Aging is linked to a higher risk of cardiovascular disease. Physical exercise is recognized as an excellent strategy to prevent cardiovascular diseases and cognitive aspects, generating healthier elderly people. The beneficial effects of physical training seem to be greater when performed:

• In hypoxic conditions (i.e. when the amount of oxygen in the air is decreased as at altitude).
• With intermittent blood flow restriction (by inflating pneumatic cuffs around the thighs to a pressure that restricts blood flow). This equipment is harmless.
• With eccentric training (resisting against the movement of the pedal of a bicycle rather than pushing it).

The purpose of this study is then to evaluate whether moderate intensity intermittent training can induce similar or greater effects on cardiovascular health when combined with intermittent hypoxia, intermittent blood flow restriction or eccentric training.

Aging is associated with a higher risk of cardiovascular disease due mainly to high blood pressure. Physical exercise is recognized as an excellent non-pharmacological strategy to prevent cardiovascular disease and cognitive aspects, thus generating healthier elderly people.

• Interestingly, living at altitude seems to reduce some cardiovascular risks. In addition, the beneficial effects of physical training seem to be greater when performed under hypoxic conditions (i.e. when the amount of oxygen in the air is decreased as at altitude).
• Another interesting strategy for the elderly is intermittent blood flow restriction. This involves inflating pneumatic cuffs around the limb(s) to a pressure that blocks or restricts blood flow to the affected muscles, alternating with rest phases. It has been found that endurance training, combined with blood flow restriction, promotes the growth of new blood vessels, which could be particularly important for the prevention of cardiovascular disease in the elderly, which is unfortunately common.
• Eccentric training is currently emerging as a promising training strategy for the elderly. It consists of resisting the movement of the pedal of a bicycle rather than pushing it. It requires less energy effort than traditional exercise with the same workload. Eccentric training has been shown to improve older adults' body composition and muscle strength, thereby improving exercise capacity and quality of life.

These training strategies may be of interest for cardiovascular health in older adults. However, there are few data on their combined effects with exercise in the elderly and there is no consensus to favor one method over another.

The objective of this study is then to evaluate whether moderate-intensity intermittent training can induce similar or superior effects on health indicators when combined with intermittent hypoxia, partial vascular occlusion, or eccentric training.

Inclusion Criteria:

1. to be aged between 65 and 75 years old
2. not involved in regular physical activities for at least 6 months (i.e., doing no physical exercise over twice per week);
3. free of injuries as well as cardiovascular and respiratory disorders or central nervous system disease or receiving β-blocker medication;
4. not using dietary supplements, smoking or drugs which interfere with the measurements;
5. not using creatine supplementation, anabolic steroids, drugs, or medication with potential effects on physical performance;
6. to have body index mass between 20 and 30 kg/m²;
7. not to live above 800m of altitude;
8. to be vaccinated against COVID-19 and to have no symptoms (fever, cough, fatigue, loss of smell or taste);
9. able to complete all sessions;
10. able to give consent.

The active-control group will receives a comparable standard treatment to the three other groups: Moderate Intensity Interval Training on a ergocycle without any additional feature.