Early observational study for non-invasive measurements of exercise-induced fatigue in adult men -
Exploration of candidate sensors

Exercising at the proper intensity is important because intensities too low
decrease the effectiveness of training and intensities too high increase the
risk of overtraining and injuries. Currently, athletes are guided by heart rate
sensors; although these heart sensors can measure the heart rate accurately,
the heart rate itself is a poor indicator for the intensity of a training for
an individual. Ideally, one would use the golden standards within exercise
physiology, blood lactic acid and breath gas analysis (BGA), to determine the
ideal exercise intensity. These measurements, however, are burdensome to
perform, require specialized expertise, and are costly.
In the literature several non-invasive and continuous parameters have shown a
correlation with BGA and/or lactic acid measurements. Ares Analytics believes
that by combining multiple sensors/parameters in one system, the correlation or
agreement with the values of the gold standard techniques can be improved.
In this study, participants will perform three different exercise test on a
bicycle ergometer. During the test the golden standards BGA and lactic acid
will be measured in parallel with a set of candidate sensors to investigate the
relation and develop an algorithm.
The study serves as the first step for Ares Analytics to develop a future
wearable that can provide information on BGA and lactic acid measurements based
on continuous, non-invasive measurements during physical exercise in healthy
subjects.

The primary objective of this study is to determine which candidate sensors
alone or in combination are most correlated with the results from the gold
standard technique breath gas analysis and blood lactic acid; and to develop an
algorithm that leads to a close agreement between the values by these candidate
sensors and the actual values measured by these golden standards.

The present study is designed as a single-center cross-sectional study in three
groups of healthy, adult men. There will be three subject groups with nine
participants per group; athletic with low BMI, athletic with high BMI, and
non-athletic with low BMI. Each subject will be asked to perform three
different exercise tests in total while various measurements are performed. The
study is performed within the facilities of the department of Rehabilitation &
Sports medicine at the University Medical Center Utrecht with specialized
investigators.

Healthy, adult men will visit the UMCU three times over a period of two to four
weeks. Each visit will take approximately one hour and includes an exhausting
exercise on the ergometer bicycle. All activities are closely monitored by a
sports physician and prior to the first exercise the potential health risks
will be evaluated based on a standardized questionnaire and examination. During
the exercise the subject will wear a mask for breath analysis and he will wear
a number of non-invasive sensors (both for safety (e.g. ECG on the chest) and
the candidate sensors on the upper legs). In addition, per exercise test, a
maximum of 22 droplets of blood will be taken from the earlobe for the lactic
acid analysis.
Subjects will be reimbursed for costs made as a results of study participation
(e.g. travel and parking costs and money for the 2nd and 3rd test). In
addition, the subjects will be informed of their fitness, VO2max score,
including advice for their training schedules, and given general feedback about
whether or not abnormalities were found with their ECG measurements.