Taurine and Nitrate Supplementation on Thermoregulatory in T2DM

Whole body sweat rate

WBSR will be measured by taking a nude body mass (kg). Participants will be shown to a private changing facility in which the scales (Industrial Electronic Weight Indicator, Model 10, Ohaus Corporation, Parsippany, NJ, US) are located, with the screen for the value reading located outside to ensure privacy of the participant. The pre-mass measure will occur during every experimental visit, before the instrumentation section of the visit. Towel dried nude body mass will then be recorded once de-instrumentation has occurred. The equation below will be used to calculate WBSR. WBSR (L/h) equation: (Pre body mass (kg) - Post body mass (kg)) + Fluid intake (L) - Urine output (L) Duration of test (hrs)

Local sweat rate:

The Q-sweat (Qsweat Quantitative Sweat Measurement System, WR Medical Electronics Co., Minnesota, USA) will be used to understand LSR during the heat event. Participants will be instrumented with the ventilated sweat capsule and placed on the upper back (mid scapula) and onto the mid anterior forearm. Additionally, measuring the forearm may provide insight into regional differences and any autonomic dysfunction in sudomotor response. This will be measured continuously throughout the investigation through the software TestWorks (TestWorks software, WR Medical Electronics Co., Maplewood, MN, USA). Live data will be gathered during the trials and subsequent data will be processed into one-minute averages across each trial.

Rectal temperature Trec

Trec will be measured continuously (1s intervals) throughout each trial. This will be measured via a rectal thermistor (PROACT Temperature Probes, Northamptonshire, United Kingdom).

Skin temperature: Tsk

Tsk will be assessed using four skin thermistors (Grant Instruments, Cambridge, UK), at the sites on the right side of the body at the locations, pectoralis major, biceps brachii, mid-thigh and the gastrocnemius. Thermistors will be placed during the instrumentation part at the start of the protocol and will remain on location until the session has concluded. Data will be recorded throughout the whole duration of the experimental protocol. These will be held in place by a Tegaderm™ dressing (Tegaderm™ Dressings, 3M, St. Paul, Minnesota, USA) with additional tape anchoring them to the skin to avoid movement. Minute averages will be recorded for the duration of the protocol and plotted to understand the change in temperature throughout each trial, to provide information on the specific temperatures that have been identified. Mean skin temperature = (0.3\*Tpectorlis) + (0.3\*Tbicep) + (0.2\*Tthigh) + (0.2\*Tcalf) \*expressed as an indication of multiplication.

Mean Body temperature

Mean body temperature will be measured to provide an overall measure of heat gain for the individual through the combination of Trec and Tsk. The weighting of the different measures of temperature is determined by the ambient temperature of the surrounding, as the protocol will be of a hot environment the below equation was chosen over other weightings, which is as below in Equation two (Burton et al., 2025). This will be measured at all time points that Trec and Tsk are taken in conjunction with each other. This will be measured as absolute values in degrees Celsius, for all time points and also be expressed as a delta change from the baseline temperature or between other specific time points chosen, to provide an understanding of the rate of change. Mean body temperature = Tˉsk=0.3(Tchest+Tarm)+0.2(Tthigh+Tcalf)