Hot stuff!

It finally feels like we're saying goodbye to the winter. The evenings are getting lighter and the spring sunshine is getting warmer. Whilst this warmer weather makes training a lot more bearable, it does present some challenges for long distance endurance athletes. Even this early on in the year, it's easy to underestimate how quickly we get warm when exercising. It’s important to remember that keeping cool is better than looking hot! 

Our bodies are pretty sophisticated and maintain a constant internal temperature in face of ever-changing environmental challenges. However, these challenges are somewhat exaggerated during periods of high intensity or prolonged exercise. Our ability to cope with these challenges will influence our performance during an event like the marathon or a triathlon.

When we exercise, we are actually pretty inefficient and so ~80% of the energy released is given off as heat with only ~20% used to fuel your muscles. To maintain a constant core temperature, the excess heat generated by the muscles is transported to the skin by increased blood flow. If exercise continues and core temperature increases, the body will begin sweating in order to remove excess heat by evaporation. Sweating has a limited affect unless it can evaporate or be wicked away from the skin.

If it’s chilly on race day or at the beginning of your long training session, avoid the temptation to wear too many additional clothes. These will act as insulation and interfere with heat transfer to the skin and sweat evaporation. This in turn will increase heat storage, which may result in fatigue and reduced performance. Instead, try using a bin liner or something that can be thrown away to keep you warm at the start. Don’t worry, you’ll soon warm up when you start exercising even in cool and overcast conditions!

Also, it’s important to be aware that your body tends to utilise muscle glycogen at a higher rate when exercising in the heat. Lactate accumulation also tends to be higher in warmer weather and when combined with reduced muscle glycogen could result in fatigue meaning you “hit the wall” earlier than anticipated. Temperatures can rise quite quickly during the day even if it may be chilly first thing in the morning. If temperatures are likely to be relatively warm on the day of your event, it may be a good idea to reduce your initial pace in order to help conserve your fuel stores for later on.

Finally, when sweating becomes the main way of removing excess heat, sweat loss must be matched by fluid consumption in order to avoid dehydration. A certain level of dehydration is inevitable because our stimulus to drink may not occur until we have already incurred a small water deficit. Dehydration will reduce skin blood flow and sweating responses during an event like a marathon or triathlon which will increase core temperature and potentially bring about the onset of early fatigue. Make use of the water stations and feeding stations along the route and aim to drink to thirst. The sports drinks will not only provide you with a source of fuel but they also contain electrolytes which help replace some of the lost salts and minerals. You should also refer to the medical advice issued the event organisers and take time to look at the course map to ensure you are familiar with where the water/feeding stations are positioned.

So, in order to optimise your Spring training or race performance, aim to be cool rather than look hot! If it is cold outside, wear layers that can be easily removed & replaced to help maintain skin airflow/regulate deep body temperature, look to reduce your race pace and keep hydrated.