Cardio

Carry and use more oxygen

During exercise, the heart speeds up to supply more blood to the muscles and breathing increases. Repeated training leads to adaptations: the heart can send more blood with each beat, while the muscles improve their ability to use oxygen. An effort that left you very out of breath can then become easier to sustain.

In muscles, adaptations particularly concern the mitochondria, which participate in energy production, and the network of small vessels. VO₂ max describes the maximum amount of oxygen that the body can use during intense exercise. It's a benchmark of cardiovascular fitness, but you don't need to measure it to feel progress in your usual activities.

Expend energy and modify the silhouette

Cardio increases energy expenditure and can reduce body fat and waist size. A meta-analysis of trials published in 2024 observes these benefits in overweight or obese adults, with an important role of weekly volume. The individual result nevertheless depends on the diet, the initial level and the regularity; the expense of a session alone does not guarantee weight loss.

Skin circulation and complexion after exercise

During a session, more blood can circulate in the skin to dissipate heat: the face can then appear more colored. This immediate effect is temporary. In the longer term, a meta-analysis of seven trials observed an improvement in the reactivity of small cutaneous vessels with aerobic training, mainly studied in previously inactive or older adults.

This better vascular response is interesting for the functioning of the skin, but the trials did not directly evaluate a more even or luminous complexion. It is therefore necessary to distinguish between the measured circulatory function and the aesthetic result. Cardio can promote a beneficial physiological environment for the skin; a permanent effect on its color is not automatically deduced from circulation.

A complexion perceived as healthier

A study published in 2020 provides a result more directly linked to appearance. In young adults, better cardiovascular condition was associated with a yellow-golden coloring of the complexion, compatible with carotenoid pigments. The link persisted after taking into account several factors, including reported fruit and vegetable intake and body fat. A follow-up over eight weeks also found an association between progression of physical condition and evolution of this coloring.

In a perception experiment, faces whose color had been modified to reproduce this association were judged to be healthier. This supports the idea of ​​a possible benefit on the complexion, distinct from a simple blush after exercise. However, the study did not randomize a cardio program: it shows associations and visual perception, without demonstrating that a specific routine will give this result to everyone.

Encouraging results on elasticity

A sixteen-week trial published in 2023 compared aerobic and strength training in sedentary middle-aged Japanese women, with 56 participants analyzed. Both groups improved skin elasticity and dermis structure measures at the cheek level. The increase in the thickness of the dermis mainly concerned bodybuilding: it should not be attributed in the same way to cardio.

These measurements show that the potential benefit of exercise for the skin is not limited to the complexion immediately after a session. The trial remains limited in size and compared two training sessions without an inactive group; it therefore does not make it possible to quantify visible rejuvenation or to guarantee the same results in young men. The signal is nevertheless positive for integrating cardio into an overall approach to improving appearance.

Complete bodybuilding

The two training can coexist: endurance improves the ability to sustain an effort, while bodybuilding mainly develops strength and muscle mass. Research reviews do not show a systematic loss of muscle gains when combining the two. However, fatigue still needs to be managed, particularly if the sessions are long or very intense.

For a person who is mainly looking to develop their physique, maintaining good performance in bodybuilding is a useful benchmark. If cardio constantly leaves you tired and degrades your sessions, adjust its volume or placement. A complementary program should allow you to progress in both areas, with sufficient nutrition and recovery.

Benefits beyond the mirror

Regular physical activity also benefits cardiovascular health, sleep and mental health. These effects matter even if the weight changes little. Cardio thus helps to build a more complete physical condition: being able to move for a long time, better tolerate efforts and maintain a pleasant sporting activity represents a result in its own right.