Researchers will compare results reported by STW to those of SDW group to see if significative differences are detectable. conditions: Long-COVID conditions: Post COVID-19 Condition conditions: Chronic COVID-19 Syndrome conditions: Post Acute Sequelae of COVID-19 studyType: INTERVENTIONAL phases: NA allocation: RANDOMIZED interventionModel: PARALLEL interventionModelDescription: The study is a double-blind, interventional, randomized case-control, pilot trial assessing the efficacy of sulfureous thermal water (STW) inhalations in patients diagnosed with long-COVID. The eligible subjects were randomized in a 1:1 ratio to either: active (STW) or placebo (SDW) group for the inhalation therapy and tested at 3 timepoints: Visit 1 (prior treatment), Visit 2 (just after treatment) , Visit 3 (3 months after treatment). primaryPurpose: TREATMENT masking: TRIPLE maskingDescription: Neither the participants nor any of the medical researchers or laboratory staff involved in the screening, enrolment, clinical evaluation, monitoring, and laboratory as well as statistics of the participant's analyses were aware of the study intervention received (STW vs SDW). A randomization list (1:1 active vs placebo) was created prior to recruiting. The inhalation assistant randomized the participant according to the list and administered the intervention. Therefore, the inhalation assistant was unblinded to the treatment assigned but blinded to the medical condition of the participants. whoMasked: PARTICIPANT whoMasked: INVESTIGATOR whoMasked: OUTCOMES_ASSESSOR count: 30 type: ACTUAL name: Inhalation of Sulfurous Thermal Water name: Inhalation of Sterile Distilled non-pyrogenic Water measure: To determine whether Sulfurous Thermal water (STW) inhalations may have effects on post covid-pulmonary sequelae assessing changes in pulmonar functionality through spirometric parameters. measure: To determine whether Sulfurous Thermal water (STW) inhalations may have effects on post covid-pulmonary sequelae assessing changes in pulmonar functionality through spirometric parameters. measure: To determine whether Sulfurous Thermal water (STW) inhalations may have effects on post covid-pulmonary sequelae assessing changes in pulmonar functionality through spirometric parameters measure: To determine whether Sulfurous Thermal water (STW) inhalations can improve the cardiopulmonary response to physical exertion measured as SpO2, Heart rate, Borg score and traversed meters in patients affected by long COVID measure: To determine whether Sulfurous Thermal water (STW) inhalations can improve the cardiopulmonary response to physical exertion measured as SpO2, Heart rate, Borg score and traversed meters in patients affected by long COVID measure: To determine whether Sulfurous Thermal water (STW) inhalations can improve the cardiopulmonary response to physical exertion measured as SpO2, Heart rate, Borg score and traversed meters in patients affected by long COVID measure: To assess if H2S present in STW can interfere with concentration of inflammatory markers ( as IL1B, IL-6, ACE, S100B, GSS, Hs-CRP) typically alterated in long covid patients. measure: To assess if H2S present in STW can interfere with concentration of inflammatory markers ( as IL1B, IL-6, ACE, S100B, GSS, Hs-CRP) typically alterated in long covid patients. measure: To assess if H2S present in STW can interfere with concentration of inflammatory markers ( as IL1B, IL-6, ACE, S100B, GSS, Hs-CRP) typically alterated in long covid patients. measure: to assess whether thermal water inhalation with sulfurous water may determine qualitative and quantitative changes of the nasal microbiome by assessing alpha and beta diversity after nasal sample collection measure: to assess whether thermal water inhalation with sulfurous water may determine qualitative and quantitative changes of the nasal microbiome by assessing alpha and beta diversity after nasal sample collection measure: to assess whether thermal water inhalation with sulfurous water may determine qualitative and quantitative changes of the nasal microbiome by assessing alpha and beta diversity after nasal sample collection measure: to assess whether thermal water inhalation determine changes in the perceived impact of respiratory related impairment on the quality of life (Qol) through a validate Saint George respiratory questionnaire measure: to assess whether thermal water inhalation determine changes in the perceived impact of respiratory related impairment on the quality of life (Qol) through a validate Saint George respiratory questionnaire sex: ALL minimumAge: 18 Years maximumAge: 75 Years stdAges: ADULT stdAges: OLDER_ADULT facility: Acque Albule, Terme di Roma city: Tivoli state: Rome zip: 00019 country: Italy lat: 41.95952 lon: 12.8016 hasResults: False