Author: Geir Gunnar Markusson, Nutritionist MSc., Unbroken

Summer is one of the best times of year to train. The days are longer, the trails are dry, and spending time outdoors simply feels good. Whether you're running, cycling, hiking, or preparing for your next race, warmer weather usually means more opportunities to move.

But warm weather changes more than your training environment. It changes how your body responds to exercise.

You work harder to stay cool, use more energy, and often need more recovery between sessions. The good news is that your body adapts remarkably well when you give it the right support.

Here's what every athlete should know about training and recovering during the summer months.

Why the same run feels harder in the heat

If you've ever wondered why a comfortable pace suddenly feels challenging on a hot day, you're not imagining it.

When you exercise in warm conditions, your body directs more blood to the skin to help regulate temperature. At the same time, your muscles still need oxygen and energy to keep moving efficiently.

This means your heart has to work harder, even when you're maintaining the same pace you comfortably held a few months earlier. That's why heart rate often climbs faster in the heat and why familiar workouts can suddenly feel more demanding.

If pace, power, or endurance seem to drop on hotter days, it doesn't necessarily mean you're losing fitness. More often, it's simply your body adapting to the conditions.

Heat uses more of your energy stores

Training in warm conditions doesn't just feel harder. It also changes how your body uses fuel.

Research shows that the body relies more heavily on stored carbohydrates during exercise in the heat. As a result, you may finish a workout feeling more depleted than you would after the same session in cooler weather.

Many athletes notice this as heavier legs, unusual fatigue, or a feeling that recovery takes longer than expected.

Fortunately, the body adapts. Gradual exposure to warmer conditions improves heat tolerance and helps your body become more efficient over time. This is why building up to summer training is far more effective than trying to push through extreme heat all at once.

Recovery matters more in summer

Every training session creates stress that your body must repair afterward. That's how fitness improves.

During the summer, recovery becomes even more important because your body is dealing with more than just the workout itself. You're losing more fluids, using more energy, and often sleeping less well during warm nights.

Research suggests that exercise in hot conditions may increase the body's use of amino acids, the building blocks needed for muscle repair and recovery. At the same time, higher nighttime temperatures can reduce sleep quality, limiting the time your body has to fully recover.

That's why summer is often when recovery makes the biggest difference. The athletes who continue progressing aren't necessarily training more. They're recovering better.

Staying on top of your fluid intake, prioritising sleep, and providing your body with the essential amino acids needed for muscle repair can help you maintain consistency throughout the season.

Small things add up

Most athletes don't notice the effects of summer training after one workout. They notice them after a few weeks. A slightly higher heart rate. A little more fatigue. Recovery taking longer than usual. Sleep that isn't quite as restorative. Individually, these aren't major problems. Together, they can leave you feeling flat and wondering why training suddenly feels harder. Often, it isn't a fitness problem. It's a recovery problem.

How to stay ahead this summer

The goal isn't to avoid summer training. The goal is to recover well enough to benefit from it. A few simple strategies can make a significant difference:

• Build heat exposure gradually to allow your body to adapt.
• Train earlier in the morning or later in the evening when temperatures are lower.
• Keep your fluid intake steady before, during, and after exercise.
• Refuel properly after training, including adequate protein and essential amino acids.
• Keep your sleeping environment as cool as possible.
• Allow a little more recovery time during prolonged periods of heat.

A practical tip for summer training

Recovery starts before your workout ends. Adding Unbroken to your routine is a simple way to provide your body with essential amino acids before and after exercise, helping to nourish your muscles and support recovery on the go.

Before heading out, prepare two glasses of cold water with one Unbroken tablet dissolved in each. Drink the first around 30 minutes before training and the second immediately afterwards.

It's a simple habit that helps support recovery and readiness for your next training session.

Make summer your strongest training block

Summer doesn't have to mean slower progress. When you understand how your body responds to warmer conditions and adjust your recovery accordingly, the summer months can become one of the most productive periods of your training year.

Enjoy the longer days. Take advantage of the extra opportunities to get outside. Prioritise recovery, stay consistent, and make the most of your training.

Ready for the next run.