Why do Greyhounds sleep all day, and when is it a problem?

A healthy Greyhound that spends most of the day asleep is usually doing exactly what the breed does. It is built for short bursts of very high speed, not for hours of steady work, and most pet Greyhounds are content with a couple of walks, a safe chance to run, and a soft bed for the rest of the day. Published measurements of Greyhound sleep time are hard to find, so the 18 to 20 hours often quoted by owners is best read as an estimate rather than a research figure. What matters more is each dog's own normal, and noticing when it changes.

Built for a sprint, not a long run

Greyhounds are fast, though not quite as fast as popular figures suggest. A comparative anatomy study of cheetahs and Greyhounds put the racing Greyhound's top speed at about 17 meters per second, roughly 61 km/h (38 mph). The 72 km/h figure repeated in breed descriptions is higher than the figure that study used. Either way, a Greyhound reaches its top speed quickly and holds it only over a short distance.

A flat-out sprint uses muscle fuel fast and generates a lot of heat, and the dog needs time afterwards to recover and cool down. A pet Greyhound that has had a hard gallop around a field will often flop down and sleep deeply afterwards. That pattern of bursts followed by long rest is typical of the breed and is not a sign of poor fitness.

Muscle and blood made for speed

Greyhound muscle is unusual. In a classic study comparing Greyhounds, crossbred dogs and Foxhounds, the Greyhound had a significantly higher proportion of fast-twitch fibers in every muscle examined, close to 100% in most of them. Fast-twitch fibers contract powerfully and quickly. It is the muscle profile of a sprinter.

The blood is different too. A review of Greyhound and sighthound clinical pathology describes a higher red blood cell mass, higher creatinine and liver enzyme values, and lower white blood cell, neutrophil and platelet counts, total globulins and thyroid hormone (T4) than in other breeds. More red cells means more oxygen delivered to working muscle. It also means that a Greyhound's normal blood test can look abnormal when it is judged against ranges set for other dogs.

Settling in after racing

Many pet Greyhounds are retired racers, and a kennel routine is very different from a house. Stairs, glass doors, slippery floors, mirrors and household appliances may all be new. Some dogs are unsure of them at first and need time and patience rather than pressure.

• Floors: rugs or runners on smooth floors help a long-legged dog with little body fat get up and lie down without slipping.
• Beds: a thick, padded bed matters for a lean, bony dog that spends much of the day lying down.
• Sleep: some dogs startle if touched while deeply asleep. Call the dog's name and let it wake before touching it, and teach children to do the same.
• Routine: regular times for meals, walks and rest help a dog used to a fixed kennel schedule settle.

Owners often describe Greyhounds sleeping on their backs with all four legs in the air, a position some call roaching. It is a common sight in relaxed pet Greyhounds and nothing to worry about.

How much exercise a Greyhound needs

The American Kennel Club describes the breed as perfectly happy to lounge around the house all day, but still needing a regular schedule of exercise and chances to run full-out safely. A workable routine for most dogs is two walks a day plus, when possible, a gallop in a securely fenced area. The AKC is clear that Greyhounds should be off the leash only in fenced areas, because the urge to chase something that moves can override recall.

Warm up with a walk before a sprint, and keep hard running for cooler parts of the day in hot weather. A lean dog with a short coat also feels the cold, so a coat on winter walks is sensible.

Weight still needs watching. The AKC gives adult males as 65 to 70 pounds (29 to 32 kg) and females as 60 to 65 pounds (27 to 29 kg), and a retired racer used to a working ration can put on weight once its life becomes quieter. Greyhounds carry very little body fat, so a dog at a healthy weight looks leaner than a heavier breed would. Ask the vet to show what good condition looks like on that particular dog.

When sleepiness is a warning sign

Because the baseline is so much rest, the change matters more than the total. A Greyhound that is sleeping clearly more than its own normal, is slow to get up, refuses walks or meals, or seems dull when awake for more than a day or two needs a vet check.

• Lameness or bone pain: osteosarcoma, a malignant bone tumor, is well recognized as common in Greyhounds. A limp that does not settle within a few days, or a firm swelling on a leg, needs an examination and usually an X-ray.
• Bloat: the AKC notes that, like most deep-chested breeds, Greyhounds are susceptible. Restlessness, a swollen belly, drooling and retching without bringing anything up are an emergency at any hour.
• Dental pain: in UK primary-care records, periodontal disease was recorded in 39% of pet Greyhounds in a single year, the most common disorder in the breed. A sore mouth can make a dog quiet and reluctant to eat. The same study found neoplasia to be the most common cause of death.
• Suspected thyroid disease: lethargy and weight gain can suggest hypothyroidism, but healthy Greyhounds normally have lower T4 than other breeds. A low T4 result on its own is not enough to diagnose the disease in this breed, and the vet should interpret it with Greyhound reference ranges and further tests.

For blood results generally, it helps to mention the breed when a dog is seen by a new practice. A packed cell volume or platelet count that would prompt more tests in a Labrador may be normal for a Greyhound.

Sources

1. Functional anatomy of the cheetah (Acinonyx jubatus) forelimb. Journal of Anatomy, 2011.
2. Skeletal muscle fibre composition in the dog and its relationship to athletic ability. Research in Veterinary Science, 1981.
3. Clinical pathology of Greyhounds and other sighthounds. Veterinary Clinical Pathology, 2011.
4. Greyhound dog breed information. American Kennel Club.
5. Markers of iron metabolism in retired racing Greyhounds with and without osteosarcoma. Veterinary Clinical Pathology, 2013.
6. Greyhounds under general veterinary care in the UK during 2016: demography and common disorders. Canine Genetics and Epidemiology, 2019.