In an earlier article, I wrote about the window of tolerance, which is kind of like the horse’s emotional comfort zone.

In this article, I discuss how you can grow your horse’s individual window of tolerance so they can become more resilient to the demands we impose. I also introduce the concepts of pendulation and titration whilst revisiting self-regulation.

When your horse is in their window of tolerance, they can fulfil all kinds of important physiological processes such as resting and digesting. They can also perform cognitive processes such as thinking, processing information and learning. Here, the horse is described as being in an aroused nervous system state.

The term ‘arousal’ does not refer to excessive energies or emotions – it just means the horse is not asleep. Arousal is associated with the parasympathetic nervous system.

When the horse is pushed over the threshold of their window of tolerance, their nervous system is described as activated, engaging the more primal sympathetic nervous system, typically seen in flight, flight or fawn (freeze) responses. See Draaisma’s Communication Ladder on ‘Fight or Flight’ linked at the end of this article.

The window of tolerance is clearly the best place for a horse to be – not just because they are happiest and healthiest there but because they are going to be the easiest and safest for us to interact with. They are also more likely to grow their window of tolerance and develop a calm nervous system.

For example, a positive state of relaxation will allow the back to swing and the mind to relax. The horse will develop mental and physical attributes that make them more capable of responding to the demands of interacting with humans.

This does not mean that a horse will not spook or startle whilst they are in the relaxed state of their window of tolerance. Everyone is entitled to be caught off guard. What it does mean, however, is that a horse in their window of tolerance can easily accommodate ‘surprises’. Most surprises will cause a reaction without pushing the horse out of its window of tolerance. They may push the horse towards its threshold but they can be easily accommodated because the horse was not already stressed, pressured or responding to other stimuli.

In moments of activation, the horse may react by quickening their steps, rushing forwards, raising their head and neck, hollowing the back, raising the tail, quickening or holding their breath or spinning to see something.

These responses may be followed by relaxation, head shaking, body shaking or a deep breath as the horse’s nervous system changes from an activated state (over threshold) back to an aroused state within their window of tolerance. .

Identifying visible signs of relaxation like the ones above is important because an absence of visible signs of tension does not necessarily indicate relaxation.

In my previous article, I discussed how the window of tolerance is dynamic.

The window you met yesterday with your horse may not be the window you meet today. The cat that your horse could accommodate jumping into their window of tolerance yesterday may not be able to fit today, given that your horse’s window is already full of other stimuli; the weather, pain, a change in diet, unfamiliar sights, sounds or smells, hormonal changes or the removal of a paddock mate, for example.

You are unlikely to notice that your horse is already dealing with those things until the stimulus stack gets too great to bear and the cat becomes the last straw that pushes your horse over threshold.

That is how your horse’s behaviour might seem to be unwarranted, out of character, unnecessary, etc. In reality, they were doing such a good job of coping that you didn’t notice.

How to help your horse

Your horse’s nervous system is going through cycles of activation and relaxation/deactivation all the time. When these cycles and flows fit in the horse’s window of tolerance, you might not even notice all the work that is going on under the surface. So, when your horse ‘loses it’, you have the choice of being completely annoyed or congratulating them for having coped so well with all the stimuli that came before their ‘final straw’.

Riders find it easy to notice when a horse’s window of tolerance can’t accommodate the stimuli with which they are faced (when they just aren’t coping). But your response when your horse crosses their threshold, can either grow or shrink their baseline window of tolerance and its resilience – it’s ability to stretch and bounce back quickly. Yes, that means you can grow your horse’s window of tolerance!

There are three concepts to help you help your horse; pendulation, titration and self-regulation.


Pendulation is a general term for something which swings, like the weight hanging on a pendulum clock. You might experience your body pendulating slightly forwards and back as you breathe.

Peter Levine uses the term pendulation to refer to a full cycle of the nervous system going from arousal to activation and then back to arousal.

This can be imagined as wave formation tracking high and low on a heart monitor, but you can also think of it as a process of expansion and contraction.

Incorporating pendulation into your relations with horses means being patient. It is not good enough for the horse to ‘calm’ down somewhat or be close to a state of relaxation. It means allowing for a full and complete release, deactivation or expansion.

I have heard cowboys talking about how in times gone by, horse trainers would stop and have a cigarette whilst they let the horse “do some thinking”. The time it took to have a cigarette (maybe roll it too) probably provided some time for the horse’s nervous system to pendulate and reset to a calm state of arousal within the horse’s window of tolerance.

Every single time you allow for a full pendulation of the nervous system, you are growing the window of tolerance.

It is important that you avoid stimulus stacking (refer to the previous article). That means do not introduce another stimulus or request until the horse’s nervous system has reset to a state of arousal. Often, when we try to control our horse’s reactions, we are inadvertently adding more stimuli. Instead of helping them to move through different nervous system states, we can contribute to them getting stuck in extremes of hyperarousal (or hypoarousal expressed in learned helpless).

Now, this advice about pendulation should never be interpreted to mean that you should leave your horse to deal with disorder and fear for themselves.

For example, you should not leave a horse to run around a paddock in separation anxiety until they learn to live by themselves (if they do, then it will be by a process of learned helplessness, not confidence). Nor does this mean that you should let a horse gallop around on the lunge line until they are exhausted.

In fact, the better you become at reading your horse’s nervous system response, allowing for pendulation and avoiding stimulus stacking, the less likely your horse is to reach and get stuck in such extreme nervous system responses.

For example, you might notice that Horse A’s separation anxiety starts as soon as you lead their mate Horse B out of their paddock. Maybe they don’t appear to get anxious until you are 10 or 20 metres away from the paddock.

By asking Horse A to stand until Horse B’s anxious behaviour wanes and then ceases (a full pendulation), you are helping to grow Horse A’s window of tolerance, which is the same as saying that you are building Horse A’s resilience to being left behind.

With the example of lungeing, having noticed that your horse takes off as soon as you feed out a loop of the lunge rein, you might just stand and observe how the horse’s anticipation of lungeing stimulates their nervous system and triggers their body to adopt the flight posture associated with hyperarousal.

Without interfering or stimulus stacking, you may then witness a pendulation as the horse releases a breath, shakes their neck and relaxes the topline and tail. What you are properly witnessing is a moment of growth and learning as the window of tolerance grows and expands.

What next? This is where you will need to draw from another tool, titration.


Titration is a process used in chemistry to add the tiniest drop of one solution to another – one insignificant amount at a time.

Figuratively speaking, titration is the opposite of dropping horses in the deep end and expecting them to swim.

In behaviourism, that would be called ‘flooding’ and could result in the horse’s nervous system being so overwhelmed that they may enter a state of learned helplessness, which is neither healthy for horses nor safe for their humans.

In the case of Horse A who suffers separation anxiety, titration would entail thinking about the smallest, tiniest thing that starts an anxiety response and then very slowly titrating Horse B’s movement away from Horse A, one step at a time allowing for pendulation in between.

In the case of lungeing the horse that takes off as soon as they feel slack in the lunge rein, titration might start with letting out a single centimetre of rein. However, as you become more attuned to reading your horse’s nervous system from their body language, you might realise that you need to titrate the process of walking towards the round yard, allowing for pendulation to occur and making sure there is no stimulus stacking.

After continued practice, you may note that the slightest distraction which used to send your horse skidding off around you as you prepared to lunge now just becomes something that draws their attention for a few seconds before it is dismissed (ie. quick deactivation instead of escalation).

This is where pendulation and titration will have enabled the window of tolerance to grow and your horse to build resilience and self-confidence.


Allowing for pendulation and enacting titration for your horse requires that we as riders and handlers are self-regulated.

As described in the previous magazine article, nervous systems respond to one another and they are safety-seeking. Always try to be the kind of nervous system that your horse can use for co-regulation to help them return to and grow their window of tolerance.

Seeing as horses and humans are both mammals, it is not surprising that pendulation and titration are important for us to practice ourselves.

If we are nervous about leading or lungeing an anxious horse, it will be hard for us to consistently create the conditions for pendulation and titration. More importantly, it will be hard for us to self-regulate our own emotions and nervous system state.

That being said, there is no reason why you can’t use a process of titration and allow your own nervous system to pendulate, grow and expand. You might choose to do so before you enter the paddock to catch Horse A, after you close the gate behind Horse B, before you feed out the slack of the lunge rein or even when you stand at the mounting block.

The more you become aware of and respect your own nervous system, the more you will be able to help your horse.

Further information:

The Window of Tolerance, published in the March-April edition of Horses and People magazine


Search the internet for books by Peter Levine.

This article appeared in the May-June 2020 issue of Horses and People Magazine