Easing horses into exercise in colder weather will help them stay injury-free and perform at their peak, explains Dr Susanna Ballinger MRCVS, who investigates the biology behind warming up and how to provide the best post-workout care, too
Warming up before work is important year-round, whatever the weather, and in simple terms it raises the horse’s body temperature to allow safe, injury-free exercise.
In winter, when shorter daylight hours can restrict riding time, it may be tempting to condense this vital phase.
Yet a combination of colder weather and longer periods of stabling, often with little or no field turnout, means that many horses require more careful preparation at this time of year.
How exactly does a warm-up ready a horse for harder work?
When movement commences, muscles contract. Chemical energy converts to mechanical energy for this contraction, which in turn causes an increase in muscle temperature. Heat then dissipates throughout the body and the horse’s overall temperature rises.
As a result of rising body temperature, blood vessels widen – a process known as vasodilation – to facilitate an increase in blood flow to all organs, including muscles. A higher rate of blood flow also increases oxygen delivery to muscles, promoting aerobic metabolism.
If there is insufficient oxygen in the blood to allow muscles to produce energy to exercise aerobically, anaerobic metabolism kicks in. This leads to a potential build-up of lactic acid which causes fatigue, muscle damage and, in severe cases, rhabdomyolysis, or “tying up”.
Oxygen is carried in red blood cells, up to a third of which are stored in the horse’s spleen. At the start of exercise, during a controlled warm-up programme, the spleen releases these into general circulation. This “splurge” of red cells increases the oxygen-carrying capacity of the blood, preparing the horse for exercise by ensuring a greater supply of oxygen to all organs and muscles.
As the warm-up intensifies, the rising heart rate increases blood flow around the whole body. The increased body temperature improves elasticity within tissues, including muscles, ligaments and tendons. This flexibility allows more efficient contractility, the ability of muscle to shorten, helping prevent injury.
Warming up also promotes a steadily increased airflow into the lungs. Inhalation of cold air can cause irritation and constriction of the airways, leading to respiratory problems including coughing. This is particularly evident in horses with pre-existing respiratory conditions. While you cannot warm the air as it enters the lungs, starting slowly and gradually increasing the intensity of the programme reduces the likelihood of a problem arising.
An established warm-up routine used at home and prior to competition will prepare athletes – both human and equine – mentally, for the work ahead.
Stepping it up
There are two warm-up phases:
• Passive warm-up is more relevant in colder weather and involves increasing the
horse’s body temperature by external means, with rugs and heat pads, or by using a solarium. This warms the muscles, but usually only along the topline and back.
A massage pad will boost blood flow but only to the area of application, with a small increase in temperature in the muscles being massaged.
Unclipped horses with a thick haircoat over their quarters should not need an exercise rug during warm-up, even in colder weather. If they are clipped out, however, keep their muscles warm, ideally with a well-fitting exercise rug of an appropriate weight for the climatic conditions. Remove the rug once the horse is warmed up to prevent the detrimental effects of increased sweating.
• Active warm-up in colder weather should start with a generalised session which includes initial walking exercise, progressing to a period of controlled, faster (trotting or cantering) exercise. The overall warm-up duration will depend on the planned activity, the horse’s fitness level and the external temperature.
At least 10 minutes of walk is usually recommended. If the horse is older, arthritic and stiff, or has had a previous injury, it may be prudent to walk for longer, gradually introducing bending and stretching before increasing the intensity of work.
This should be a relaxed phase with the horse moving forwards freely in a manner it is comfortable with, ideally in a long and low posture. As the warm-up period progresses and, if appropriate for the individual, flexing and stretching within the walk can be included.
Monitor the horse’s respiratory and heart rate during this time to ensure that you are not stepping up the work too quickly.
Walking can be undertaken on a horse-walker or treadmill, in-hand or ridden. The risk with lungeing is that the horse will have a hooley and set off at canter, rather than walk, potentially sustaining injury by using muscles before they have warmed up sufficiently.
With the walking completed, five to 10 minutes of trot or slow canter exercise can commence.
The horse should be comfortable in the pace chosen; some find trot more difficult
than canter, but both paces will achieve the desired physiological changes of increased body temperature.
Finish with a short period of activity-specific exercise. This may involve some gymnastic jumping work over small fences, beginning to bend and flex in a collected form for dressage, or a gradual increase in faster work if galloping is intended. The horse should now be ready for work.
Be prepared to tailor or adapt your warm-up for the individual and the weather conditions. Remember, too, that a horse’s management routine will affect its ability to cope with exercise in the season ahead.
Forage will help maintain body temperature, especially in colder weather as it is used to generate body heat, so provide a plentiful supply.
Hydration is also key to performance and recovery, yet most horses have reduced turnout and less access to moisture-rich grass in winter. Encourage a horse to drink by taking the chill off the water, and consider feeding haylage as it has a higher moisture content than dry hay.
Build time into your session for a cool down. Controlled walking not only promotes physical cooling and a decrease in heart and respiratory rates, but maintains circulation to remove lactic acid from the muscles.
Cool a hot, sweaty horse by walking it for 10 to 15 minutes post-training, until its skin has dried and its nostrils have stopped flaring. Use a sweat sheet or exercise rug in cold weather for this phase, just as you would put on an extra layer immediately after your own exercise session.
After cooling, a horse should be washed down with warm water and either rugged appropriately or stood under heat lamps or in a solarium to prevent chilling. Replace the regular rugs only once the horse is completely dry.
About the vet, Dr Susanna Ballinger
Susanna is an RCVS advanced practitioner in equine practice and clinical director at Ballinger Equine, the award-winning first-opinion ambulatory equine practice. Providing 24/7,365-day veterinary care and top-quality diagnostic imaging in the field throughout eastern England. Ballinger Equine also undertakes pre-purchase examinations across the UK and Europe.
Ref: Horse & Hound; 19 November 2020
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