Beware of trying to lose weight while running: hours and hours of treadmill or similar cardio (with the elliptical, with the exercise bike, with the stepper), and hours and hours of running could cause you overtraining, slow metabolism and even hypothyroidism. This is what John Kiefer , doctor of physics and nutrition expert, as well as certified personal trainer states, who in an article entitled ” Why women shouldn’t run” explains how attempts to lose weight by running often lead to obtaining the opposite of what one expects, exposing a number of recent studies.

But why is it aimed at women and not men? Because in gyms, the people who spend hours doing cardio instead of trying to train with weights are usually women, or mostly women.
They are the ones you see sweating every day, going to the gym every day, running for at least an hour.

What are the disadvantages of this behavior?
1) Continuous cardio does not promote the loss of body fat, on the contrary, it can cause us to lose muscle mass: continuous training at over 65% of the maximum heart rate leads the body to maintain fat reserves, saving them to attack the muscles.
2) Cardio overtraining can cause hypothyroidism according to recent studies and a resistance to leptin, altering our sense of satiety and therefore of hunger.
3) The body tends to adapt to cardio work, lowering the metabolism to the detriment of natural thermogenic processes that keep us active and healthy and make us burn more thanks to involuntary movements during the day (NEAT) and food.

This is not about proper cardio or cycling periods of workouts that include some cardio , but that continuous cardio-based gym workout that people sustain for years to lose weight.