Fuelling For Training by Zac Turner

Low Energy Availability & RED-S


The appetite of those in endurance sports is well renowned for being that of large quantities, and this comes with good reason. Our bodies require energy for basic day-today function, and when adding hours of training and exercise on top of this our energy demands increase accordingly, this is known as relative energy. If energy intake and is too low for the physical demands we are performing this may place us in an energy deficient state, better known as RED-S (Relative Energy Deficiency in Sport). This simply means we do not have the energy to fuel our exercise, but the implications of this are far more complex.

Fuelling during training goes further than that of a metabolic level, meaning we need to consider fuelling past the point of just getting through a session. Having low energy availability has a significant influence on our endocrine system, which regulates the release of hormones into our blood stream. Adequately functioning endocrinology is paramount for sporting performance and recovery by the regulation of hormones such as human growth hormone, testosterone and oestrogen. Therefore, failure to meet our energy demands may result in lower hormone levels, which can result in altered bone density, lean mass and vicarial fat, having implications for heightened injury risk and altered performance.


What are some signs that you may be training with low energy availability?

  • Recurrent injuries, specifically bone stress injuries
  • Altered sleep patterns
  • Frequent cold and illness
  • Increased fatigue or lesser ability to back up training sessions
  • Irregular mensural cycles or missed periods (female)
  • Morning erectile dysfunction (males)
  • Lesser sex drive


What are some ideas to prevent RED-S?

  • Fuel in anticipation for training e.g. fuel appropriately for the next day’s training
  • If completing long sessions, fuel during training (gels, sports drink, bars etc.)
  • Refuel with adequate levels of carbohydrate and protein after training, and in a timely manner.
Seek advice from an informed professional, specifically sports dietician.


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