From the Guidelines
An estrogen level of less than 15 pg/mL is not normal for a 26-year-old female athlete, even one who participates in intense training like Ironman competitions. This low level indicates hypoestrogenia (low estrogen), which requires medical evaluation. Female athletes, particularly those engaged in endurance sports with low body fat percentages, can develop functional hypothalamic amenorrhea, where intense exercise and potentially low energy availability suppress the hypothalamic-pituitary-ovarian axis, as noted in the 2014 female athlete triad coalition consensus statement 1. This condition leads to reduced estrogen production and often causes menstrual irregularities or absence of periods. Low estrogen in young women can have serious health consequences, including:
- Decreased bone mineral density leading to stress fractures and long-term osteoporosis risk
- Cardiovascular impacts
- Potential fertility issues The athlete should consult with a sports medicine physician, gynecologist, or endocrinologist for proper evaluation, which may include additional hormone testing, bone density assessment, and nutritional analysis. Treatment typically involves addressing energy balance through nutrition adjustments, possibly modifying training intensity, and in some cases, hormone replacement therapy to protect bone health, although the effectiveness of oral estrogen-progesterone combination pills in increasing bone mineral density is still a topic of debate 1.
From the Research
Estrogen Levels in Female Athletes
- Estrogen levels can be affected by athletic activity and energy availability 2, 3
- Low energy availability can lead to reduced estrogen levels, causing menstrual dysfunction and impaired bone health 2, 4
- In female athletes, estrogen levels can vary depending on factors such as athletic activity, energy intake, and menstrual status 3
Normal Estrogen Levels
- There is no specific reference to normal estrogen levels in a 26-year-old female athlete in the provided studies
- However, study 3 found that mean concentrations of log(estrogen/creatinine) were slightly greater in nonathletes who had cycles of <24 or >35 days
- It is essential to note that estrogen levels can fluctuate throughout the menstrual cycle and can be influenced by various factors, including athletic activity and energy availability 2, 3
Estrogen Levels and Athletic Performance
- Low estrogen levels can have negative effects on athletic performance, including decreased bone density and menstrual dysfunction 2, 4
- Energy availability and athletic activity can impact estrogen levels, and female athletes should be aware of the potential risks of low energy availability 2, 4
- More research is needed to understand the relationship between estrogen levels and athletic performance in female athletes 2, 3