Page 9 - Read Online

Brasier et al. Soft Sci 2024;4:6 https://dx.doi.org/10.20517/ss.2023.39 Page 7 of 10

Table 2. Summary of the terminology of clinical sweat assessment
Umbrella term Specification Description
Sweat rate Local Sweat collected from a specific body surface over a specified time
-1 -2
(indicated in g·h ·m )
Whole body sweat loss Total amount of water lost due to sweating over a specified time
Causes of sweat rate Iatrogenic Sweat rate impacted through medical treatment or intervention
changes
Non-iatrogenic Changes of the sweat rate that are not directly caused by medical treatment
Amount of sweat Hyperhidrosis Increased above the physiological need regarding the maintenance of the
thermoregulation of the body
Hypohidrosis Decreased under the physiological need regarding the maintenance of the
thermoregulation of the body
Anhidrosis No sweating
Changes in the amount of Focal Specific locus on the body surface is affected
sweat rate
Generalized The whole-body surface is presumed to be affected
Primary Caused within the functional chain of the sweat gland
Secondary Due to external variables of the chain of the sweat gland

changes affecting the sweat gland function (e.g., in cystic fibrosis); (viii) brain infarction; or (ix)
pharmacological treatments with amiodarone or hormone substitution, may lead to hyperhidrosis.

Hypohydrosis
Hypohydrosis can be categorized into exogenous, dermatological, and neurological causes . Systemic
[59]
neurohormonal inhibition of sweating or damage to skin and sweat glands can result from exogenous
reasons. Congenital disorders lead to dermatological disorders, and neurological pathologies can be caused
by autonomous dysfunction.

While hyperhidrosis can be an indicator of serious health deterioration, hypohydrosis is less often clinically
significant. However, hypohydrosis can be an indicator of peripheral polyneuropathy such as in Diabetes
Mellitus. Hypohydrosis can be assessed using one of the few established clinical sweat tests, namely the
thermoregulatory sweat test (TST) . For the TST, an indicator powder that changes color upon contact
[60]
with sweat is applied to the skin. The person undergoing examination is subsequently exposed to
environmental heat that usually leads to increased sweating. This process helps identify hypohydrotic skin
areas.

CONCLUSION
Sweating is a common symptom in clinical medicine beyond sports science. Up to date, the absolute
quantification of the sweat rate is challenging as the gold standard analysis by gravimetrical analysis is
neither continuous nor feasible outside of a lab setting. These barriers are the main factors why sweat
analysis has not been implemented in clinical medicine yet. Novel wearable sweat analyzing biosensors
enable us to easily and continuously monitor the sweat rate independently of specialized laboratories. With
the emergence of these novel biosensing devices, the sweat rate is accessible for structured clinical
investigation and can serve as a novel digital biomarker. Importantly, cyber security, bioethical, and policy
considerations need to be addressed for successful clinical implementation [61,62] . Clinical investigations are
needed to demonstrate the additional clinical value of wearable sweat rate analysis for all stakeholders in
healthcare.