The Claim

Fourteen days of low energy availability at 22 kcal/kg fat-free mass per day in female endurance athletes increases resting systemic cortisol levels by 22% and alters the plasma inflammatory proteome by reducing CST5, FGF-21, Flt3L, IL-18R1, and VEGFA while increasing beta-NGF and CCL28, without elevating hsCRP or IL-6.

Source: Low energy availability increases immune cell formation of reactive oxygen species and impairs exercise performance in female endurance athletes

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
71score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

In female endurance athletes, consuming only 22 kcal per kilogram of fat-free mass per day for 14 days raises resting cortisol levels by 22% and changes the levels of seven plasma proteins involved in immune regulation—five decrease and two increase—without affecting standard inflammatory markers like hsCRP or IL-6.

See the scientific wording

Fourteen days of low energy availability (22 kcal/kg fat-free mass/day) in female endurance athletes increases resting systemic cortisol levels by 22% and alters the plasma inflammatory proteome, reducing five immune-related proteins (CST5, FGF-21, Flt3L, IL-18R1, VEGFA) and increasing two (beta-NGF, CCL28), without elevating classic inflammatory markers like hsCRP or IL-6.

Why this might work

When athletes don't eat enough to match their training, their body releases more stress hormone, which tells immune cells to make more reactive chemicals called ROS. These chemicals change the signals sent by immune cells in the blood, turning down some immune proteins and turning up others, but they don't trigger swelling or fever. This shift happens without activating the usual inflammation pathways.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Low energy availability increases immune cell formation of reactive oxygen species and impairs exercise performance in female endurance athletes

    When female athletes don’t eat enough calories for their training for two weeks, their body releases more stress hormone (cortisol) and changes some immune signals in the blood—but doesn’t trigger the usual signs of inflammation like swelling or fever.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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