Summer training: staying cool when it counts

Heat is one of the toughest training conditions there is. It raises heart rate, speeds fatigue and makes even familiar sessions feel hard. A few smart choices about timing, hydration and clothing can make summer sessions safer and more productive, and this guide sets out the ones we find most useful.

These are general suggestions, not medical advice. If you have a health condition, or are unsure how your body handles heat, speak to a doctor or qualified coach before training in hot conditions.

Choose the right layer

Light, open fabrics move air across the skin and let sweat evaporate, which is how the body cools itself. Lighter colours reflect more heat than dark ones, and a loose, flowing fit lets air circulate. Avoid heavy fabrics and anything that clings when wet.

Look for ventilated panels, mesh zones and fabrics that move moisture away from the skin. A vest or a short-sleeved top is usually cooler than a long-sleeved one, but in very strong sun, a light long-sleeved layer can protect the skin and may feel cooler than bare arms.

Train at the cooler end of the day

Early mornings and evenings are easier on the body. If you have to train at midday, shorten the session, lower the intensity and choose a shaded route. Be especially careful with hard efforts in the heat, because the body takes time to adapt.

Acclimatise gradually

The body adapts to heat over one to two weeks. Start with shorter, easier sessions and build up gradually. If you are travelling to a hotter place, allow time to adjust before racing or hard training.

Drink early, not late

Hydrate before you feel thirsty, and replace fluids steadily through longer sessions. For efforts longer than an hour, consider a drink that includes electrolytes. Pay attention to your body, and be aware of signs such as dizziness, headache, nausea or confusion. These are reasons to stop, cool down and get help if necessary.

Protect your skin

Sun protection matters as much as heat management. Use sunscreen on exposed skin, wear a cap or visor and sunglasses, and choose clothing with good coverage. Reapply sunscreen on long sessions.

Use water smartly

Pouring water over the head and neck, or wearing a wet cap or neck band, can reduce the feeling of heat. Cold water on the wrists and the back of the neck cools quickly. Where it is safe, a swim or a cool shower after training helps recovery.

Adjust your pace

Heat changes what effort feels like. A pace that is easy in cool weather can feel hard in heat. Use effort, not pace, as your guide, and give yourself permission to slow down. A slower session in the heat can have the same training effect as a faster one in the cool.

Recover well

After a hot session, cool down gradually, rehydrate and eat something. Change out of damp clothing promptly, and wash it soon, because sweat and heat make garments hold odour. Sleep and rest matter more in hot spells because the body works harder.

Kit for hot days

Our Velocity collection is built for exactly these conditions. It uses open knits, laser-cut ventilation and ultra-light wovens to keep air moving and weight low. Visit the collections page to see the full range, and the retailer page to find a partner near you.

Share your tips

If you have tips for staying cool, we would love to hear them. Use the contact page to tell us what works for you, and we will share the best ideas.

Understanding how the body handles heat

When you exercise, your muscles produce heat, and your body cools itself mainly by sweating. In dry air, sweat evaporates quickly and cools the skin. In humid air, it evaporates slowly, so you sweat more and cool less, and exercise feels much harder. That is why a humid 28 degrees can feel tougher than a dry 35. Knowing the difference helps you choose when to train, what to wear and how hard to push.

Your body also loses salt as well as water when it sweats. For short sessions this rarely matters, but on long, hot days, replacing salt as well as fluid keeps you feeling better for longer.

Planning a summer week

A sensible summer week mixes easy and hard days and puts the hardest efforts at the coolest times. Keep one or two days lighter, and treat sleep and food as part of training. If a forecast looks extreme, move sessions indoors or take a rest day. Missing one workout will not change your fitness, but heat illness can end a season.

Sample session ideas for hot days

Adapt your training to the weather. A steady, easy session of thirty to forty minutes in the cool of the morning is a good summer staple. Intervals can be shorter, with longer recoveries. Cross-training in a pool or a cool gym is a good alternative on the hottest days. Strength sessions can be done indoors, with a fan, in light clothing.

Listen to how you feel. Heat affects everyone differently, and the right plan for a seasoned athlete is not the right plan for a beginner.

Looking out for others

If you train in a group, watch for signs of heat illness in your companions. These include heavy sweating followed by a sudden stop, flushed or very pale skin, confusion, nausea and fainting. Stop, move to shade, cool the person with water and call for help if they do not recover quickly.

Cooling down afterwards

Walk for a few minutes to let your heart rate come down, then drink and eat. A cool shower and a change into dry clothes help the body recover. If you feel unwell afterwards, rest and seek medical advice if symptoms continue.

Stay safe, stay hydrated and enjoy the season.

About JISDO

JISDO Sportswear designs performance apparel for athletes and everyday movers. Media enquiries: hello@jisdo.com.