Nutrition and heatwaves: how to adjust your intake when temperatures exceed 30°C?

Training when it's over 30°C presents an additional challenge for the body. To maintain a stable body temperature, the body sweats more, water loss increases, and recovery can become more difficult.

In these conditions, nutrition no longer serves only to meet energy needs: it becomes a real tool to limit dehydration, preserve performance, and promote recovery.

Should you only drink water? Are electrolytes essential? What foods should you prioritize before a session? Here are the main adaptations to implement during periods of high heat.

Why does heat impact performance?

When the outside temperature rises, the body must dedicate part of its energy to dissipating the heat produced by exertion.

Sweating increases, heart rate rises more quickly, and the sensation of effort often appears earlier than at moderate temperatures.

Result:

• performance decreases more quickly;
• fatigue appears earlier;
• recovery may be slowed;
• the risk of dehydration increases.

This is why the nutritional strategy becomes particularly important when the mercury exceeds 30°C.

Hydration: your number one priority

Dehydration is probably the primary factor likely to impair performance during periods of high heat.

It is recommended to:

• start your session already well hydrated;
• drink regularly even before feeling thirsty;
• adjust quantities according to the duration of effort and sweating;
• continue to drink after the session to compensate for losses.

A fluid loss corresponding to only 2% of body weight can already lead to a decrease in physical and cognitive performance.

When do electrolytes become useful?

Sweat does not contain only water. It also leads to losses of sodium, potassium, chloride, and, to a lesser extent, magnesium.

A simple, short, low-intensity session generally does not require a specific drink.

However, electrolytes can be beneficial in several situations:

• workouts lasting more than an hour;
• very intense sessions;
• competitions;
• people who sweat profusely;
• days with multiple training sessions.

What to eat before a hot weather workout?

The goal is to provide enough energy without overloading digestion.

A few hours before exercise, prioritize:

• easily digestible carbohydrates (rice, potatoes, oatmeal, bread, fruits);
• a source of lean protein;
• good hydration.

Conversely, it's better to limit just before the session:

• very fatty meals;
• very spicy foods;
• excessive alcohol;
• very heavy meals.

These foods can slow down digestion and increase the feeling of discomfort when it's very hot.

How to eat after the session?

Recovery is based on three priorities:

1. Rehydrate the body.
2. Compensate for electrolyte losses if they were significant.
3. Provide protein and carbohydrates to promote muscle recovery and replenish energy reserves.

A complete meal or a protein shake accompanied by a carbohydrate source is often a simple solution after a summer workout.

Foods to prioritize during a heatwave

During periods of high heat, certain foods combine hydration, freshness, and nutritional intake.

• watermelon;
• melon;
• cucumber;
• tomatoes;
• zucchini;
• strawberries;
• peaches;
• yogurts;
• cottage cheese;
• homemade smoothies rich in fruits and protein.

These foods provide water but also vitamins, minerals, and carbohydrates useful for supporting physical activity.

The most common nutritional mistakes

As temperatures rise, certain mistakes are regularly made:

• waiting to feel thirsty to drink;
• completely cutting out carbohydrates;
• forgetting protein because appetite decreases;
• consuming a lot of alcohol, which promotes dehydration;
• neglecting recovery after workouts.

In the long term, these habits can increase fatigue and limit training adaptations.

Example of a daily diet when it's very hot

Here is an example of an eating plan for an athlete training at the end of the day:

• Breakfast: skyr or cottage cheese, oatmeal, fresh fruit.
• Lunch: rice, chicken, seasonal vegetables.
• Snack: banana and yogurt or protein shake.
• During training: water or an electrolyte drink depending on the duration of effort.
• Dinner: fish, potatoes, mixed salad, fruit.

This is not a universal model but an example showing that it is possible to maintain a balanced diet even when the heat reduces appetite.

Useful food supplements in summer

Food supplements do not replace a balanced diet, but some may have a place depending on needs:

• electrolytes to compensate for losses due to sweating;
• protein powder when it is difficult to meet daily intake;
• carbohydrate drinks during prolonged efforts or summer competitions.

The choice depends primarily on your sports practice, the duration of sessions, and your level of sweating.

What to remember

When temperatures exceed 30°C, it's not enough to drink more. Adapting your nutrition involves anticipating fluid losses, maintaining sufficient carbohydrate and protein intake, choosing easily digestible foods, and optimizing recovery.

By adopting these few good practices, it is entirely possible to continue training effectively throughout the summer, even during periods of high heat.