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We Are Flying Solo

October 14, 2014

Throwback...Tuesday: Rocket Fuel & Other Stories

A brain belonging to eventer79 has left the building.  If found, please return to your nearest Missing Blogger Station immediately.  

To fill the static-y void in the meantime, I have brushed the dust off our miniseries on equine nutrition (which you can access in full under the handy Education menu) for new readers.  Ummm, new as in "what, you haven't been reading my riveting brain-dribbles for the past four years straight?!"  

So I have been reading about nutrition (the horse's, not mine, who cares about that?).  Why?  Well, because I don't want to do the actual work I am SUPPOSED to do, so why not. And if it has the word "horse" in it, then it is a pre-ordained given that I must read it. Who am I to argue with those that ordain??

Lots of interesting things to share with you. How horses use their feed, what different types of feed items offer, and what magical food will make your horse grow a unicorn horn (calm down, BFF, one of these items may or may not be fictional). 

Those of us who grew up obsessed with horses learned many important horse-keeping rules that have been passed down through generations.  One of those things that I always heard was that you never worked your horse hard right after he ate. Much like nagging Aunt Margaret told you never to swim right after you ate or else you'd surely get a cramp & drown. I always held equal skepticism for both. Turns out, I was partly justified.

Wait, So I Will Not Kill My Horse By Riding Him After Dinner?

After your horse eats, his body begins to metabolize his food. This means that his blood insulin will spike, which reduces the efficiency with which the body burns fat (fat is generally the go-to energy resource for horses). So, if they need energy when insulin levels are high, their bodies will instead turn to stored glycogen reserves first. While this is hardly deadly, glycogen is something you want to save until you really need it (I'll explore why in the next post).

Psh, can eat AND work...
So, what's a rider to do? Well, you have two choices. It takes about four hours for that insulin spike to return to baseline. So you can (a) wait four hours (Suck! Who wants to do that?!) or (b) ride immediately. That's right, the spike doesn't really get up there for about two hours, so if you hop on within thirty minutes, you can have your ride & then put Dobbin away before he has to switch over from fat metabolism. What you want to try to avoid, for maximum energy accessibility & efficiency, is hitting it right on that two hour mark, when insulin levels are highest & burning fat is the most difficult.

Now, obviously, we're not going to get this right every single ride, but it's something to shoot for as a general trend & a handy bit of info you can toss out if someone gives you crap for riding your horse right after he ate.

Scorecard: Science, 1, Anecdotes, 0!


  1. Hmm makes sense, racehorses eat and then train and never seem to have an issue. Love me some chemistry cat!

  2. So I always understood it as a difference between forage and calorie-dense food like grain. I have zero problem pulling a horse off hay or grass to work them, or letting them snack in between working (unless they're so hot that standing would do harm, and I want them walking). But I do generally avoid riding within an hour of getting grained, especially if a) they're going to work hard or b) they get a lot of grain. If a horse gets 2 quarts of grain and then immediately does gallop sets, that's not going to sit well. I think of how uncomfortable I'd be if I had a full dinner and then jogged for an hour afterwards.

  3. In all things (even science!), there is no black & white, but one aspect we must always be careful of is equating the horse & human. Their physiology is so very different in so many ways. In addition, we are generally always warming up the horse before asking him to do strenuous work, so we aren't asking him to go zero to 60 in five minutes (I hope!).

    Amanda, you are correct that we do not want to stuff the horse with a huge meal of carbohydrates & expect him to perform at his peak, say at a competition, immediately. However, you do not want to skip a meal either, as this can increase ulcer risk, among other issues.

    But for your average schooling session, to avoid insulin effects on energy production, it is best to begin your ride within 30 minutes of a normal meal (we have to groom & tack anyway). The worst timeline is that 2-hour mark. If a horse has the ability to get fed multiple smaller meals during the day, that is an excellent strategy as well.

    And just to caveat that I'm not asking you to take my word for it carte blanche -- these data are the result of studies performed (among others) by the EXTREMELY knowledgeable & thorough team at KY Equine Research ( We've learned so much, but if I got excited & tried to encapsulate it all, the post would be so long, the interwebz would reject it!

  4. This is actually quite similar to human physiology. Fat storage is the most stable energy source in humans also. Where glycogen is the 'fast' energy source, used in fight, flight or freeze sympathetic nervous system situations. Thanks for the informative post.

  5. Amy, yep, that part is similar. Differences arise in other details though, such as protein, which in horses doesn't provide much of an energy boost like it does in humans & is very inefficient for energy production. The same is true for other human "energy production" supplements; they were developed for human use & equines & humans don't have the same limitation points. Equines are also MUCH more efficient at producing energy than we are. So increasing protein in equine diets is done at much lower proportions than increasing, say fat.

    Eeee, I love geek-out sessions, thanks for your comments!

  6. Ha - milk² and mouse divided by cheese wedge... chemistry cat rules.

    Don't know how scientific it is, but my hungry hungry hippo goes into a bit of a food coma right after meals, so I generally ride before or halfway between. Might not be giving him the stomach cramps, but it puts a cramp in his style... ;D

  7. ROFL, CFS, I didn't even notice the stuff on the chalkboard, that's awesome!!

    I am certainly no stranger to food coma...meetings after lunch are terrible!

  8. Well that stinks. I have probably ridden my horse at the two hour mark plenty of times when I went for morning rides in the summer.

    Are you not concerned about the muscles competing with the gut for oxygenated blood during exercise right after grain? Or perhaps this is why the muscles must switch to anaerobic respiration. The gut wins.

  9. Val, I wouldn't beat yourself up too much -- the takeaway point is the understanding of the basic metabolic timeline to inform prioritization. The largest impact of a lower metabolic efficiency when the horse is asked for peak performance, i.e. run a XC course, sprint-work, etc, and is obviously much higher at high levels of sport/effort.

    Again, shades of grey: if his insulin levels are higher, he will, in most cases, simply tire more quickly, either because he just can't produce enough energy or because he must switch to burning glycogen sooner, of which there are small stores. Neither is particularly damaging to the average horse for short periods of time. Fat & glycogen can be replenished & despite what some horses insist, tired muscles are not immediately fatal!

    Your question about oxygenated blood is a good one. The scientist in me cannot give a detailed answer without spending some time doing some research (& I don't think I'm any better at Google than you are). Horses have a LOT of blood (varies by breed & weight, but avg 1200 lb horse has ~12 gallons) & MASSIVE lungs. So there is a great deal of oxygenated blood to go around. Their physiology is also far more efficiently designed than ours when it comes to powering muscles.

    So without letting myself get sucked into reading a zillion articles (ahhhh, I'm so bad at resisting temptation!), I would have a low concern on that one, as there is a lot to go around. A small proportion of glycogen/carbs are used at all levels of work, but at lower/slower levels, energy production is dominated by fat catabolism. Both this process & the shift to increased anaerobic activity when needed are regulated by epinephrine, which is released at the start of any exercise. More intense exercise and/or increased fatigue = more epinephrine (adrenaline) = increased need for energy production at a rate fat stores cannot provide = anaerobic metabolism.

    The metabolic limitation is generally the speed of the catabolic process. So even with an infinite amount of oxygen, aerobic respiration still has a maximum speed with which it can supply the body with energy. THAT speed, however, you CAN increase with conditioning.

    Clear as mud?