RED-S: when training outruns fuelling

What RED-S is, the warning signs to know, and why losing your period during heavy training is a warning sign your body needs more fuel — not a sign of fitness.

Rowing asks a lot of a young body. Early mornings, long pieces on the water, sessions in the gym — all of that takes energy, and that energy has to come from somewhere. RED-S stands for Relative Energy Deficiency in Sport. It happens when someone training hard isn't taking in enough fuel to cover both the training and everything else a growing body needs to do — repairing tissue, building bone, keeping hormones working properly.

It's easy to think of this as purely an "eating" problem, but it isn't only about how much someone eats. It can also happen when training goes up a lot without fuelling catching up, or during a busy patch of school and racing when meals get rushed or skipped. The result is the same either way: the body is short of the energy it needs.

The warning signs

RED-S can show up in several ways, and often more than one at once:

• Feeling tired more than usual, even after a full night's sleep
• Performance that stalls or drops despite training going well on paper
• Getting ill or picking up niggling injuries more often than before
• Struggling to concentrate at school
• Feeling cold when others don't
• For girls and young women: periods becoming irregular or stopping

The one thing every young rower should know

Losing your period during heavy training is a warning sign that your body needs more fuel — not a sign of fitness. It can feel, on the surface, like a sign of being lean and in good shape. It is the opposite. A missing period usually means the body has decided there isn't enough energy coming in to keep every system running, so it quietly switches off the ones it judges least urgent in the short term — and the reproductive system is often first. Left unaddressed, this affects bone strength, makes injuries more likely, and can hold back the very performance training is meant to build. It is a signal worth listening to, not a target to aim for.

Why this matters for a growing body

Teenage years are when bones lay down most of their lifetime strength. Training under-fuelled during this window doesn't just cost performance now — it can leave bones weaker for years afterwards, long after racing has stopped. That's part of why coaches and welfare staff take early signs seriously rather than waiting for a big, obvious problem.

What actually helps

The fix is rarely complicated: matching what goes in to what training asks for, and making sure meals and snacks are regular rather than an afterthought — especially around sessions and on busy double-training days. This isn't about strict rules or being told exactly what to eat; it's about noticing the pattern and adjusting it, with support from people who know what they're doing.

For parents and guardians

RED-S can be easy to miss because the early signs — tiredness, a stalled personal best, one more cold than usual — look ordinary on their own. If your daughter mentions her periods have become irregular or stopped, or if training seems to be taking more out of your child than it should, it's worth a conversation rather than a wait-and-see approach. Clubs would always rather hear about this early.

Who to talk to

If any of this sounds familiar, you don't have to work it out alone. Your club's welfare officer is there for exactly this, training is confidential, and reaching out doesn't need to go through a coach first. A GP is the right person for anything physical, including irregular or missing periods. And a trusted adult — a parent, a teacher, a coach you get on with — is always a reasonable place to start if you're not sure who else to ask.

Last updated 2026-09-13