Athletic Endurance After Eating Disorder Recovery

For many athletes and parents, the hardest part is not the diagnosis itself. It is the quiet fear that follows it:

“Will my child ever have the same strength again?”

“Will I be able to train without falling back into old habits?”

“Why does even a small workout feel harder now?”

Recovery can feel frustrating at first because endurance does not return in a straight line. It is not a simple matter of “getting back in shape.” It is about teaching the body to trust food again, teaching the mind to trust rest again, and teaching the athlete to see performance as something built on health, not punishment.

Why pushing harder doesn’t work

It’s natural to think:

“I just need to train more.”

But in recovery, more training without enough fuel = more damage.

• The body cannot rebuild without energy
• Overtraining can delay recovery
• It increases the risk of relapse

Important shift: Progress comes from fuel + rest + gradual training—not from intensity alone

Why does endurance drop during an eating disorder?

1. Depleted glycogen (your main fuel source). Glycogen is the body’s stored form of carbohydrates, found in muscles and the liver. It is the primary fuel for endurance exercise.

In under-fueling, glycogen stores are chronically low

The body runs out of quick energy faster

The brain also senses low energy and increases fatigue signals

it starts producing more stress hormones and shuts down production of reproductive hormones.

Result: early fatigue, reduced stamina, “hitting a wall” sooner

2. Muscle breakdown instead of muscle building. When energy intake is insufficient, the body begins to break down muscle tissue for fuel (catabolism).

• Reduced protein synthesis
• Loss of lean muscle mass
• Decreased strength and power output

Result: weaker performance, lower endurance capacity, faster exhaustion

3. Impaired cardiovascular efficiency. Endurance relies on how well the heart and lungs deliver oxygen to muscles.

In an energy-deficient state:

• Stroke volume (blood pumped per beat) may decrease
• Heart rate response becomes less efficient
• Reduced blood flow to working muscles
• VO2 max is reduced

Result: you feel more “out of breath” at lower intensities

4. Hormonal disruption (RED-S). Low energy availability disrupts key hormones involved in metabolism, recovery, and adaptation.

Common changes:

• ↓ Estrogen/testosterone → affects muscle, bone, and recovery
• ↑ Cortisol (stress hormone) → increases fatigue and muscle breakdown
• ↓ Thyroid hormones → slow metabolism and energy production

Result: poor recovery, fatigue, decreased training adaptation, decreased bone formation (osteopenia)

5. Slowed recovery and repair. Recovery is where endurance is actually built.

With under-fueling:

• Reduced muscle repair after workouts
• Increased inflammation
• Impaired mitochondrial function (energy production at the cellular level)

Result: persistent soreness, fatigue, and inability to improve despite training

What this looks like in real life

Even if someone continues training, the body is not adapting properly.

Common effects:

• Early fatigue (workouts feel harder than before)
• Reduced strength and endurance
• Slower recovery between sessions
• Plateau or decline in performance
• Increased risk of injury or burnout

What parents and athletes may notice

For athletes:

• “I’m training the same, but getting worse.”
• Needing more effort for less output
• Feeling constantly tired or unmotivated
• not running as fast, not swimming as fast, no throwing as fast

For parents:

• Increased fatigue or low energy
• Mood changes or irritability
• Obsessive focus on exercise or food
• Declining performance despite continued effort

How to Safely Rebuild Endurance

(Clinical, Evidence-Based Approach)

1. Nutritional Rehabilitation

Adequate energy availability is the cornerstone of recovery.

Patients should be guided toward:

• Regular, structured meals and snacks throughout the day
• Adequate total energy intake to meet metabolic and activity demands
• Inclusion of all macronutrients (carbohydrates, proteins, fats) without categorization as “good” or “bad” foods
• Emphasis on variety, flexibility, and adequacy, rather than restriction or optimization

2. Medical Stabilization and Monitoring

Before progression in training:

• Assess vital signs, weight trends, and laboratory markers
• Monitor for RED-S indicators (e.g., menstrual dysfunction, low bone density, fatigue)
• Evaluate cardiovascular status if prolonged undernutrition occurred

3. Gradual Reintroduction of Physical Activity

Exercise should be prescribed, not self-directed, during recovery.

Initial phase:

• Low-intensity, non-compensatory movement (e.g., walking, light aerobic activity)
• Short duration, with clearly defined limits
• Supervised or guided where possible

Focus:

• Re-establishing tolerance to movement
• Reducing fear or compulsion around exercise
• Separating exercise from caloric compensation

4. Strength Restoration Prior to Endurance Loading

Emerging evidence (2022–2024) supports prioritizing resistance training in recovery phases.

Goals:

• Restore lean muscle mass
• Improve neuromuscular function/nervous system recalibration
• Enhance injury resilience

5. Controlled and Measured Progression of Training Load

Training progression should follow gradual, individualized increments in:

• Duration
• Frequency
• Intensity

Avoid:

• Sudden increases in training volume
• Exceeding physiological readiness

Monitor for red flags:

• Persistent fatigue
• Dizziness or lightheadedness
• Mood instability
• Compensatory urges (e.g., need to “do more”)

6. Psychological and Behavioral Interventions

Endurance recovery requires parallel psychological rehabilitation.

Common comorbid features:

• Perfectionism
• Anxiety disorders
• Obsessive-compulsive traits
• Compulsive exercise behaviors

Recommended interventions:

• Cognitive Behavioral Therapy (CBT) for maladaptive beliefs around food, body, and exercise
• Dialectical Behavior Therapy (DBT) for emotional regulation and distress tolerance
• Family-Based Therapy (FBT) for adolescents

7. Role of the Multidisciplinary Team

Optimal recovery outcomes are achieved through coordinated care involving:

• Physician (medical monitoring)
• Registered Dietitian (nutritional rehabilitation)
• Therapist/Psychologist (behavioral and emotional support)

Regular communication among providers ensures:

• Safe progression of activity
• Consistent messaging
• Early intervention if relapse risk increases

8. Parental Support (SMART & Therapeutic Approach)

Parental involvement should be structured, supportive, and non-judgmental, particularly in adolescents.

Specific

• Establish consistent meal and snack routines at set times daily
• Support attendance in all medical, nutrition, and therapy appointments
• Help maintain structured rest periods and limits on exercise

Measurable

• Monitor observable behaviors (e.g., meal completion, attendance, adherence to activity limits)
• Track consistency rather than perfection

Attainable

• Set realistic expectations for recovery pace
• Focus on small, consistent improvements rather than rapid change

Relevant

• Align all support with the treatment plan provided by healthcare professionals
• Reinforce health, safety, and long-term well-being over performance

Time-bound

• Reassess progress regularly with the care team (e.g., weekly or biweekly check-ins)
• Adjust expectations based on clinical feedback

Therapeutic Communication for Parents

• Use neutral, supportive language (avoid comments on weight or appearance)
• Validate emotions without reinforcing disordered behaviors
• Encourage openness: “How can I support you today?”
• Maintain consistency and boundaries around meals and activity

9. Watch out for Warning Signs Requiring Clinical Reassessment

Immediate reassessment by the care team is indicated if:

• Exercise persists despite medical or physical contraindications
• Strong guilt or anxiety occurs with rest
• Rigid or restrictive eating patterns re-emerge
• Menstrual dysfunction, dizziness, or syncope occurs
• There is a return of compulsive or compensatory behaviors

Conclusion

Endurance drops not because of a lack of effort, but because the body does not have the resources to sustain performance.

Without enough fuel, the body shifts from performance mode → survival mode

And in survival mode, endurance is no longer the priority.

References

Vardardottir, B., Olafsdottir, A. S., & Gudmundsdottir, S. L. (2023). Body dissatisfaction, disordered eating and exercise behaviours: Associations with symptoms of relative energy deficiency in sport (REDs) in male and female athletes. BMJ Open Sport & Exercise Medicine, 9(4), e001731. https://doi.org/10.1136/bmjsem-2023-001731

Ibáñez-Caparrós, A., Sánchez, I., Granero, R., Jiménez-Murcia, S., Rosinska, M., Thiel, A., Zipfel, S., de Pablo, J., Camacho-Barcia, L., & Fernandez-Aranda, F. (2023). Athletes with eating disorders: Analysis of their clinical characteristics, psychopathology and response to treatment. Nutrients, 15(13), 3003. https://doi.org/10.3390/nu15133003

Castañeda, M., et al. (2023). The impact of anorexia nervosa and the basis for non-pharmacological interventions. Nutrients, 15(11), 2594. https://doi.org/10.3390/nu15112594

Healy, D. R., Mansson, N., Furu, M., Bratlandsanda, S., & Sjögren, J. M. (2024). Maximal resistance training in the treatment of anorexia nervosa: A case report series. International Journal of Exercise Science, 17(3), 308–326. https://doi.org/10.70252/GEJG3591

Halbeisen, G., Timmesfeld, N., & Paslakis, G. (2025). Reducing the urge to be physically active in patients with anorexia nervosa through virtual reality: Protocol for a randomized controlled feasibility trial. BMJ Open, 15(1), e097886. https://doi.org/10.1136/bmjopen-2024-097886

Bongiorno, V., & Heaner, M. (2025). Resistance training is an underused and promising tool in eating disorder recovery: A narrative review. Journal of Eating Disorders, 13, 123. https://doi.org/10.1186/s40337-025-01305-y

Colangelo, J., Smith, A., Henninger, K., & Liebrenz, M. (2025). Exploring the presentation of relative energy deficiency in sport (REDs) in ultra-endurance sport: A review. Journal of Eating Disorders, 13, 210. https://doi.org/10.1186/s40337-025-01381-0

Clinical Psychology Review Meta-analysis Group. (2025). A meta-analysis of mortality rates in eating disorders: An update of the literature from 2010 to 2024. Clinical Psychology Review, 116, 102547. https://doi.org/10.1016/j.cpr.2025.102547