 years) completed two exercise sessions in a heated environment: one session was completed without fluid replacement. Before and after exercise, participants performed 12 postural movements that varied in length (up to 2 min). Logistic regression models were trained to estimate dehydration status given their heart rate responses to these postural movements. The area under the receiver operating characteristic curve (AUROC) was used to parameterize the model’s discriminative ability. Models achieved an AUROC of 0.79 (IQR: 0.75, 0.91) when discriminating 2% bodyweight loss. The AUROC for the longer supine-to-stand postural movements and shorter toe-touches were similar (0.89, IQR: 0.89, 1.00). Shorter orthostatic tests achieved similar accuracy to clinical tests. The findings suggest that data from wearable sensors can be used to accurately estimate mild dehydration in athletes. In practice, this method may provide an additional measurement for early intervention of severe dehydration.

Highlights

Published: 29 June 2021Exercise-induced dehydration is typically a result of insufficient replenishment of fluids lost mainly to sweat
We focused on the relative change in heart rate evoked by the transitions to standing during the postural movements
As postural movements that were labeled “dehydrated” only occurred after bouts of exercise, we focused our evaluation on post-exercise postural movements to ensure that the model was learning the effect of dehydration rather than exercise

Summary

Introduction

Published: 29 June 2021Exercise-induced dehydration is typically a result of insufficient replenishment of fluids lost mainly to sweat. Dehydration of up to 2 to 3% of one’s body weight in athletic settings is common for healthy individuals, especially when performing in the heat [1]. Laboratory-based approaches for monitoring dehydration status (e.g., serum chemistry panels), while accurate, require specialized equipment and can be difficult to administer during athletic activities due to inadequate portability [10,14,15]. Multiple types of wearable sensors have been used to estimate hydration status within research settings. Dehydration has been accurately estimated using sensors that analyze different biomarkers of sweat secretion or properties of the skin (e.g., temperature and impedance) that are correlated with hydration

Methods

Discussion

Conclusion