Equine Therapy for Autism: New Colorado State Study on Stress

What the new study says about equine therapy for autism

A new randomized trial from Colorado State University found that equine therapy for autism, specifically occupational therapy sessions that include horses, was linked to a bigger short-term drop in the stress hormone cortisol than the same therapy in a clinic. It's a measure of how children's bodies responded during sessions, not proof of long-term change, and researchers frame horses as one tool inside a therapist's plan.

CSU announced the results on Oct. 16, 2026. The paper was published online Oct. 10 in the Journal of Autism and Developmental Disorders and is open access.

The work was done at CSU's Temple Grandin Equine Center (TGEC), which runs programs in Fort Collins and at the CSU Spur campus in Denver. The center is named for Temple Grandin, the CSU animal scientist and autism advocate who is herself autistic.

How the Colorado State trial worked

Here's the setup, in plain terms:

• Who: 72 autistic children, ages 6 to 11.
• Two groups: occupational therapy with horses, or occupational therapy in a regular clinic room.
• Schedule: one hour a week for 10 weeks, led by licensed occupational therapists in both groups.
• Same curriculum: both groups used a modified version of the Zones of Regulation, a program that helps kids recognize and manage their emotions and energy levels.
• In the horse group: children rode with a horse leader and a side-walker alongside.
• What was measured: saliva samples before, during, right after and 20 minutes after sessions.

The lab looked at two markers. Cortisol is a hormone tied to the body's stress response. Salivary alpha-amylase is an enzyme linked to the "fight or flight" side of the nervous system, so it tends to rise with excitement or arousal.

The researchers report that 499 of 504 samples were usable. That matters, because collecting saliva from young children is hard.

What the researchers found

In other words, kids in both groups got calmer during therapy, and the horse group calmed down more by the end. Alpha-amylase went up and came back down in both groups, which the team reads as excitement and engagement rather than distress.

Caiti Peters, a CSU assistant professor of occupational therapy and animal sciences, TGEC's director of research and a co-author, said in the university's release that engagement is a strong predictor of how well therapy works. She said the study shows horses help create a "calm but engaged" state.

The paper also reports exploratory links between cortisol drops and better social functioning scores and less low mood. The authors flag these as preliminary: they used a looser statistical threshold for these tests, and the study wasn't large enough to confirm them.

What this study does not show

Read the result for what it is. Be careful with headlines that go further.

• Short-term only. It measured stress markers around sessions, not how kids were doing months later.
• Secondary outcomes. The trial was sized for its main behavioral goals, and the hormone results were secondary.
• Uneven dropout. More families left the clinic group before therapy began (32%) than the horse group (6%), which complicates comparisons.
• Not a cure. Autism is not an illness to fix. Horses don't treat or cure it; they can make therapy more engaging for some kids.

A separate CSU study, led by Ellen M. Rankins, the paper's first author and a former TGEC postdoctoral researcher, tracked the horses' heart rate and cortisol during sessions. It wasn't part of this paper, but it shows the team is measuring welfare on both ends of the lead rope.

Hippotherapy vs therapeutic riding vs equine-assisted occupational therapy

Most people search for "equine therapy" or "horse therapy for kids." The professionals in the field actually avoid those phrases, because they lump very different services together. The American Hippotherapy Association (AHA) says there's no single service called "equine therapy."

Here's how to tell the main options apart:

• Hippotherapy: a licensed physical, occupational or speech therapist uses the horse's movement as a treatment tool inside a therapy plan. The child doesn't steer; a trained horse handler controls the horse. It's medical therapy, sometimes billed to insurance.
• Occupational therapy incorporating horses: what the CSU trial tested. A licensed occupational therapist works on goals like self-regulation, attention and daily skills, using riding, grooming and barn tasks.
• Therapeutic (adaptive) riding: a riding lesson adapted to the rider, taught by a certified instructor such as a PATH Intl. Certified Therapeutic Riding Instructor (CTRI). The goal is riding skills, independence and fun. It's recreation, not medical therapy.
• Equine-assisted learning or mental health services: mostly ground activities like leading and grooming, often with no riding at all.

The simple question to ask: Is a licensed therapist running this session, or a riding instructor? Both can be valuable. They just aren't the same thing.

How therapy horses are chosen, trained and kept calm

A therapy horse needs a very specific personality. It has to stand still while a child mounts from a ramp, accept a leader and side-walkers crowding it, and ignore balls, toys, sudden noises and unbalanced riders.

There's no single official test for choosing them. An AVSAB (American Veterinary Society of Animal Behavior) summary notes that horses are often retired from this work for behavioral or physical problems. A 2021 study of 30 horses in the journal Animals found that selection still relies heavily on staff judgment and called for more standardized behavior testing.

Good programs usually look for:

• A steady, forgiving temperament. Breed matters less than the individual horse.
• Soundness and smooth, even gaits. In hippotherapy, the movement is the tool.
• A trial period before the horse works with participants.
• Gradual desensitization to ramps, wheelchairs, toys and people walking alongside. See our guide to how to desensitize a horse.
• Ongoing welfare checks: turnout, friends, limited daily sessions, regular vet and farrier care, and time off.

Some of the best therapy horses are second-career athletes. Read about Fury, the ex-racer named the 2026 Thoroughbred of the Year by The Jockey Club's Thoroughbred Incentive Program, in our retired racehorse therapy horse story.

What families should ask before signing up

If you're considering horse therapy for your child, use this checklist on a visit:

1. Who leads the session? For hippotherapy or OT with horses, ask for the therapist's license. For riding, ask about instructor certification, such as PATH Intl. CTRI.
2. Is the center accredited? In the U.S. and Canada, PATH Intl. member centers must have a Certified Therapeutic Riding Instructor (or an approved certification candidate), and Premier Accredited Centers have passed a peer-review site visit. If a program isn't affiliated with PATH Intl., ask about the team's professional training.
3. What are my child's goals? A good program does an intake evaluation and sets goals that fit your child's existing therapy plan.
4. What's the safety setup? Look for a certified riding helmet on every rider, a horse leader, side-walkers when needed, a mounting ramp and a calm, uncrowded arena.
5. How do you handle sensory needs? Ask about quiet times, visual schedules, and what happens if your child gets overwhelmed.
6. How are the horses cared for? Ask how many sessions each horse works per day and how staff spot stress.
7. What does it cost? Prices vary widely by region and service. Many centers are nonprofits with scholarships or sliding scales, and some hippotherapy may be covered by insurance, so call your plan.

Brush up on barn basics before day one with our horse safety for kids guide and our safety hub.

What to do and what to watch next

• Talk to your child's care team before adding horses. Treat it as a complement to speech, occupational, behavioral or other therapies, not a replacement.
• Start with a visit, not a commitment. Let your child watch, pet a horse or groom one first.
• Watch for follow-up research. The authors want future studies to track daily cortisol rhythms and add measures like heart rate variability, and to test larger groups.
• Watch for the horse-welfare results from CSU's parallel study, which could help programs pick and care for therapy horses.
• Not sure about age? See what age kids can start riding, and visit our parents and teachers hub.