The role of exercise in increasing insulin sensitivity in the horse.
Exercise benefits a horse in several ways. The effort of movement increases the calories a horse utilizes each day. The more calories a horse uses to fuel exercise, the fewer calories are available to be converted into unwanted weight gain. The combination of exercise and a properly balanced restricted diet can result in weight loss that benefits a horse with insulin dysregulation. Exercise of a high enough intensity increases the cells’ sensitivity to the hormone insulin, allowing each cell to properly absorb circulating blood glucose.
The research shows that exercise can impact insulin sensitivity.
Some of the earliest studies showed 10 minutes of exercise 5 times a week for 6 weeks increased sensitivity in ponies that were also on a diet that controlled feed intake.
A 2011 study in Brazil looked at varying levels of exercise, from turnout only to moderate exercise multiple days per week. Turnout alone was insufficient in increasing insulin sensitivity. Light exercise composed of walking for 60 minutes with short intervals of trotting or cantering, increased sensitivity more than turn out alone. Moderate exercise composed of 90 minutes of mostly trotting with some walking and cantering was the most effective at increasing insulin sensitivity. Exercising 5 days a week was better than exercising 3 days a week.
The most recent consensus is that a horse needs significant exercise to make a difference when insulin dysregulation is present. Recommendations range from 30 to 40 minutes of moderate exercise per day, 5 days per week.
The definition of moderate exercise varies. One source defines it as 30 minutes of cantering 5 days per week, another defines it as 3-5 hours per week of a combination of 30% walk, 55% trot, 10% canter, 5% low jumping, cutting, etc. One researcher stated, “the horse should work hard enough to sweat 5 days out of the week.”
It is important to note that studies also revealed horses on restricted diets combined with low levels of exercise showed more improvement in insulin sensitivity than those managed on only a restricted diet.
How much exercise is enough?
How much exercise your horse can do will depend on how sound they are, what your footing is like and how much time you have to work with your horse. The main take-away message is restricted diet alone does not always allow you to manage insulin dysregulation. Any level of exercise is better than no exercise at all. More exercise is better than less if your horse is sound enough to handle it and you have the time to provide it.
If your horse is sound, start exercising 2-3 times a week for 20-30 minutes and gradually work up to 5 times a week.
If your horse is suffering from laminitis, it is important to limit possible damage to the sensitive laminae caused by too much exercise on the wrong surfaces. Work with your veterinarian and farrier to devise the safest routine for your horse.