Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by the occurrence of abnormally frequent episodes of interrupted ventilation (apnea) or significant reduction of ventilation (hypopnea) during sleep. It is linked to a repeated collapse of the upper airways during sleep.

Episodes of apnea and hypopnea cause hypoxemia and micro-awakenings with a well-established impact on quality of life and daily activities. Physiologically, OSAHS can be aggravated when moving from a standing to a supine position through fluid shift from the lower limbs to the upper body, thereby modifying the opening of the upper airways. A decrease of the water balance by bilateral diurnal compression of the lower limbs (during daytime in standing position) may limit this nocturnal fluid shift (at night in supine position) and thus reduce the severity of OSAHS.

Two comparative clinical trials [Redolfi 2011; White 2015] have shown a clinically modest reduction of sleep apnea (-36% and -27%, respectively), which was however statistically significant versus untreated control group (p = 0.002 and p = 0.04, respectively), when elastic compression medical devices of 20 to 30 mmHg were worn during the daytime. The hypothesis of fluid shift influence on OSAHS has been tested [Berg 1993; Redolfi 2011; White 2015], but the decrease of the water balance when the device is used remains to be quantified.

The CVE101-15 exploratory clinical investigation sponsored by Laboratoires Innothera performed on healthy volunteers confirmed the hypothesis of a diuretic effect of elastic compression stockings applying a pressure of 33 mmHg at the ankle, worn for 13-14 hours during the daytime for 3 days, with a good safety profile of this device. Moreover, it enabled the identification of reliable parameters and the endpoints to be used to demonstrate a diuretic effect.

Based on this information, there may be a real interest in conducting further investigations about the evolution of water balance beyond a 3-day period of elastic compression use in the daytime.

Hence, the main objective of this clinical investigation is to compare precisely, under standardized test conditions, water balance changes in healthy subjects over 5 days with or without daytime use of the investigational medical device (IMD), an elastic compression device prototype specially designed for this study.

Inclusion Criteria:

1. Male subject aged 40 years old or more.
2. Subject with a body mass index (BMI) between 18.5 and 30 kg/m².
3. Healthy subject, registered in the French biomedical research volunteer national file.
4. Subject for whom both lower limb measurements correspond to the size grid of the IMD used.
5. Subject agreeing to abstain from alcohol intake from 48 hours before P1D-2, during all hospitalization periods and during the outpatient period.
6. Subject accepting to proceed with a COVID-19 test at the time of each inpatient period, and for whom the result is negative
7. Subject accepting to protect himself in an appropriate way to avoid COVID-19 infection during the outpatient period.
8. Subject practicing under 5 hours of intense physical activity per week, on average, in the 4 weeks preceding the screening visit (e.g. no marathon training or military training).
9. Subject agreeing to abstain from any strenuous activity, especially sports, from the screening visit to the end of clinical investigation (including during the outpatient period).
10. Subject accepting the constraints of the clinical investigation.
11. Subject being available for the duration of the clinical investigation.
12. Subject who has signed the informed consent form (ICF) after being adequately informed and receiving the information sheet.
13. Subject affiliated with the French social security system or receiving benefits of that type.

Exclusion Criteria (non-inclusion criteria):

1. Subject who is a smoker or a former smoker who stopped smoking less than 6 months ago.
2. Subject following a salt-free diet.
3. Subject following or planning to follow either a slimming diet or any specific diet that could not be followed during hospitalization.
4. Subject having a temperature > 38.0°C at screening or in the morning of D-2 and D1 of the first period (P1).
5. Subject having, upon clinical examination, an abnormal systolic blood pressure (SBP), diastolic blood pressure (DBP) or heart rate (HR) judged clinically significant by the Investigator.
6. Subject having an intestinal transit disorder that disrupts hydroelectric balance.
7. Alcohol-dependent subject or subject with a positive alcohol breath test.
8. Subject having a localized or general edema (a simple evening edema of the legs or ankles is accepted for inclusion).
9. Subject suffering from insulin-dependent or uncontrolled diabetes (controlled diabetes is accepted).
10. Subject with a serious, stabilized, or progressive illness (as judged by the Investigator).
11. Subject with hypertension or heart failure.
12. Subject with known renal function disorders.
13. Subject with known liver failure.
14. Subject with venous insufficiency of clinical class C3, C4, C5 or C6 according to the Clinical / Etiological / Anatomical / Pathophysiological (CEAP) classification.
15. Subject having a medical background of deep and superficial vein thrombosis.
16. Subject following long-term therapy with diuretics, nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, nutritional supplements or opiates.
17. Subject having, upon questioning or clinical examination, advanced peripheral neuropathy, skin infections, eczematous dermatitis, or weeping skin disorder of the legs.
18. Subject with a medical contraindication to compression therapy according to the interview or clinical examination: phlegmatia coerulea dolens, septic thrombosis, intolerance to the IMD, allergic reaction to any component, arteritis obliterans of lower limbs, advanced diabetic microangiopathy.
19. Subject with active implants, such as a pacemaker or artificial heart type, and non-active implants, for example a hip prosthesis (dental implants are authorized).
20. Subject who is participating in another clinical trial or who is in the exclusion period from a previous study/clinical investigation.
21. Person deprived of freedom by judicial or administrative decision, or a person hospitalized without his consent.
22. Subject of legal age who is protected by law or under guardianship.
23. Subject with a current mental or psychiatric disorder or a history of mental or psychiatric disorder, or any other factor limiting the collection of informed consent.
24. Person who works for the CRO or for Laboratoires Innothera, or has a dependent relationship with these entities.