Methods of Assessing Sweat-Electrolyte Testing (MAST)

If you agree to be in this study, you will be asked to report to our exercise science research center for two total visits (2 separate trials separated by at least 4 days) and the total time commitment for this study will be approximately 5 hours. Prior to each trial, you will be provided with urine jugs and food/fluid logs to record food and drink intake for 24hr. You will be asked to log food/fluid intake 24hr leading into trials. We ask that you match your diet for both trials, as much as possible. Also, we ask that you match caffeine consumption prior to trials. Lastly, we ask that you refrain from strenuous exercise and alcohol consumption for at least 12hrs leading into trials. Either of these exclude your participation in the study for safety reasons. You will be asked to provide a small urine sample upon arrival to the lab before trials. The purpose of this is to verify hydration prior to exercise in the heat. If you are not hydrated upon arrival, you will be provided and asked to drink 16oz (a bottle) of water prior to the trial. Next, you will be seated, have 2 electrodes placed on your inner forearm and researchers will apply electrical stimulation for about 5min. Typically, people feel slight tingling or nothing at all during this procedure. This is a passive way of making you sweat on your forearm. Sweat will then be collected via a small disc applied to your forearm. Immediately following this, you will have your nude body mass measured and you will be instrumented with a lab-based sweat collection patch (large band-aid on the forearm), a Gatorade sweat collection patch on the opposite forearm, and the Hdrop sweat detection device on your left upper arm. the hDrop device is non-FDA approved device because it does not provide a medical diagnosis, but serves as an education and recovery tool. These devices will all be synced with electronic applications (phone apps) to assure data collection. You will then self-insert a rectal thermistor \~15cm past the