Night sweats reveal the severity of sleep apnea


University of Córdoba
Changes in sweat metabolism can help in the diagnosis the severity of sleep apnea. 

Researchers at the University of Córdoba and IMIBIC have joined forces in a groundbreaking initiative, utilizing changes in sweat metabolism as a novel method for diagnosing the severity of sleep apnea.

Sleep apnea, characterized by interruptions in breathing during sleep, is derived from the Greek word "apnea," meaning the "absence of breathing." Patients with this condition often experience sensations of breathlessness, fatigue, and drowsiness.

Recognizing the potential links between sleep apnea and cardiovascular disorders, the collaborative effort aims to establish an effective means of diagnosing the severity of the condition.

By tapping into changes in sweat metabolism, the researchers hope to provide a new and reliable tool for assessing the impact and seriousness of sleep apnea. This innovative approach could offer valuable insights for both patients and healthcare professionals, leading to more targeted and efficient interventions.
Researchers from the University of Córdoba and the Maimonides Institute for Biomedical Research in Córdoba (IMIBIC) are making strides in the diagnosis of sleep apnea by examining alterations in the metabolism of individuals affected by the condition.

Traditionally, assessments of these metabolic changes have been conducted using blood or urine samples. However, seeking a more accessible and less invasive alternative, a team from the Department of Analytical Chemistry at the University of Córdoba, including Laura Castillo, Mónica Calderón, Feliciano Priego, and Bernabé Jurado, has pioneered the examination of sweat samples for this purpose.

In a groundbreaking development, the researchers have, for the first time, validated the potential of sweat samples in determining the severity of sleep apnea. Lead author Laura Castillo highlights the benefits of this approach, stating, "By analyzing sweat metabolome and its alterations, mainly at night, we were able to see what stage of the disease the patients were in."

The use of sweat offers distinct advantages over other sample types. Castillo emphasizes its non-invasive nature and cleanliness, stating, "it is a non-invasive and clean sample since, unlike the case with blood, we don't have to remove proteins, and it's much easier to analyze and detect metabolites." This innovative method could revolutionize the diagnosis and monitoring of sleep apnea, providing a simpler and more patient-friendly means of assessing the severity of the condition.
In this research, sweat samples collected before and after sleep were scrutinized from individuals at various stages of sleep apnea, as well as from a control group without the condition.

Employing gas chromatography coupled with high-resolution mass spectrometry, the team identified and studied 78 metabolites in these samples, primarily linked to energy production and oxidative stress.

Lead author Laura Castillo explains, "We could see how the sweat metabolism itself indicates those alterations during sleep as a result of which the person's energy production worsens and their oxidative stress increases."

This insightful approach enables a personalized monitoring of the disease by analyzing the sweat excreted during sleep, allowing for tracking its progression and monitoring potential effects, such as cardiovascular problems.

Moreover, the metabolomic profile distinguished between individuals with the disease and those in the control group who did not have it. This promising development could pave the way for more accurate and efficient identification of sleep apnea, offering a valuable tool for both diagnosis and ongoing assessment.

An index to learn more about the disease

Apart from establishing sweat as a reliable indicator for gauging the stage of sleep apnea, this research emphasizes the significance of incorporating the oxygen desaturation index into the diagnostic process.

Currently, the diagnosis of sleep apnea relies on the Apnea-Hypopnea Index (AHI), which quantifies the episodes of breathlessness per hour (for instance, the condition is deemed severe with 30 or more episodes per hour). However, the research team notes that the AHI "does not provide all the information about the disease or the patient's situation at a given time" as it tallies the number of events but not their severity.

In their study, the researchers underscore the importance of also considering the oxygen desaturation index. This index measures the seriousness of episodes by tracking events where oxygen saturation has dropped by more than 3%. Confirming a linear relationship between this index and the AHI, its validity is established. The oxygen desaturation index complements the AHI by not only providing event data but also assessing severity through oxygen saturation loss, enhancing the diagnostic accuracy of sleep apnea evaluations.