A Healthy Body Fat Percentage For Runners

To run your best, it is important to maintain a healthy body fat level. Too little body fat can hinder performance and lead to injury and illness. Maximizing performance also requires reaching the best strength-to-weight ratio possible. That is achieved by minimizing body fat. To run your best while staying healthy and safe, try to reach and maintain a healthy body fat percentage, because lighter is not always better.

Women's General Body Fat Categories

The American Council on Exercise (ACE) divides body fat percentage into five different categories. They are essential, athletes, fitness, acceptable and obese. Essential body fat ranges from 10 to 14 percent. The athlete category is 14 to 20 percent, while the fitness group is 21 to 24 percent. Any women runner with a body fat percentage between 14 and 24 percent would be considered healthy based on these categories. However, those in the fitness and higher end of the athlete category could possibly improve performance if they slowly lowered their body fat percentage over time.

Men's General Body Fat Categories

The ACE categories for men are the same as for women, but the body fat percentages differ. Men need 2 to 5 percent body fat. The recommended athlete range is 6 to 13 percent, and the fitness category covers 14 to 17 percent. As with women, a male runner with a body fat percentage in either the athlete or fitness category would be considered healthy. But he might be able to improve performance while maintaining health by working towards the lower range.

Male Runners' Average Body Fat

In their book, "Better Training for Distance Runners," Peter Coe and David Martin, PhD, address body fat levels for competitive runners. They find healthy trained male distance runners have a body fat between 5 and 8 percent. This places them on the low end of the athlete category used by the ACE. Runners train for many different length events, which usually correlates to their training volume; the longer the race, the more most distance runners run. Coe and Martin found that competitive marathoners had 5 to 7 percent body fat on average, while shorter distance competitors had 6 to 8 percent body fat.

Female Runners' Average Body Fat

Healthy, trained female distance runners have an average body fat of 10 to 14 percent according to Coe and Martin. Following the ACE guidelines, this level is below the recommended athlete level and into the essential body fat category, the minimum necessary level to maintain health and body functioning. Similar to what is found with male runners, body fat tends to be lower the longer the runner's racing distance is. Highly competitive marathon runners have a body fat percentage between 10 and 12 percent, while those training for shorter events have a body fat percentage from 11 to 14 percent.

The Female Athlete Triad

The female athlete triad is the term given to the combination of amenorrhea, osteoporosis and disordered eating. Any female athlete with body fat levels below a healthy level is at risk for this condition. Being thin and running well tend to go hand in hand, at least for a time. Competitive runners face enormous pressure to perform, which can lead to higher training loads and disordered eating patterns. At outlined in "Understanding the Female Athlete Triad," body fat levels that are too low lead to amenorrhea, the cessation of the menstrual cycle. This has negative effects on estrogen levels, which are critical for maintaining healthy bones. If female athletes have low estrogen for prolonged time periods, they risk osteoporosis and other skeletal injuries such as stress fractures, especially because training volume tends to stay at a high level. Female athletes need to maintain a healthy body fat level, which does not prevent a normal menstrual cycle.