Beat the Heat: Protect Your Energy, Focus and Performance

When temperatures rise, most of us expect to feel a little uncomfortable. What many professionals don't realise is that heat and humidity can quietly undermine cognitive performance, decision-making and productivity long before they become a medical concern.

Your body works hard to maintain a stable core temperature of around 37°C. In hot weather, blood flow is redirected towards the skin to dissipate heat, while sweat evaporates to cool the body. However, humidity makes this process far less effective. When the air is already saturated with moisture, sweat cannot evaporate efficiently, leaving you hotter despite sweating more (Cheung et al., 2016).

The result isn't just physical discomfort. Even mild dehydration of around 2% of body weight has been shown to impair attention, working memory, mood and executive function, all essential for leaders, knowledge workers and anyone making important decisions throughout the day (Ganio et al., 2011).

The good news is that staying cool isn't about expensive gadgets or ice baths. Small, evidence-based habits can make a meaningful difference.

Start with hydration, but don't wait until you're thirsty. Thirst is a relatively late signal that fluid balance is already beginning to decline. Drinking regularly throughout the day is more effective than consuming large amounts all at once. If you're exercising heavily or spending prolonged periods outdoors, replacing electrolytes alongside fluids can also help maintain performance.

Think carefully about your environment. Closing blinds during the hottest part of the day, using fans to improve air movement and planning demanding mental work during cooler morning hours can reduce thermal strain. If you're commuting or walking between meetings, seek shaded routes where possible and wear lightweight, breathable clothing that allows sweat to evaporate.

Nutrition also plays a role. Large, high-fat meals increase metabolic heat production, making you feel warmer. Lighter meals containing fruit, vegetables and foods with high water content can support both hydration and comfort during hot weather.

Finally, respect recovery. Sleep often deteriorates during hot, humid nights because the body struggles to lower its core temperature before sleep onset. Keeping the bedroom cool, using breathable bedding and taking a lukewarm shower before bed can help support better overnight recovery (Harding et al., 2020).

Heat isn't simply a comfort issue, it is a performance variable. By staying ahead of dehydration, adapting your environment and adjusting your daily routine, you can protect your concentration, maintain energy levels and continue performing well, even when the temperature climbs.

References:

Cheung, S. S., Lee, J. K. W., & Oksa, J. (2016). Thermal stress, human performance, and physical employment standards. Applied Physiology, Nutrition, and Metabolism, 41(6), S148–S164.

Ganio, M. S., Armstrong, L. E., Casa, D. J., McDermott, B. P., Lee, E. C., Yamamoto, L. M., ... Lieberman, H. R. (2011). Mild dehydration impairs cognitive performance and mood of men. British Journal of Nutrition, 106(10), 1535–1543.

Harding, E. C., Franks, N. P., & Wisden, W. (2020). The temperature dependence of sleep. Frontiers in Neuroscience, 14, 336.

World Health Organization. (2024). Heat and health. https://www.who.int/news-room/fact-sheets/detail/climate-change-heat-and-health