“But exercise is healthy….right?” Overtraining syndrome and Relative Energy Deficiency in Sport (RED-S) in the recreational runner: a primer for clubs and training groups
Think about the people in your running club. There will be someone who springs to mind: the member who has to enter every race, attend every training day, join every group run and interval session and track workout. Their weekly mileage spirals up, their times improve, they might lose weight, and they get lots of praise from club mates and colleagues. Having started from a lower level, the improvements they make are exponential; every race is a PB. Before long they’ve run a spring marathon, and are now ready to take on the summer road racing circuit, before throwing themselves into cross country through the winter.
They have a basic understanding of how fitness works, and know that the progressive overload approach that they employed as a novice runner gave them huge rewards. The weight loss that came easily at first now stalls as their metabolism stabilises, and they start looking more closely at their food and nutrition. They find their way to blogs and opinion pieces by influencers or famous runners, and cut out certain food groups or restrict their eating in specific ways. Uncoached, and following patchy threads of information on the internet, they keep pushing on. Running is their thing. It is heathy. Right?
However, cracks start to appear. It might start as a calf strain, or a sore Achilles. A bit of plantar fasciitis. The kind of small niggles that all runners face. The runner has learned the habit of mental toughness – push through, keep going, no pain no gain. It is just a niggle, besides, with the club 5 mile championships coming up, stopping is not an option!
After a while, they don’t feel great on an increasing number of runs. Legs feel heavy, heart rate too high for a pace that “should” feel easy. Management of niggles becomes a second job– kinetic tape, physiotherapy, special shoes. They feel exhausted and hungry, but tell themselves this is completely normal – everyone feels tired when training for a marathon. And you have to be careful not to “eat back your calories” and gain weight. 10k doesn’t feel like sufficient running to allow for that slice of cake with friends. The mental toughness that got them through their first marathon when things started to feel hard at mile 22 now turns against them, berating them not to be weak, not to give in. Other runners run far more and are fine. So they keep going. This process can play out over months or even years, with the runner gradually piling on the training stress, not recovering sufficiently, and slowly pushing their body into a state of dysfunction.
Other symptoms start to creep in. Subtle at first, if they keep training, they become progressively worse. They realise that they are frequently waking at 3am, soaked in sweat. Their legs are cramping or aching at rest and no amount of foam rolling can get rid of the pain. Their heart rate soars when walking upstairs at work. If female, they might notice that their periods are changing, getting lighter, their cycles might get longer, and eventually they might lose their cycle completely. If male, their sex drive might be missing in action. They might feel cold constantly, or develop Reynaulds disorder or other circulatory problems. Still running, their times stagnate or regress. Eventually, they get a “proper” injury – a stress fracture or a significant soft tissue tear.
What has been described here is a medical condition that can effect athletes at all levels. The hypothetical runner described above could be suffering from two closely inter-related areas of dysfunction: overtraining syndrome (OTS) and RED-S (relative energy deficiency in sport). It is possible to have one without the other, but they are often seen together, and some scientists now believe that overtraining syndrome itself is a symptom or expression of the broader diagnosis of RED-S. Both are reactions by the body’s metabolic, hormonal and physiological systems to extreme stressors: whereby the athlete has stressed their body beyond what it is capable of functionally recovering from. In OTS the primary stressor is aerobic exertion without corresponding recovery; in RED-S the primary stressor is low energy availability, i.e. too few calories for the work required of the body. The main culprit for the symptoms experienced by the athlete is this state of low energy availability, which can stretch over a period of days, weeks, or even years.
Low energy availability (LEA) is a fundamental cause of stress on a systemic level, and it initiates a cascade of hormonal and metabolic disruption in the body, leading directly to the symptoms described in our hypothetical athlete case study. LEA can be accidental – when an athlete simply doesn’t realise that they are not sufficiently fuelling their body for the work required; or it can be deliberate, as a result of disordered eating, or deliberate weight management. Once in a state of LEA, the body’s equilibrium is significantly disrupted, leading to a web of issues as laid out in the infographic below:
The most significant and long term issue that can be caused by LEA is impaired bone health. This can effect both male and female athletes, although it is more easily recognised in females as the link between oestrogen production and bone health has been well studied. If a woman lacks a regular reproductive cycle, her body is not producing oestrogen, which means her bone density will be seriously inhibited. In men, the clear signal provided by the presence or absence of a menstrual cycle does not exist. However, LEA will result in reduced testosterone in men, which carries a similar impact on bone health. Low testosterone can present as low or absent libido, erectile dysfunction, depression or loss of muscle tone in trained male athletes. Any of these symptoms should be investigated in male athletes who are at risk of LEA. For athletes in general, the main consequence of LEA and impaired bone turnover is the increased likelihood of stress fractures or full fractures, especially in the lower limbs (tibia, fibula, metatarsals or other foot bones) or in the hip/pelvis area or lower back.
Overtraining syndrome and RED-S can be extremely distressing for an athlete to deal with psychologically as well as physically. Within a club culture, the fear of missing out on a social scene that has become integral to the life of a member is one reason why a runner might not be willing to take a rest or a break when they might need it. It is easy to forget the very basic tenet of exercise physiology: adaptations are made at rest – if you don’t recover from a session, you might as well not have done the session at all. Also remember that as a runner, you are probably very self-motivated. You want to run. If you find yourself dreading your run or not wanting to do it, it is probably a good sign that your body might be asking you to take a break.
If you or any of your club mates are complaining of any of the following symptoms, think about seeking advice from one of the coaches in the club, the club welfare officer, or an outside source of support:
• High resting heartrate that lasts for a number of days without obvious reason (infection, etc.)
• Sustained high heartrate on “easy” runs
• Feeling out of breath or tired walking up stairs, or feeling exhausted carrying shopping/doing normal household tasks
• Frequent night sweats
• Unexplained leg cramping or pain at rest
• Feeling of “heaviness” that lasts for a number of days or sessions
• Any menstrual disruption in women should be investigated immediately and if more than one cycle is missed, and the athlete is at risk of LAE, it should be addressed as a matter of urgency
• In male athletes, any changes to libido or sexual function should be treated as a possible red flag for LEA and RED-S.
Note that RED-S can impact all body shapes and sizes and there isn’t a specific body fat % or BMI that is “safe”. Energy availability is distinct to the individual, their physiology and work output, and not necessarily directly proportional to their relative body size, mass or composition.
Special considerations to be aware of for athletes with disordered eating and exercise addiction/compulsion:
• Comments about dissatisfaction with body shape/size, or about the bodies of other athletes
• Food restriction in scenarios where other people are eating (i.e. post run snacks, recovery nutrition etc).
• Doing a lot of fasted runs (this is particularly dangerous for women and can be very stressful on the body)
• Cutting out entire food groups without medical reason (i.e. cutting all carbs)
• Turning up to group runs when obviously injured/sick/exhausted
• An all or nothing attitude to training (if I miss this run I might as well jack in the entire training cycle)
• Comparing themselves to others and trying to run the most miles per week or top the Strava rankings week after week without rest.
If any of these symptoms or behaviours are familiar, there are resources available for advice and help below.
NB: There will be a TrainBrave event in Oxford on Sunday 23rd June, sign up for free on the website. Their events are highly recommended.
British Journal of Sports Medicine, most recent paper on RED-S:
1st May 2019