Sleep Disorders in Horses by a Vet – 2025 Guide to Sleep Deprivation, REM, and Collapse 💤🐴
In this article
Sleep Disorders in Horses by a Vet – 2025 Guide to Sleep Deprivation, REM, and Collapse 💤🐴
By Dr Duncan Houston, BVSc
Introduction
Sleep is essential to the health and well-being of horses, just like it is for humans. However, horses have unique sleep requirements and can function on far less total sleep than most other mammals. In 2025, veterinarians recognize that sleep disorders—especially sleep deprivation—can lead to significant performance and health problems, including collapse, injury, and behavioral changes.
How Much Sleep Do Horses Need? 🕒
- Adult horses require only 3 to 5 hours of total sleep per 24 hours
- Most sleep occurs in short intervals throughout the day and night
- Foals and young horses sleep more than adults
- Horses can doze while standing thanks to a stay apparatus, but REM sleep requires lying down
REM Sleep in Horses 💤
- REM (Rapid Eye Movement) sleep is the deepest and most restorative stage
- Horses only spend about 30 minutes per day in REM
- REM sleep only occurs when horses are lying down or fully recumbent
- Lack of REM can lead to neurological fatigue, collapse, and injury
Common Sleep Disorders in Horses ⚠️
1. Sleep Deprivation (Most Common)
- Horses fail to enter REM sleep for days or weeks
- Can result in daytime drowsiness, collapse, and abrasions on knees and fetlocks
- Often mistaken for narcolepsy, which is rare in adult horses
2. Narcolepsy
- True narcolepsy is rare in horses, more common in miniature foals
- Involves sudden loss of muscle tone (cataplexy) often triggered by excitement
- Diagnosis involves EEG and clinical evaluation
Causes of Sleep Deprivation in Horses 🧠
- New or stressful environments (e.g., showgrounds, boarding barns)
- Hospitalization with 24/7 activity and noise
- Pain or musculoskeletal issues that make it difficult to lie down or rise
- Dominance issues in herd setting—low-ranking horses may avoid lying down
Clinical Signs of Sleep Deprivation 👀
- Excessive daytime drowsiness
- Intermittent buckling of front knees (“sleep collapse”)
- Abrasions on front legs (knees and fetlocks)
- General fatigue or irritability
- Unexplained poor performance or behavior changes
Diagnosing Sleep Disorders 🩺
- Often based on clinical signs and behavioral history
- Video monitoring overnight can help detect lack of recumbency or collapse
- EEG and sleep studies available at specialized equine hospitals
Treatment & Management Strategies ✅
1. Address Pain or Lameness
- Check for orthopedic discomfort, laminitis, or arthritis
- Horses in pain may avoid lying down for fear of not being able to rise
2. Improve Environment
- Provide a quiet, clean, and well-bedded stall or soft pasture
- Ensure horse feels safe—avoid aggressive turnout companions
3. Reduce Stress
- Minimize overnight show barn activity
- Allow rest periods between events
4. Monitor Rest & Schedule
- Use video cameras to evaluate rest behavior
- Plan daily quiet time when the horse is undisturbed
Case Example: Show Jumper with Sleep Collapse
- 12-year-old gelding began stumbling during grooming and riding prep
- Veterinarian noted knee abrasions and intermittent collapse
- Video showed no lying down for over 5 days at show barn
- Horse placed on rest in quiet turnout with deep bedding—began lying down
- Resolved within one week with added overnight monitoring
FAQs About Sleep in Horses
Q: How can I tell if my horse is getting REM sleep?
A: Your horse must lie down completely to enter REM. Use video surveillance to confirm this happens daily.
Q: Can sleep deprivation hurt my horse long-term?
A: Yes. Chronic deprivation can cause injuries, behavioral changes, and reduced performance.
Q: Is it dangerous if my horse suddenly collapses?
A: Yes. Sleep collapse from deprivation can cause serious injuries—evaluate and treat right away.
Conclusion
Horses may not need as much sleep as humans, but quality rest and REM sleep are essential for neurological health and performance. In 2025, owners and veterinarians now understand that collapse, skin abrasions, or sudden fatigue may point to sleep deprivation rather than true narcolepsy. Environmental management, pain control, and behavioral monitoring are vital tools in restoring healthy equine sleep cycles.
Need help evaluating your horse’s sleep behavior or signs of collapse? Visit AskAVet.com or download our app 📱 to consult Dr Duncan Houston for 24/7 equine behavior support. 🩺🐴
