Ever wondered how your eventer converts last night’s dinner into today’s performance? This is how he does it.
The horse’s body converts feed into energy storage molecules (glycogen, glucose and free fatty acids). During exercise, a horse’s muscles need ATP (adenosine triphosphate), in order to contract . There are two processes in the horse’s body, which produce ATP from these storage molecules:
- Aerobic metabolism
- Anaerobic metabolism
When the horse is working at a moderate pace (usually up to trotting speed in a fit horse), the aerobic pathway produces ATP for muscle contraction from glycogen, glucose and fatty acids. It uses oxygen which has been carried to the site of action by the blood. Harmless by-products are produced, which are excreted as the horse sweats.
When the horse needs to expend more energy than this by, for example, jumping at speed during the cross country phase, anaerobic metabolism takes over. Anaerobic metabolism doesn’t need oxygen and produces energy very fast, but in small amounts. The big disadvantage of the anaerobic pathway is the production of a by-product called lactic acid, which builds up in the muscle, causing the pH of the muscle to drop, producing fatigue and possibly contributing to the “tying up” syndrome. When a certain level of lactic acid in the muscle is reached, the pathway shuts down. Then, the fast muscle action cannot be maintained.
Usually, the horse travels at speeds which can be fuelled by the aerobic pathway. If fit, the anaerobic pathway should only be used for short intervals. So under normal circumstances, fatigue is more likely to result from the glycogen stores running out than from lactic acid build up. Towards the end of your cross country phase however, the horses heart rate increases, the rate of ATP utilization increases, and the “anaerobic threshold” is reached. This usually happens at a heart rate of about 140-150 beats per minute. At this stage, fatigue starts to set in.
Adequate starch and fat must be provided in the diet of an eventer. Starch is important, as it is one of the major factors in the synthesis of glycogen, although too much starch can cause metabolic problems.
Increased feeding of fats has recently been shown to have little beneficial effect on performance, contrary to a “fad” of fat supplementation a few years ago. Fat is an essential component of the horse’s diet, but large levels are not beneficial in any way.
Protein, although essential in the diet and useful in many ways, should not be fed in excess. This is because it is not an efficient energy source, it results in a need for increased water and potentially harmful breakdown products such as urea and nitrogen are produced.
One of the most important energy sources for the horse is fibre (provided by hay or grass). The horse’s hind gut is full of bacteria that ferment fibre. The fermentation process produces energy for a long time after the meal, making this a valuable source of energy for the horse during the event.
Besides these, there are nutrients that are missing or deficient in feed normally provided to horses. So if you are having stamina problems, it makes sense to feed a good supplement which provides these nutrients. A feed supplement designed for eventers should:
- help to delay the “anaerobic threshold”, thus prolonging the period of harmless aerobic ATP generation and delaying the onset of muscle fatigue.
- help to increase the stores of glycogen so that the store doesn’t run out during exercise
- help to optimise the oxygen-carrying capacity of the blood, so that sufficient oxygen is available for the aerobic pathway
- manage the situation of lactic acid build up and the resulting problems such as muscle fatigue, recovery, stiffness and “tying-up”
Some of the nutraceuticals that are believed to have these effects are:
- Thiamine (been found to help to decrease the lactic acid levels)
- Cyanocobalamine (could improve propionate conversion to glucose)
- Vitamin E (A study has found that vitamin E deficient horses show a quicker fatigue time during endurance exercise)
- Folic acid (Involved in the synthesis of haemoglobin, the blood’s oxygen carrier)
- Siberian Ginseng (A proven adaptogen with a glycogen sparing and ergogenic (increase endurance) action)
- Spirulina (Energy producing. Also provides amino acids for muscle building.)
- N,N-dimethylglycine (Aids recovery, possibly ergogenic)
- MSM (Helps recovery by decreasing stiffness and inflammation)
- Selenium (Known to be effective in decreasing the incidence of “tying-up” or azoturia)
It is important to note that these ingredients are nutrients, not drugs. They are not going to give anyone an unfair advantage. They are just going to ensure a horse capable of performing to the best of its ability.
Beryl Shuttleworth, The Herbal Horse, +27 83 437 1814, firstname.lastname@example.org, www.theherbalhorse.co.uk