We could not find a published study that sets a safe number of minutes for lunging, so treat the widely repeated "20 minutes" as a convention, not a finding. What research does show is that the circle itself changes how a horse loads his legs: the outside front leg takes a higher peak vertical force than the inside one, sideways forces appear that a straight line does not produce, and a hard surface makes those sideways forces larger. So keep sessions short, circles large, directions even and footing forgiving, and stop when the horse is working well, not when a timer says so.
If you have been lunging for twenty minutes because everyone says twenty minutes, this page explains what that number is and is not, and what to decide on instead.
Where "20 minutes" comes from
Most advice on this question gives a range around 10 to 20 minutes, or a hard cap of 20 or 30. We looked for the study behind the figure and did not find one. That does not make it a bad rule of thumb. It means it is a rule of thumb, and the reasons behind it are more useful than the number.
The reason people give is the circle. On that point there is real research.
What the circle does to his legs
The forces are uneven, and some go sideways. Chateau and colleagues measured ground reaction forces in both front legs of six horses trotting on circles on different surfaces, published in The Veterinary Journal in 2013 (Europe PMC record, read 2026-09-11). The inside forelimb produced a smaller peak vertical force with a longer stance phase than the outside forelimb, and circling generated substantial outward transverse forces, meaning sideways loading that straight-line work does not create. On a soft sand surface, peak transverse forces and moments were significantly lower than on asphalt, which the authors explained by the hoof sinking into a more compliant surface.
Smaller and faster means more lean. Pfau, Stubbs, Kaiser, Brown and Clayton studied eleven dressage horses lunging at speeds from 1.5 to 4.7 meters per second on circles with radii from 1.8 to 11.2 meters, in the American Journal of Veterinary Research in 2012 (Europe PMC record, read 2026-09-11). Body lean on the circle could be predicted from radius and speed, and most measures of movement symmetry changed as lean angle changed. In plain terms, a tight circle at speed asks for more lean, and more lean changes how he moves.
Even sound horses move unevenly on the lunge. Rhodin and colleagues measured 94 horses that moved symmetrically on a straight line, in Equine Veterinary Journal in 2016 (Europe PMC record, read 2026-09-11). Their head and pelvic movement was more asymmetric on the lunge than on the straight, often differently in each direction, and the authors concluded that lungeing induces systematic asymmetries that "may mask or mimic" lameness. Marunova, Hernlund and Persson-Sjödin, studying 76 riding horses in PLoS One in 2024 (Europe PMC record, read 2026-09-11), found the circle altered pelvic asymmetries in horses that already had them, while surface type had no significant effect on the asymmetry measures they used.
What that means for your session. Every minute on a circle is a minute of uneven, partly sideways loading. The minutes matter, but so do the circle size, the speed, the surface and the direction, and those are the parts you control.
How hard is lunging, as exercise?
Harder than it looks from the middle. Huangsaksri and colleagues put 16 untrained ponies through two traditional lunging protocols and reported in the Journal of Equine Veterinary Science in 2024 (Europe PMC record, read 2026-09-11) that cantering reached moderate intensity, around 75 percent of maximum heart rate on average, with occasional high-intensity peaks around 88 percent. Heart rate variability took up to 120 minutes after exercise to recover.
That is a fitness workout for an unfit animal, not a leg-stretch. If you want to know how hard your own horse is working, learn to take his heart rate properly and watch how quickly it comes down afterward, against his own resting normal.
How young is too young?
This is where the most confident advice has the least evidence behind it, in both directions.
Rogers, Gee and Dittmer reviewed equine growth and skeletal maturity in Animals in 2021 (Europe PMC record, read 2026-09-11). They report that the horse completes the equivalent of rapid infant growth by weaning at four to six months, the childhood phase at about eleven months, and by two years has reached most of the measures of maturity used in human studies, including closure of growth plates. They argue that the popular case against exercising young horses is often "in contrast to the scientific literature" and wrongly framed by comparison with human growth.
A companion review by Rogers and Dittmer in Animals in 2019 (Europe PMC record, read 2026-09-11) proposes that foals' spontaneous, vigorous play loads their bones in the way that promotes healthy development, and recommends that management gives foals the opportunity for it.
What that does not tell you. Neither review studies lunging. Free movement in a field, where a young horse chooses his own speed, direction and turns, is not the same as repeated circles at the speed a person sets. The research supports young horses moving. It does not give an age at which lunging becomes safe, and we will not invent one. Talk to your veterinarian about your young horse specifically, and keep any circle work large, slow and brief.
When lunging does harm
- When he is sore. Merck names pain as the most common cause of lameness in horses (Overview of Lameness in Horses, Stephen B. Adams, DVM, DACVS, last reviewed August 2025, read 2026-09-11). Lunging a lame horse to "work him out of it" loads a painful leg on a circle, and the asymmetry research above means you may not even see what is wrong.
- On hard or slippery footing. The Chateau study found larger sideways forces on asphalt than on sand.
- On small circles at speed, which increase lean.
- In one direction more than the other. Circle work loads the inside and outside legs differently, so change direction regularly and keep the totals even.
- As a substitute for turnout. Mississippi State University Extension does recommend that "fresh" horses be tacked up and lunged "to allow them to release stored energy" before work (Safety Awareness with Equine, read 2026-09-11). That is a safety use before riding. It is not a replacement for the free movement a horse gets in a field.
How long should I lunge my horse? Decide these instead
Instead of a number, decide on these, in this order:
| Decide | Why it matters |
|---|---|
| The purpose: warm-up, taking the edge off, fitness, or letting your vet see him move | A warm-up before riding needs far less than a fitness session |
| The largest circle your space allows | Smaller circles at speed increase lean |
| Mostly walk and trot, with canter in short spells | Canter pushed untrained ponies to moderate and occasionally high intensity |
| Both directions, evenly | Each direction loads the legs differently |
| The softest safe surface you have | Hard surfaces increased sideways forces |
| How he recovers | His heart rate afterward tells you whether the session was the right size |
Stop early if he starts to look uneven, trips or stumbles, bobs his head, his breathing does not settle during walk breaks, or he gets tense and fast rather than relaxed. None of those is a reason to push on to a target time.
Keep a note of what you did and how he recovered. A simple per-horse log turns a vague sense that "he seemed fine" into a pattern you and your vet can read.
Safety for you. Stand at the center, keep the lunge line folded in loops you could drop and never wrapped around your hand (Mississippi State's handling guidance warns against coiling a rope around the hand), wear gloves, and keep the line off the ground where your feet can tangle in it.
FAQ
Is 20 minutes of lunging too long?
Nobody can tell you that honestly without knowing the horse, the circle size, the surface and the gaits. We found no study behind the 20-minute figure. Research shows that circles load the legs unevenly and sideways, and more so on hard ground, so short sessions on large circles are the cautious choice.
Is lunging bad for a horse's joints?
Circles create uneven and sideways forces on the legs that straight-line work does not, according to force-plate research, and a hard surface increases the sideways forces. That makes circle size, speed, surface and time the things to manage, and makes lunging a lame horse a bad idea.
How young can you lunge a horse?
We found no study that answers this for lunging specifically. Reviews of equine growth report that horses reach most measures of skeletal maturity by about two years and that free play supports bone development, but free play is not circle work. Ask your veterinarian about your horse.
How often should I lunge my horse?
As part of a mix that includes straight-line work and turnout, not as his only exercise. Let the purpose of each session and his recovery guide the frequency.
The short version
The number is a convention. The circle is the real issue. Go large, go slow, go both ways, choose soft footing, watch his recovery, and stop when he is going well.