Sweat Rate Measurement
Sweat collection can be used to determine the sweat rate for a particular part of the body. If you wish to measure total body sweat rate, you can use the body weight method.
- purpose: to use sweat patches applied to the skin to collect a sample of sweat for analysis.
- equipment required: sweat patches, razor, alcohol wipes, pipette, gloves, storage container, small scales, sweat analyzer (or external laboratory).
- procedure: The sweat collection patches should be prepared of standard known size (the area of collection is required for rate calculations). A popular method is to use paraffin film to cut out the desired shape which is stuck onto a rectangle of clear tape. See the diagram for an example. There are many possible skin sites to use for sweat collection. The site used may depend on the purposes of testing. Commonly used are the upper back, chest, forearm, thigh and forehead. If standard sites are used, they need to be measured up and marked for correct placement. Prepare the skin by shaving any hair and clean with alcohol wipes and allow to dry. Another method is to wash the area with de-ionized water. Place the sweat patch on the desired site. After a pre-determined exercise time, the top of the patch is opened and a pipette is used to siphon off a sample of the sweat. The sweat is then transferred to a contained and weighed.
- results: sweat rate can be calculated by dividing the volume of sweat collected by the skin area. If using a patch like the example illustrated, the area of skin = ( a x b ) + (c x d). The collected sweat can also be sent for analysis to determine electrolyte composition. Alternatively you can use sweat patches made to do the same job.
- reliability: If the subject is to be retested, or athletes are being compared, accurate placement of the patches is very important for reliability. It is also important to standardize the testing conditions, so that the exercise intensity, duration, clothing, and environment are the same.
Related Pages
- hydration for sport: a collection of articles
- measuring dehydration
- other methods: urine color measurement, sweat analysis, urine specific gravity, body weight changes.
