Let’s talk about heat exhaustion – a serious consequence of exposure to high temperatures and intense physical activity. We'll explore the physiological processes and biochemical pathways that contribute to this condition and discuss herbal preventatives, including the importance of electrolytes. But first, let’s identify its signs and symptoms.

Signs and symptoms of heat exhaustion

Heat exhaustion is characterised by various symptoms, including:

• Profuse sweating.
• Weakness or fatigue.
• Increased heart rate.
• Increased respiratory rate.
• Decreased pulse pressure.
• Decreased jugular refill.
• Pale to white mucous membranes.
• Cool extremities (distal limbs and ears).
• Low blood pressure if your horse gets up from lying down.
• Muscle cramps.
• Dark-coloured urine.

The biochemical pathways involved in heat exhaustion

Understanding the biochemistry behind heat exhaustion involves understanding the body’s thermoregulatory processes. The body meticulously maintains a balance, called homeostasis, where heat production equals heat loss. Disruption of this equilibrium can lead to heat exhaustion.

• Thermoregulation and dehydration - When the body’s temperature rises due to external heat or physical exertion, the hypothalamus – the body’s thermostat – springs into action, prompting sweating as a means of cooling. Sweat, composed of water, sodium, and other electrolytes, serves as a cooling agent – it’s why the far-east diet is full of chilli, to make you sweat! 😉. However, when sweating is excessive and not matched with proper fluid and electrolyte intake, dehydration can set in.

• Impact on cells - Dehydration may provoke hypovolemia (low blood volume), tampering with nutrient and oxygen delivery to cells. Consequently, cells convert from aerobic (oxygen-dependent) to anaerobic (non-oxygen-dependent), producing lactic-acid and other metabolites that can disturb cellular function.

• Stress proteins - Furthermore, heat stress can trigger the expression of heat shock proteins (HSPs). These proteins, commonly called stress proteins, work hard to minimise damage by binding to other proteins, ensuring accurate folding and function. However, prolonged heat stress can overwhelm this protection, causing protein damage and cell death.

Causes of heat exhaustion

While heat exhaustion often stems from a mix of intense physical activity and high temperatures, other factors can also play a part:

• High humidity, hindering sweat evaporation – a key body cooling mechanism.
• Dehydration, undermining the body’s cooling capacity.
• Rugs! How many times have we all seen a pony stuck in the middle of a field with no shade on a hot day – with a flipping rug on?
• Specific medical conditions, i.e. heart, lung, or kidney issues.

The role of electrolytes and preventing dehydration

Electrolytes – i.e. sodium, potassium, calcium, and magnesium, are essential minerals that carry an electric charge. These minerals conduct electrical impulses, facilitating vital processes such as muscle contractions, nerve signalling, and maintaining fluid balance in the body.

Replenishing electrolytes is crucial during heat exhaustion, as they are not only lost via sweating but are also essential for sustaining proper hydration and preventing dehydration.

NB. We sell pure, unrefined, unpolluted, coarse sea salt, certified by the Soil Association, available in bulk at seriously good prices compared to the supermarkets from just £12.00/kg.

Homemade electrolyte solution

Whip up a simple yet effective electrolyte solution at home for you horse (and us humans too):

1. 1-litre water
2. ½ teaspoon salt
3. 6-teaspoons sugar in a water bottle or resealable container.
4. Shake well until salt and sugar are completely dissolved.

I know, I know, sugar for horses is the devil’s food, but sugars form an integral part of the sodium-glucose cotransport mechanism - and remember, this is for necessary hydration, not everyday use. This biological process is how the body absorbs water.

In simple terms, glucose and sodium are absorbed together in the gut. The presence of glucose facilitates the absorption of sodium, which in turn pulls water into the bloodstream. Which means … sugars in rehydration drinks significantly enhance the absorption rate of water and electrolytes, helping to accelerate recovery from dehydration.
 
Top tip – For a great way to avoid the bleached supermarket sugars, head to your local health food shop, or hop online, and get some Coconut Sugar. Pure, natural, and a whole lot less loaded with unhealthy sugar.

If you're making this solution up for yourself, a hands-up from me - from a human perspective I personally don’t enjoy the taste of electrolyte solutions. I prefer licking a big pinch of salt off my hand and chasing it with fruit juice. Not exactly precise, and I wouldn’t recommend it for any human that’s acutely dehydrated, but it’s effective for prevention if/when needed.

Hydration superstars - mineral-rich herbal infusions

Rehydrate your horse with mineral-rich herbal infusions which can help prevent heat exhaustion during summer. These herbs are packed with vitamins and minerals, including electrolytes, improving hydration levels and providing a nutritional boost.

I like to infuse them in my horses' feedbowl soak water, then slosh the lot in (soggy herbs and all) into the feedbowl.

• Mint - Mint cools! It's a natural menthol coolant, with a high content of calcium, potassium, and magnesium; either peppermint or spearmint infusions are wonderful hydration aids.
• Raspberry leaf - Rich in minerals including magnesium and potassium, raspberry leaf is a revitalising and cooling tea that can help with muscle cramps.
• Lemon balm - An excellent source of potassium, lemon balm is a horse favourite with a hint of citrus and a soothing flavour, and its gentle nervine properties will help to ease anxiety and promote relaxation.

Top tip - as above, remember, when using herbal infusions for hydration it’s important to sweeten them.

Supporting and prevention of heat exhaustion

If your horse is struggling, initiate the following immediately:

• Obvious I know – find cool shade.
• Hydrate – water of course, and if you can’t get your hands on an immediate electrolyte supply, make up the homemade electrolyte solution above.
• Cool down - a cool hosedown (always start at the hooves and slowly work your way up the body), or use damp towels to lower body temperature.

Prevention is far better than cure

Practice perfect prevention – again all obvious stuff but all useful strategies:

• Ensure your horse is well-hydrated.
• Avoid intense activities during the hottest part of the day.
• Take periodic breaks if active on hot days.
• Incorporate mineral-rich herbal infusions (as mentioned above) into your hydration strategy to maintain your horse's electrolyte balance.

Keep in mind that heat exhaustion can quickly advance to something more serious, so if symptoms persist or intensify, never hesitate to call your vet.

Conclusion

Understanding the intricacies of heat exhaustion is vital. These simple prevention techniques are easy to apply so we’re better prepared for summer. Stay cool, stay hydrated, and have a fantastic summer with beloved Ned! 😉