Sleep is often one of the first things to suffer when life gets stressful – yet it’s one of the most important foundations for mental wellbeing. For those living with emotion dysregulation, disrupted or insufficient sleep can make it even harder to cope with daily challenges. With the UK experiencing increasingly frequent heatwaves, sleep becomes even more elusive, and the impact on our mental health can be significant.

The vital role of sleep in emotional regulation

Sleep isn’t just about physical rest – it’s deeply connected to how we think, feel, and respond to the world around us. A consistent, good-quality sleep routine plays a key role in emotional regulation. When we’re well-rested, we’re more likely to think clearly, solve problems effectively, and respond to difficult situations with greater resilience.

In contrast, poor sleep – whether due to insomnia, disrupted patterns, or environmental factors – can intensify emotional reactivity. Irritability, mood swings, anxiety, and difficulty concentrating are all common consequences of sleep deprivation. For individuals with Borderline Personality Disorder (BPD) or others engaging in Dialectical Behaviour Therapy (DBT), regular sleep can make the difference between using skills effectively and feeling emotionally overwhelmed.

How heatwaves disrupt sleep

Heatwaves aren’t just uncomfortable – they pose a real challenge to getting proper rest. In the UK, many homes aren’t built to stay cool in extreme temperatures. Night-time temperatures over 20°C make it harder for our bodies to cool down enough to initiate and maintain sleep. This leads to more tossing and turning, fragmented sleep, and waking up feeling anything but refreshed.

When our sleep is compromised by environmental factors like heat, our capacity to manage emotions can quickly unravel. We may find ourselves snapping at loved ones, struggling to focus at work, or feeling more hopeless and tearful than usual. The effects can be cumulative – one or two bad nights of sleep might feel manageable, but after several days or weeks, the emotional toll adds up.

DBT, sleep, and the PLEASE skills

In DBT, one of the key modules focuses on Emotion Regulation. Within this, there’s an acronym many clients will recognise: PLEASE. It stands for:

• PL: Treat Physical Illness
• E: Eat balanced meals
• A: Avoid mood-altering substances
• S: Sleep enough
• E: Exercise regularly

The “Sleep enough” part isn’t just about quantity, but also quality and consistency. Prioritising sleep is an essential self-care step that can make all the other DBT skills more accessible. When we’re exhausted, it’s harder to be mindful, observe our urges, or apply opposite action. Keeping sleep on track gives us the best chance of managing our emotions skilfully.

Tips for managing sleep during a heatwave

While we can’t control the weather, there are some practical strategies that might help improve sleep quality during hot spells:

• Cool the room down during the day: Keep curtains closed to block out sunlight, and use a fan to circulate air. A bowl of ice in front of a fan can offer a DIY cooling effect.
• Cold water tricks: Try a cool shower before bed, or place a damp washcloth in the fridge to use on your neck or wrists.
• Adjust your sleepwear and bedding: Lightweight, breathable fabrics like cotton can make a big difference.
• Hydration and caffeine: Drink plenty of water throughout the day, but avoid too much fluid late at night. Steer clear of caffeine after mid-afternoon.
• Stick to a wind-down routine: Even if you’re uncomfortable, try to follow a consistent pre-bed routine to signal to your brain that it’s time for rest.
• Use DBT skills to soothe distress: If you find yourself lying awake, try using TIPP (Temperature, Intense exercise, Paced breathing, Paired muscle relaxation) or half-smiling and willing hands to bring your nervous system back into balance.

Final thoughts

Sleep and mental health are intricately linked, and during a heatwave, that connection becomes even more apparent. Prioritising rest and using DBT skills to support emotional regulation can help reduce the toll of hot, sleepless nights. At DBT-UK, we understand how difficult it can be to stay regulated when your body is tired and overheated – but even small steps to care for your physical needs can lead to meaningful emotional improvements.

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