Please select the eligibility criteria that correspond to the clinical trial below.
Title: Rapid Acclimatization to Hypoxia at Altitude
Brief Summary: In low oxygen environments, such as altitude, some adults may become ill and suffer from acute mountain sickness. Further, all adults will find that exercising becomes much more difficult when compared with exercise at lower altitudes (e.g. sea-level). The purpose of this investigation is to study the effects of two drugs that may help people adjust to high-altitude quickly, prevent them from becoming ill and improve their exercise performance. The drugs are Methazolamide and Aminophylline.


Options:
A: Inclusion Criteria:

* Permanent residence at low (\<500 m) altitude
* Conventional systolic BP (average of two measurements) 140-159 mmHg or conventional diastolic BP 90-99 mmHg in subjects untreated or after 4 weeks of washout
* Mean daytime systolic BP ≥135 and \<150 mmHg and/or mean daytime diastolic BP ≥85 and \<95 mmHg in subjects untreated or after 4 weeks of washout
* Written informed consent to participate in the study

Exclusion Criteria:

* Conventional systolic BP (average of two measurements) ≥150 mmHg and conventional diastolic BP ≥95 mmHg in treated subjects
* Regular use of two or more antihypertensive drugs (with the exception of subjects on two antihypertensive drugs in low doses)
* Treated antihypertensive subjects in whom withdrawal of treatment is deemed unethical by the investigator (e.g. because of the existence of compelling indications other than hypertension for continuous use of previously used antihypertensive agent)
* Contraindications (including a history of adverse reactions) to angiotensin receptor blockers or calcium antagonists
* History of serious mountain sickness
* Subjects who over 3 months preceding inclusion in the study spent considerable (\> 1 week) amount of time at altitudes above 2500 m.
* Cardiovascular diseases other than hypertension (coronary heart disease, heart failure, atrial fibrillation, valvular or congenital heart disease, cardiomyopathies, cerebrovascular disease, peripheral artery disease, aortic aneurysm)
* Suspected or confirmed secondary hypertension
* Diabetes mellitus
* Serious respiratory disorders
* Other conditions deemed relevant by the investigator (including liver disease, renal disease, thyroid disorders)
* BMI ≥35 kg/m2
* Upper arm circumference \>32 cm
* known severe obstructive sleep apnea (apnea-hypopnea index \> 30 or use of CPAP) or excessive daytime sleepiness (Epworth Sleepiness Scale \> 10)
* Pregnancy
* Premenopausal women not using effective contraceptive methods
* Elevated probability of noncompliance with the study procedures
B: Inclusion Criteria:

* age between 20 and 55 years.
* able to complete the study protocol of 9-day study regimens and mountain climbing twice.
* no prophylactic medication or herb one month before ascent.
* maintaining the same living conditions and habits four months before the first mountain climbing and four months between two mountaineering.

  * living in the same altitude or within a difference of 200 meters.
  * no additional physical training.
  * no plan to gain or loss weight.
  * no altitude exposure above 2500m.

Exclusion Criteria:

* any history of chronic obstructive pulmonary disease, heart failure, cerebral neoplasm, mania, renal or hepatic insufficiency.
* women in pregnancy or intending of pregnancy during the 4-month study period.
C: Inclusion Criteria:

* Member of the Italian High Altitude Research Expeditions

Exclusion Criteria:

* Are under the age of 18years;
* sulfonamide allergy
* Liver or kidney disfunction
* Have any other uncontrolled medical condition
* Or are unable to give consent.
D: Inclusion Criteria:

* normotensive (i.e. \<140/90 mmHg)

Exclusion Criteria:

* Pregnancy
* nursing mother
* current tobacco use or regular use within the previous two years
* use of prescription medication other than birth control
* asthma or any other type of lung/respiratory dysfunction
* resting oxygen saturation \<95%
* unwillingness to abstain from exercise for 48 hours prior to laboratory testing
* use of anticoagulant therapy or have a known or suspected bleeding disorder
* identification of contraindication during screening (i.e. positive stress test)
* any history of mountain sickness (altitude sickness)
* any history of allergic reaction, hypersensitivity or idiosyncratic reaction to any of the products administered during the study, including allergy to any sulfa or sulfonamide derivatives
* history of clinically significant illness within 4 weeks prior to Day 1
* Subjects who have made any significant donation (including plasma) or have had a significant loss of blood within 30 days prior to visit 1
* receipt of a transfusion or any blood products within 30 days prior to visit 1.

Answer: D