Cold Weather and Your Horse's Lungs

Cold weather and your horse’s lungs – when is it too cold to ride?

If you are a meteorologist, you know that any temperature below 40° F is considered cold. If you are me, anything below about 85° F is cold. None of this really matters, except when the actual temps are so cold that they affect your horse’s lungs, and not in a good way.

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Turnout is still important in cold weather if the footing is safe.

How cold weather affects your horse’s lungs and body:

It’s a long way from your horse’s nose to his lungs. During that trip, his respiratory system conditions the inspired air. Warmth and humidity are added so that when his breath hits the lungs, the lung’s parenchyma isn’t damaged. The parenchyma is any part of an organ that carries out major functions. In the case of lungs, the parenchyma consists of alveoli, ducts, bronchioles, and serves to exchange gases. This is how your horse’s body gets oxygen and expels carbon dioxide.

When the weather is cold, a few things happen to your horse’s lungs. There’s a lot of air passing through your horse, and he’s not able to warm and humidify it properly. The respiratory system of your horse contains a mucosal lining, which is damaged during exercise due to the unconditioned air. Additionally, it’s believed that breathing dry, cold air contributes to inflammation and possibly the development of asthma.

This is documented in the development of “skier’s asthma”, which is essentially cold weather-induced asthma seen in cross country skiers. The tissue damage caused by inhalation of cold air causes airway obstruction congruent with asthma.

Most of the science tells us that vigorous exercise is what causes these events, so on extra cold days, perhaps a brisk walk is all you need to do with your horse.

There’s not much that stops me from exercising my horse. In really cold weather, we amble along, no pressure, no trotting or cantering.

What’s the science behind cold weather lung health?

In horses, we can thank OSU for some cold weather research during the mid-2000s. A group of racehorses served as the subjects and were asked to exercise while breathing air that was cooled to about 40° F.

What did they find?

Horses that breathed cold and dry air during exercise for the study showed changes to their cytokine profile in their airways. Translation – Cytokines are a group of proteins that are made by horses, and people and other creatures, too. They serve to communicate between cells and are heavily involved in the immune functions of creatures. This increase in cytokine activity of this study indicates that cold-weather exercise might influence a horse’s immune response, and not in a positive way.

Previous studies have found similar results. Interestingly enough, similar studies have been done in sled dogs. Some dogs from these studies take months for their lung health to return back to normal.

Yet more studies (three of them, in fact!) have found that air at 23° F a horse’s lungs will be damaged. This next statement isn’t science – but instead personal observation. I don’t want to exercise at 23°, it just burns my lungs! Should you draw a line in the sand about 23° F? Probably not. It’s just good place to start.

These same studies found damage to the lower lungs two days after exercise.

What hasn’t been studied is if horses can acclimatize to exercise in cold weather. It’s suspected that they can, especially for horses that are fit, live outside, and are regularly exercised. But that’s the best guess.

This particular hooligan loves to run amok in the paddocks in the freezing cold. But it’s his decision to do so.

What about the rest of your horse? Like his heart and joints?

Your horse’s heart can work harder in cold weather! Your horse’s heart rate and blood pressure will increase to help keep him warm. The circulatory system also starts to concentrate it’s effort into your horse’s core – meaning that legs and vessels near the skin receive less blood. This is part of the mechanism that can lead to frostbite and tissue death in horses. Frostbite is usually seen on ear tips, but it can happen elsewhere.

A horse’s heart rate is also a measure of his fitness, so you can measure his resting heart rate and compare it to his heart rate during and after exercise to notice how high it becomes. You should also be measuring how rapidly it returns to normal.

All of this requires more calories. Most horses add a bit of extra insulating fat in the winter, which is normal and helps your horse stay warm. Exercise in the winter also used up to 5X the amount of energy as warm weather, which means your horse might be going through his calories and glycogen energy packs much quicker than in the summer. After these are gone, an exercising horse will start to convert fat into his oomph. This isn’t efficient, and it means your horse may need some extra calories in cold weather to stay at weight. Other horses have no issues holding onto some extra pounds, so monitor your horse’s weight with a tape to keep him on track.

Muscles are also affected by cold weather, requiring a longer warm-up in the winter. I think most of us can agree it’s the same feelings that we have when exercising in the winter. There’s also any arthritis in joints to consider. While arthritis makes moving more uncomfortable, moving is necessary to stave off the stiffness.

Beware of snowballs in the cold weather.

What other cold-weather things do you need to consider before riding your horse?

The dang footing! Frozen ground pounds your horse’s legs and hooves. Frozen hoof prints and ruts and other natural topography can create unforgiving trip hazards. Ice is perhaps the most dangerous of all and should be avoided at all costs. Snow, while utterly romantic to ride in, can also be slippery, icy underneath, and create lots of leg twisting snowballs in hooves. Or you can get all of the romance.

How healthy and fit is your horse? I hope it’s logical that an older, injured, or out of shape horse needs more warm-up, less strenuous exercise, and shorter sessions during colder weather. On particularly blustery days, go for a hand walk so that you both can pump some blood around your bodies!

Can you dedicate a lot of time to cooling out as well? Sure the warm-up is important to get your horse limber and warm. Plan on devoting just as much time for your horse to get his body temperature back to normal after a ride. Coolers and a good rub down will certainly help.

I really enjoy the snow at the barn, especially when it’s just deep enough to cover all of the ground.

How to help your horse in the cold weather:

Start with his normal vital signs. Start to take his temp, pulse, and respiration at rest and during/after exercise so you can notice trends.

Keep his body limber and moving to give arthritis and cold muscles a run for their money. Use fancy coolers if you want to. Use ordinary coolers if you want. Don’t skimp on turnouts and extra-long walks.

Decide how much work your horse needs to do in the cold weather. There’s a lot of fitness to be had at the walk if the air temp is freezing.

Keep the dust to a minimum where possible. We know that cold weather irritates lungs, we don’t need to add dust in the mix. Resist any and all urges to lock your horse in the barn with closed windows and doors. Wet down foods, use low dust bedding, clean the stalls and sweep the aisles when the horses are not in the barn. Dust rafters, keep the cobwebs at bay, steam your horse’s hay, and notice how your horse breathes.

Hydration and calories are key! Wet hay is still delicious. Horses will drink more water when it’s warm. Sloppy meals for your horse are fun to make and mostly fun to clean up.

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Mercury-Free Veterinary Thermometer. Glass with Cord and Tail Clip

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