Understanding seizure threshold

Every brain — healthy or epileptic — has a seizure threshold: the level of neurological excitability at which a seizure is triggered. In pets with epilepsy, this threshold is already lower than in a healthy animal. Environmental factors can temporarily lower it further — making a seizure more likely — or help maintain it. Understanding this concept helps explain why seizures sometimes seem to cluster around stressful events, sleep disruptions, or periods of intense physical activity.

Stress and anxiety

Stress is one of the most consistently reported anecdotal seizure triggers among owners of epileptic pets, and there is biological plausibility to this association. Cortisol (the primary stress hormone) and other stress-related neurochemical changes may lower seizure threshold in some pets. Published owner surveys have reported that stress is among the most frequently identified perceived seizure triggers.

Practical approaches to reducing stress

• Maintain routine — Consistent feeding times, walk schedules, and sleep environments reduce baseline anxiety
• Gradual introductions — New pets, people, or environments should be introduced slowly when possible
• Safe spaces — Provide a quiet, comfortable retreat area where your pet can decompress
• Noise management — Thunderstorms, fireworks, and loud events are significant stressors for many pets; discuss management strategies with your vet if your pet is sensitive
• Boarding and travel — Plan carefully; discuss anxiolytic options with your vet before high-stress events (see Guide 23 for more on travel with an epileptic pet)

Sleep disruption

Sleep deprivation is a well-known seizure trigger in human epilepsy, and nocturnal seizures are common in veterinary patients. Some dogs with idiopathic epilepsy experience seizures predominantly or exclusively during sleep or in the period just after waking. Maintaining consistent, adequate sleep opportunities — and avoiding disruptions to established routines — is a reasonable supportive measure.

If your pet is experiencing nocturnal seizures, inform your veterinarian. This pattern is clinically relevant and may influence treatment decisions.

Overexertion and heat

Intense physical exertion and overheating may lower seizure threshold in some epileptic animals. This does not mean epileptic pets should be sedentary — regular, moderate exercise is beneficial for overall health and wellbeing. However, very high-intensity activity in hot conditions should be approached with caution. Allow adequate cool-down time and ensure access to fresh water and shade.

Illness and infection

Systemic illness — particularly conditions causing fever — may temporarily lower seizure threshold and contribute to breakthrough seizures in some pets whose epilepsy is otherwise well-controlled. If your epileptic pet becomes ill, monitor seizure frequency carefully and contact your vet if seizures increase. This is particularly important if your pet is on phenobarbital, as illness can affect how the drug is metabolized.

Hormonal factors

In intact female pets, hormonal cycles can influence seizure frequency. Some dogs experience seizure clustering around the period of estrus (heat). Spaying is often discussed as a potential management consideration in intact females with epilepsy whose seizures show a cyclical pattern. Discuss this with your veterinarian if you notice a hormonal pattern to your pet's seizures.

Light and flicker sensitivity

Photosensitive epilepsy — seizures triggered by flickering lights — is well documented in humans but less common in dogs. A small number of dogs with idiopathic epilepsy appear sensitive to specific visual stimuli. If you notice your pet's seizures consistently occurring around television screens, video games, or flickering lights, document this and discuss it with your vet. This is not a common trigger but is worth noting if the pattern is consistent.

Keeping a trigger diary

Because triggers are individual — what provokes seizures in one pet may have no effect in another — keeping a detailed seizure diary (see Guide 07) is the most practical way to identify your pet's specific patterns. Record not just the seizure itself but what happened in the 24–48 hours before: stress events, sleep quality, exercise level, diet changes, illness, and environmental factors. Over time, patterns often emerge that are specific to your individual pet.