The number of persons with hypertension is increasing and with it the number of related cardiovascular events and related functional or cognitive declines. While studies have suggested that physical activity, in particular, high-intensity interval training (HIIT), could be as efficient as the commonly used antihypertensive medications, no studies have actually compared their effects in the same population. This protocol will determine if HIIT is at least as efficient as hydrochlorothiazide in order to lower 24h-ambulatory blood pressure (BP) in prehypertensive older adults.

Inclusion Criteria:

1. Age at consent ≥ 60 years;
2. Systolic Blood pressure measured through BPtru™ between SBP ≥ 120 mmHg and < 140 and or DBP ≥ 80 mmHg
3. Being able to sign the informed consent form

Exclusion Criteria:

1. Considered "highly active" according to the International Physical Activity Questionnaire
2. Practicing more than 20 min per week of High-Intensity Interval Training
3. Use of antihypertensive medication
4. Contraindication for the practice of intense physical activity
5. Functional limitations related to the exercise test and to intensive training
6. Cardiovascular pathology
7. Atrial fibrillation
8. Psychiatric or neurological disorder
9. Renal failure
10. MMSE score < 26
11. Persons benefiting of enhanced protection: persons deprived of their liberty by a judicial or administrative decision, persons staying in a health or social institution, adults under legal protection and patients in emergency situations.
12. Diabetes