Summer: how to regulate body temperature

Cristina Lanfranchi

Body temperature rises during summer when feelings of fatigue and/or exhaustion, and occasional cramps may set in.

To safeguard against these discomforts, we need to know how to adapt the body to high temperatures. How do we do this? To answer this question accurately, it’s necessary to understand what actually happens to our bodies when exposed to high temperatures.

Humans are homeothermic, meaning they maintain a constant internal body temperature in the range of 36.1°C to 37.8°C, and only tolerate relatively small changes in temperature. Exposure to high temperatures leads the body to self-regulate through four heat-dissipating response mechanisms: conduction; convection; radiation; and evaporation (the main one in hot situations).

The heat response mechanisms

The human body is a perfect machine. Sudden variations in weather (now exacerbated by climate change) and/or rising temperatures set off alarm bells in our bodies that activate response mechanisms involving the hypothalamus, the thermoregulation centre that functions as a veritable thermostat.

Heat stress shifts blood flow to the periphery resulting in increased sweating and elimination of excess body heat. But that’s not all. The situation can be complicated if we are present to high humidity in addition to high temperatures. In these conditions, the effectiveness of heat loss through sweat decreases dramatically. Adjusting to heat, therefore, can take from a few days to a few weeks.

Tips for fighting back

To understand how to regulate your body temperature and combat the heat, here are some practical tips that are also useful for those who don’t want to give up exercising.

Summer is the perfect time to get back in shape because the pace slows down and it's easier to take care of yourself. The following steps will help you handle the heat:

1. Avoid unnecessary stress on the body by making sure it gets used to the sun properly and gradually. Two hours a day of exposure for the first few days is enough. With this in mind, we can take care of our skin and prepare it for the sun's rays. How? First by using appropriate sunscreens. Nutrition can also play an important role, for example, by taking advantage of the beneficial effects of carotenes and carotenoids. Recent studies have shown that these substances can contribute to managing UV radiation and moderating photo-oxidative stress correlated with skin aging. Among the most prominent nutrients are lycopene, phytoene, phytofluene, lutein, and zeaxanthin, which are found mainly in leafy green vegetables, carrots, apricots, and tomatoes. In addition, to moderate skin cellular stress, it’s important to eat a diet rich in polyphenols. Fruits are particularly rich in them, for example, the anthocyanins found in blueberry skins or the oligomeric proanthocyanidins (OPCs) found in grape seeds, which play a supporting role in collagen formation, or epigallocatechin gallate from green tea (EGCG), all of which are strong antioxidants that can reduce the collagen-degrading activity of metalloproteinases. In this regard, there are specific products on the market that have formulas enriched with many of the aforementioned polyphenols.

2. Carve out time for physical activity. The 1996 Surgeon General Report stipulated that "physical inactivity results in a worsening of general health status." So, even in hot weather, let's not sit still. What to do? Aerobic-lipid exercise (i.e., all those activities performed at low to medium intensity in which lipid oxidation is promoted) can improve metabolic functions. Next advance to walking, running and swimming during the cooler hours of the day (early morning or sunset), starting with a minimum of 25 minutes and gradually increasing the duration.

3. Maintain a good level of hydration is definitely the most important advice. Drinking at least 2 litres of water per day, preferably not too cold and in small sips over 24 hours (the ideal timing is every 15 minutes), promotes decreasing the heart rate and retaining more minerals within the body. For example, going from a climate of 27°C to 37°C leads to losing five times more body fluids in one hour. But sweat isn’t composed of water alone. Large amounts of mineral salts (sodium, potassium, magnesium and calcium are the main ones) are lost through sweat. Increasing fruit and vegetable consumption certainly has a positive impact, but supplementation with mineral salts is strongly recommended in these cases.

4. Adopt an anti-inflammatory eating strategy that balances macronutrients and allows you to arrive at the next meal with an adequate level of hunger, without experiencing drops in energy and mental clarity. Like the Zone Diet, for example, which advocates for small, frequent but always balanced meals composed of easily digestible and minimally processed foods, combining carbohydrates with a low glycaemic load (especially colourful seasonal fruits and vegetables, rich in antioxidants), with proteins (for example, fish, eggs, and white meat ) and good fats (EVO oil). Polyphenols are of paramount importance. Anthocyanins (such as delphinidins), which are abundant in all red fruits and maqui, have a strong antioxidant action because they stimulate the enzyme AMPK (the so-called "enzyme of life"). And then there are flavanols (catechins and epicatechins) – abundant in cocoa beans, which maintain the elasticity of blood vessels thus improving blood flow. What’s the result? We feel less tired and more lucid. Finally, spices and herbs such as sage, rosemary, mint, oregano, cinnamon, turmeric, and paprika, which not only help give flavour to our dishes by reducing the use of salt, but are also a source of polyphenols, again with antioxidant action.

By following these tips, we hold all the cards to experience the summer months at their best – even when weather conditions are not always "pleasant." Our body is a wonderful machine capable of defending and self-regulating itself, but with some good habits we can do a lot to help and support it.

 

BIBLIOGRAFIA

2005. H. Wilmore, D. L. Costill “Fisiologia dell’esercizio fisico e dello sport”, Calzietti Mariucci editori 2005.
2006. D. McArdle, F. I. Katch, V. L. Katch “Fisiologia dell’esercizio - l’essenziale”, Piccin 2016.

Dana S.; Green J., Roberts R. – Clinical evidence shows long-term beneficial effects of Florago Lutein on Human Skin – Kemin Foods L.C. 2012

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2. Ricordi “Il codice della longevità sana”, Mondadori 2022