
10/14/2025
Scientific research on the limits of human endurance confirms that pregnancy is one of the most demanding metabolic feats possible, as the sustained energy required to grow a baby over nine months forces the mother's body to operate at an elevated rate of approximately 2.2 times her resting metabolic rate—a level nearly equivalent to the physical ceiling sustained by elite endurance athletes, such as those running a marathon per day for several weeks. This comparison underscores the sheer, continuous intensity of pregnancy, highlighting it as the longest and one of the highest energy-expenditure events the human body can endure.