Physical Activity and Sex Steroid Hormones in Women: A Prospective Study

This study confirmed that energy expenditure alone, even when not leading to negative energy balance, is sufficient to cause modest changes in ovarian function. Even moderate increases in physical activity can lower progesterone levels, reducing the chance of conception in a cycle and also the cumulative lifetime hormonal exposure. These findings highlight the importance of encouraging regular physical activity, particularly in premenopausal women, as a strategy to modulate hormone levels, maintain reproductive health, and potentially reduce the long-term risk of hormone-related cancers.