Actress Kim Hye-soo (55) recently shared a glimpse into her dedicated fitness routine.
Kim Hye-soo posted a video on social media showing her happily pedaling an underwater bike in a swimming pool, leaning into the resistance of the water current. Wearing a full-body swimsuit, she drew widespread admiration for her firm, lean physique. With remarkably little excess body fat, her appearance makes it difficult to believe she is in her mid-50s.
Cardiovascular and strength training with minimal joint stress
The workout Kim Hye-soo selected—underwater biking—involves pedaling a stationary bicycle submerged in water. This exercise effectively combines cardiovascular and strength training by utilizing both buoyancy and resistance. While buoyancy reduces the weight-bearing load on the body to minimize joint impact, the density of the water increases muscle activation and calorie expenditure.
For middle-aged women, muscle loss and joint degeneration often occur simultaneously. This makes water-based exercise particularly beneficial, as it allows for high activity levels with a significantly lower risk of injury. Furthermore, water pressure can support peripheral circulation, helping to reduce swelling and promote healthy blood flow.
Optimizing intensity through water temperature and depth
Despite the benefits, maintaining proper form is essential, as the buoyant environment can cause the pelvis to sway or the lower back to arch excessively. To ensure a safe workout, it is important to engage the core and glutes while keeping the upper body stable.
Environmental factors also play a role. If the water temperature is too low, the resulting drop in body temperature can stiffen muscles and increase fatigue; therefore, sessions should be held in temperature-controlled pools. A water depth reaching the solar plexus is generally ideal. If the water is too deep, the intended exercise intensity may actually decrease.
Precautions for those with underlying conditions
Individuals with high blood pressure or cardiovascular disease should exercise caution, as fluctuations in water pressure and temperature can place additional strain on the heart. It is advisable for these individuals to begin at a low intensity, carefully monitoring their body’s response before gradually increasing the duration and difficulty of the workout.
