The Symptoms

Whilst every case of RED-S is complex and unique, most athletes experience some combination of the symptoms below. The RED-S CAT™ Clinical Assessment Tool (CAT) can be a useful resource for exploring these further.

Physical sign How to spot / monitor them
Unexplained fatigue/lacking energy
Recurrent or persistent injuries (including bone and soft tissue injuries)
Recurrent or persistent illness
Difficulty adapting to training
Performance stagnation or deterioration
Make a note of anything you’ve been experiencing over the past few months: illnesses, injuries, niggles, inconsistencies in training, fatigue, changes in mood, difficulty adapting to training or generally poor performances.

Consider keeping a training diary to keep track of your experiences: jot down your daily exercise activity and make a note of how you're feeling day-to-day.

Consider logging your food and exercise for a few weeks or months to help assess your energy intake and expenditure, but please see 'challenges to be aware of' below before deciding whether this is the right step for you.

If you've experienced a bone-related injury (or multiple) and haven’t already had a bone density test via a DEXA scan, try to do so via your GP, sports doctor or a RED-S for specialist help (see Resources page of this website).
Secondary amenorrhea (missing or irregular periods) Consider whether you’ve experienced any signs of menstrual disturbances or missing periods over the past few months and please note, a withdrawal bleed from an Oral Contraceptive Pill is NOT a period. I know it may look and feel similar, but it is entirely different and if you’re a female experiencing other signs of RED-S, it’s more than possible your natural period would be missing. If you are showing subtle signs of menstrual disturbance e.g. a longer length of time between periods, then tracking your symptoms via a mobile app like FitrWoman can be really helpful.
Primary amenorrhea in females (not starting their period by the age of 15) If you're over the age of 15 and haven't yet had your first period, work with your doctor to rule out any other possible reasons for this before looking into RED-S further.
Low libido (in males and females) Keep tabs on your sex drive (if you're of the age to have one) to check for signs of hormonal disruption. Make a note on whether it’s been lower than usual or absent completely. This is a sign your endocrine system is lacking in fuel to direct towards 'non-essential' functions.
Iron deficiency Ask your GP to check your ferritin levels and make sure when you ring up for the results, you are given the actual number rather than be told you’re in the ‘normal range’ – since this differs for athletes (more advice on this here).
Scoring low on an energy availability scale If you have access to physiological testing (e.g. bioimpedence machines, university laboratories) then use whatever you can to calculate your fat free mass. If not, you can estimate your energy availability in relation to the amount of exercise you’re doing by using the following formula:

Energy Availability (EA) = energy intake (EI) minus exercise energy expenditure (EEE). As a guideline, healthy athletes have 45 kcal/kg FFM (Fat-free Mass). Maintaining a normal resting metabolic rate requires 30 kcals/kg FFM. EA lower than 30 kcal/kg FFM is considered alarming. If EEE is very high and EI is low, then EA is out of balance and vice versa.
Psychological signs Try to answer these questions as accurately and honestly as possible
Increased irritability/poor concentration/depression
Unwillingness to take rest days (including continuing to train when in pain or unusually fatigued)
Anxiety around meal times or avoidance of eating certain food groups e.g. carbs/fats
An irrational fear of weight gain
Feeling the need to ‘earn your food’
Body dissatisfaction: untrue belief that changing body size/shape will result in being better or happier
How do you feel about your weight?
Are you trying to lose or gain weight?
Do you think that losing weight could improve your performance?
Are there certain foods you try to avoid or eliminate from your diet?
Do you feel a need to exercise to ‘earn’ your food, eating less on rest days than you would on training days?
Do you try to avoid rest days from training or feel an urge to make them ‘active’ rest days?
Do you think about food a large percentage of the time?
Do you find it hard to sit down and truly rest?
Do you find yourself sticking rigidly to exercise plans – even if it means ignoring your bodies signals e.g. when you’re tired or in pain?
Do you think you might have an eating disorder?
Do you think you display some disordered eating behaviours?