Women as Endurance Athletes: What You Need to Know

Women are very quickly becoming the fastest growing segment of endurance athletes.   Studies suggest that women utilize less glycogen and more fat than men in long, lower-intensity exercise. This makes female athletes particularly well suited for, and may potentially provide an advantage over men in endurance events. Training and competition in endurance events have obvious health benefits, but there are some short-term and long-term negative health consequences, particularly in women, to avoid.

Females clearly have different nutrient requirements than males. Many of these differences are simply based on body size, but others are due to physiological differences.  It is by understanding these physiological differences, that the female endurance athlete can reduce her risk of some immediate and long-term health problems.

Menstrual cycle dysfunction and bone loss

Female endurance athletes who train intensely are at risk for menstrual cycle dysfunction such as amenorrhea (complete lack of menses) or oligomenorrhea (decrease frequency of menses).  This risk likely has to do with a chronic under consumption of calories.  Insufficient caloric intake leads to malnutrition, which increases the likelihood of menstrual dysfunction.  Menstrual dysfunction then leads to hormonal imbalances, which cause a reduction in bone density.  This reduction in bone density in the short-term places the female endurance athlete at increased risk of injuries such as stress fractures.  In the long-term and much, more insidiously these hormonal imbalances can lead to osteoporosis, which is a very common cause of disability and reduced quality of life in older women.  Ensuring that you are eating enough calories and getting enough calcium in your diet may help reduce the risk of menstrual dysfunction and the associated reduction in bone density.


Iron is an integral component of red blood cells (RBCs) and without enough iron, anemia (decreased RBC count) develops which can lead to a reduction in exercise capacity, impaired performance, tiredness, cramping and headaches. In both men and women, iron is lost in sweat, feces, urine, and heel strike hemolysis (the destruction of RBCs caused when the heel hits the ground with force, i.e. running). Due to the added blood loss that women experience with menstruation, iron deficiency is another common problem found in female athletes.

The best way to prevent iron deficiency anemia is to eat a diet that is well fortified in iron and secondarily by wearing well cushioned shoes and running on softer surfaces (to reduced heel strike hemolysis).


  • Eat!  Make sure you are taking in enough calories to meet your energy demands.  If you are unsure how, than is consider talking to a trained sports nutritionist.  You may even consider undergoing testing.  Using oxygen consumption analysis you can find out your basal metabolic rate (how many calories you burn up in a day just being alive) and the amount of calories burned at varying levels of exercise.  You can then use this information to make sure that your energy consumption is always greater than your energy expenditure.  If you do experience menstrual cycle dysfunction, talk to your doctor.
  • Make sure you are getting at least the recommended daily allowance (RDA) of calcium and iron.  Depending on your level of activity, you may need even more than the RDA.
  • Get your blood checked at least yearly to assess calcium levels, make sure that your RBC count is normal and that your iron levels and stores are adequate.
  • Consider bone density testing every few years to make sure your bone density levels are appropriate for your age.
  • Defy expectations, shatter all stereotypes and let your competitive side shine though.


-Dr Sal (The Raw Cardiologist)