The UK is currently experiencing unprecedented weather conditions. The Met Office has issued a rare Red Extreme Heat Warning, with temperatures soaring past 36°C. Driven by an intense sub-tropical heat dome, this isn’t just standard summer weather; with high humidity levels also, it feels soooooooo much hotter.
When conditions are this bad, your training wardrobe is your first line of defence. Staying cool and protecting yourself from the suns UA and UVB rays requires a complete shift in the types of technical wear we are used to on a day to day.
Why Controlling Core Body Temperature Matters
Your body acts like a finely tuned thermostat, constantly working to keep its internal core temperature around 37°C. To shed excess heat, the brain signals blood vessels to dilate and prompts sweat glands to start pumping. The evaporation of this sweat against your skin is what actually cools your down.
However, with exceptionally high humidity, this process is not as efficient. When the air is saturated with moisture, sweat cannot evaporate efficiently and if your choice of clothing traps that moisture against your skin, your core temperature will quickly begin to climb. This spike increases your risk of severe heat stress, heat exhaustion and potentially fatal heatstroke.
The Hidden Performance Tax
Athletes at all levels will feel the physical toll of this extreme weather. When you overheat, your body triggers a massive survival pivot. It redirects oxygen-rich blood away from your muscles and major internal organs, sending it straight to the skin’s surface to assist with cooling.
This drastic shift results in a severe, immediate drop in physical performance:
- Elevated Heart Rate: Your heart must pump significantly faster to maintain blood pressure.
- Rapid Muscle Fatigue: Muscles are starved of optimal oxygen delivery, making even slower paced runs feel exhausting.
- Brain Fog: Dehydration and heat stress impair cognitive function, slowing down your coordination and decision-making abilities.
Smart Technical Fabric Choices for Running in the Heat
To help your body’s natural cooling mechanisms, you should follow three golden rules when selecting your run outfit:
- Embrace Advanced Synthetics: Ditch everyday lifestyle fabrics like cotton, which trap moisture and become heavy. Choose advanced technical blends like polypropylene, polyester microfiber, or nylon. These engineered fabrics pull sweat off your skin and spread it across the surface for rapid evaporation.
- Prioritise Ventilated Cuts: Tight, restrictive ‘gym wear’ hugs the skin and traps body heat. Opt for running gear with ventilation holes, open mesh zoning, and looser cuts. This allows air to flow freely over your hot skin, creating a cooling microclimate.
- Stick to Light Colours: Dark technical tops act as heat magnets by absorbing the sun’s radiation. Keep things comfortable by wearing white, neon, or pastel running gear that actively reflects solar energy away from your body.
Total UV Protection for Hot Weather Running
If you are determined to head out for a run during this heatwave, adjusting your gear is non-negotiable. Running in the sun unprepared is not hardcore, it’s just plain stupid. While it is tempting to wear as little as possible, exposing bare skin to direct sunlight actually accelerates heat absorption and risks severe UV damage. Instead, look for technical gear engineered with a UPF (Ultraviolet Protection Factor) rating of 50+, which blocks out 98% of harmful UVA and UVB rays.
Here is how to kit out your entire body for maximum protection and optimal cooling:
- Head: A lightweight, breathable running cap or visor is essential. Look for versions with mesh ventilation and dark under-brims to reduce sun glare. Bald head? Cover it up! Simple.
- Eyes: Protect your vision with UV400-rated running sunglasses that feature anti-slip nose pads to stay secure when you sweat.
- Upper Body: Wear a loose, long-sleeved UPF running top made of technical moisture-wicking fabric that physically shields arms from direct solar radiation. Garment options engineered specifically for hot weather performance include:
- Janji Sunchaser 50: Constructed from cool-to-the-touch, cling-free fabric offering premium UPF 50 protection that won’t wear off.
- Arc’teryx Sima Pullover Hoody: An ultralight, highly breathable choice featuring quick-drying Diem polyester and a low-profile protective hood.
- Raidlight R-Light Long Sleeve: Features strategic laser-cut ventilation micro-perforations across the back and chest to maximise airflow during intense runs.
- Lower Body: Opt for breathable, split running shorts to maximize airflow. If you suffer from inner-thigh chafing exacerbated by sweat, wear lightweight running tights or cycling shorts featuring flatlock seams and built-in UV protection.
- Feet: Ditch cotton socks entirely, as they hold onto water and guarantee painful blisters. Switch to thin, synthetic technical running socks designed to wick moisture away from your skin.
By dressing intentionally, choosing protective fabrics, and avoiding outdoor workouts during peak sunshine hours (11am to 3pm), you can safely navigate this historic British summer. Stay covered, stay hydrated, and stay cool. Oh and don’t forget the suncream!
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