The UK and much of Europe is currently experiencing a heat wave (mid July 2022).

We are, by and large, not used to this although I fear that we may need to adapt, due to climate instability.

For those of us who enjoy activity, being active in the heat is a challenge and can be a medical risk for many.

Because not only do we have to take into consideration the temperature on a thermometer, but we also need to account for the humidity, since this has an impact on the body’s ability to lose heat. It is possible to run marathons in the desert more safely than a humid summers day.

Hydration status, electrolyte balance and other physiological conditions also have a role.

So how do we develop flight rules for exercise in the heat?

Firstly, know your body, and pay attention to it. Getting off the aircraft from a cool region and plunging straight into a desert marathon is asking for trouble. Allowing time to adapt and preferably having mimicked the conditions previously is a much smarter idea.

Secondly, understand your hydration and physiological status. Medically, you should expect a fluid balance of approximately 30ml per kilo per day. This does include the water in vegetables and fruit so is not just liquid water. You will also need to maintain a good electrolyte balance for yourself. If you are a ‘salty sweater’ (your t shirt develops white stains as the sweat evaporates or your lips taste salty) then you will need to replace more of both sodium and potassium in the correct proportions. Most sports electrolyte supplements cover this and advertising aside (we are not sponsored) Succeed caps, SIS electrolyte tabs and High Five electrolyte tabs have always done well during my endurance training career. Others are available and you don’t need the sugary sweetness of most sports drinks for anything under an hour anyway.

The other, under reported element to track during activity is heart rate. In general, if your heart rate is higher than you would expect for a specific workload, then you are possibly dehydrated and certainly accumulating heat stress, with your body finding it hard to stay cool enough. If it is dropping and you are struggling to elevate it to the target ranges then you may be suffering with cardiac fatigue. In either case, back off, drink, reflect and wait for it to settle before making the decision to go or no go. A personal rule is to take off 10 beats from my target heart in non acclimatised heat as a safety margin.

Summary:

• Heat is a stressor
• Acclimatise and adapt if possible
• Hydrate using electrolytes if indicated
• Monitor heart rate if possible and set yourself safety limits

Onwards and stay cool.

And of course, if you need more detailed input on optimising your training, resolving injuries and improving your health span, contact us.

Note: this article is a generic guide and not specific advice. If you have any health concerns or underlying conditions, seek support from your registered medical professional and care providers.