A single-centered randomized doubled blinded placebo-controlled cross-over trial comparing two the effect of two carbonic anhydrase inhibitors on exercise performance in acute hypoxia. Participants will be young (under 40 years of age), healthy males and females who are regularly physically active.

Inclusion Criteria:

• Consent provided
• Between ages of 18-40 years old
• In good general health as evidences by medical history
• Perform at least 150 mins of aerobic exercise per week, and engage in physical activity >2 days a week
• Completed in an endurance event in the last 12 months
• Ability to take oral medication, and be willing to adhere to the drug regimen
• Be willing to have blood samples taken

Exclusion Criteria:

• Weigh 49kg or less, or are Obese (BMI >30 kg/m2)

• Presence of chronic health condition (s), being investigated and/or taking prescription medications for the following disorders:

  1. Cardiovascular - e.g., hypertension
  2. Metabolic - e.g., type 1 or 2 diabetes
  3. Respiratory - e.g., chronic obstructive pulmonary disease, asthma
  4. Digestive - e.g., ulcerative colitis
  5. Arthritis
  6. Cancer

• Presence of any disorder or condition listed in the health screening questionnaire (see section 12.1)

• Current use of Lonafarnib, Methenamine, Topamax, or steroids/corticosteroids

• Known allergic reactions/hypersensitivity to carbonic anhydrase inhibitors or sulfonamides

• Presence of bleeding or clotting disorders

• Current smoker or cannabis user

• Pregnant, suspect to be pregnant, currently planning a pregnancy, or nursing

• Any condition or diagnosis, that could in the opinion of the Principal Investigator or delegate interfere with the participant's ability to comply with study instructions, might confound the interpretation of the study results, or put the participant at risk